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An Engineer in Wonderland Archives

February 9, 2012

An Engineer in Wonderland - Help Alice with assembler code

I am trying to write some code for a microcontroller - a PIC - and have stumbled across a problem, and a sort-of answer.

As I have no formal training in well-structured assembler code, I suspect my answer is sub-optimal - or even sub-passable - and could do with some help.

My hope is that some kind soul will say 'What you need is to use Shubunkin's inferior parameter pass, or the Smyth-Hamilton's data swap', or some such.

Anyway, this is the problem:

Continue reading "An Engineer in Wonderland - Help Alice with assembler code" »

February 8, 2012

An Engineer in Wonderland - Cunning battery adapter

cleverAdapter.jpgThose clever guy's at Zebralight in China have come up with a neat way of making an LED torch compatible with both CR123 and AA cells.

Electrically, it just means a wider input voltage range - probably 0.9-4.0V.

But mechanically this has previously meant screw-on extension tubes to allow for the longer AA cell - maybe with a narrowed interior to deal with the AA's slimmer profile.

Continue reading "An Engineer in Wonderland - Cunning battery adapter" »

February 1, 2012

An Engineer in Wonderland - 15,000 lm torch

LED torch maker 4sevens has demonstrated the production version of its 15,000 lm XM18 torch - or flashlight as the company would say.

Take a look at this video over at Geeky Gadgets


'Alice'


Should you feel the need, respond to alice@electronicsweekly.com with 'Torch' in the title.

Please don't respond below as our spam blocking system doesn't work and the inbox is overwhelmed by all kinds of generous offers from a multitude of rather annoying people.

No email addresses are collected for marketing (or any other) purposes from responses to this blog. I will keep it that way for as long as possible.

January 27, 2012

An Engineer in Wonderland - How wings really lift

WingsWork.jpgFrom the University of Cambridge: A one minute video sets the record straight on a much misunderstood concept.

The University said: 

It's one of the most tenacious myths in physics and it frustrates aerodynamicists the world over.

Continue reading "An Engineer in Wonderland - How wings really lift" »

January 18, 2012

An Engineer in Wonderland - Op amp needed for a current source

constant current 122.JPGI was pondering a simple way with a low drop-out voltage to power a grounded LED from a grounded supercapacitor. Something that would be tolerant of the LED being powered from elsewhere when the capacitor is empty.

The easiest option is to use a resistor, but this will mean brightness is dependent on capacitor voltage.

A complicated way, which could deliver maximum efficiency and maximum power extraction, is to implement a buck/boost converter.

Continue reading "An Engineer in Wonderland - Op amp needed for a current source" »

January 11, 2012

An Engineer in Wonderland - High Speed 2 maps

Just in case you are curious, the official route maps for HS2 are on the Department for Transport website.

Turn's out that there is a lot of existing rail infrastructure in North London that I have never heard of.

Continue reading "An Engineer in Wonderland - High Speed 2 maps" »

January 3, 2012

An Engineer in Wonderland - DVMs from Santa's workshop

LittleDVMpic.JPGI like to make at least one present for someone at Christmas.

This time it was little pocket DVMs for those gathered around the Christmas tree that maintain their own cars and motorbikes.

A little time consuming, but the result was three happy relatives.

Continue reading "An Engineer in Wonderland - DVMs from Santa's workshop" »

December 13, 2011

An Engineer in Wonderland - Thinner than a human hair

Blah blah blah is 1,000 times thinner than a human hair.

What?

My human hair visualisation is already wobbling at half as thick as a human hair.

Continue reading "An Engineer in Wonderland - Thinner than a human hair" »

November 18, 2011

An Engineer in Wonderland - Thanks Mr Cree, the Mark 6b LED headlight is looking good

Mark6b thumb200.JPGSneezing and sniffing put the brakes on my extensive social life (I claim) and offered a golden opportunity for a few evenings in a chilly workshop.

The result is a Mark 6b LED bicycle headlight and, once more, learning more than I wanted to.

Continue reading "An Engineer in Wonderland - Thanks Mr Cree, the Mark 6b LED headlight is looking good" »

November 17, 2011

An Engineer in Wonderland - Engineering Nobel Prize

It is nice to see that the Royal Academy of Engineering has stepped in to fill a hole in the Nobel Prizes with the Queen Elizabeth Prize for Engineering.

 - Much in the way that the Rolf Schock and Crafoord Prizes fill the maths hole, and the Turing Award does for computing.

So I got to thinking who in the past I would like to give a Queen Elizabeth Prize to.

Continue reading "An Engineer in Wonderland - Engineering Nobel Prize" »

November 16, 2011

An Engineer in Wonderland - An amusing website for those in need of magnification

Never have I come across such an honest sales website.

I am looking for some sort of magnifier because I am going cross-eyed machining the finer bits of the Mark 6b bicycle headlight.

QuickTest.co.uk of Watford offers a wide range of magnifiers, from some seriously wonderful stuff, to some lesser products only there because they sell cheaply.

More of the serious stuff later, but it is the descriptions of the lesser stuff that tickled me.

Continue reading "An Engineer in Wonderland - An amusing website for those in need of magnification" »

November 4, 2011

An Engineer in Fairyland - Millisecond trading?

While I am pondering The Market and things, is millisecond trading really such a good thing?

Even I, who struggled with control theory at university, know that too much gain in system can lead to instability.

And that doing trades faster and faster, unless you proportionally reduce the size of the trades, is increasing the gain of the system.

Continue reading "An Engineer in Fairyland - Millisecond trading?" »

November 2, 2011

An Engineer in Fairyland - Financial engineering?

My fundamental complaint is that real engineering is built on science, and financial engineering is built on bollocks.

I think what confuses people is that in both cases there is a lot of maths between the foundations and the engineering.

Continue reading "An Engineer in Fairyland - Financial engineering?" »

October 6, 2011

An Engineer in Wonderland - Book Review: The Toaster Project

BookReview Toaster Project thumb.JPGRoyal School of Arts post-graduate design student Thomas Thwaites sets himself the task of building a toaster from scratch.

Right from scratch: digging up raw materials in the British Isles and making everything himself.

Continue reading "An Engineer in Wonderland - Book Review: The Toaster Project" »

October 4, 2011

An Engineer in Wonderland - Little PICs for power circuits

I have a soft-spot for low pin-count PICs and have used them for controlling power on several occasions.

So I was intrigued to see Microchip has added a bunch of power-ish peripherals, including a configurable logic block to its 6-20pin PIC10F, 12F and 16F families. 

Continue reading "An Engineer in Wonderland - Little PICs for power circuits" »

September 29, 2011

An Engineer in Wonderland - Alice invents the thyristor

threeTransistors thumb.jpgDoing things with bicycle dynamos is a bit of am obsession with me and several times I have pondered how to supply voltage to things that do not need the whole 3W output.

The trouble with a permanent magnet generator, as these things are, is turning them off as they don't like to stop generating.

Continue reading "An Engineer in Wonderland - Alice invents the thyristor" »

September 20, 2011

An Engineer in Wonderland - Look what Santa* brought me

Blog 200.JPGSome nice people at Cree (*ok, not Santa) spotted my non-too-successful attempt to make a useful +/-4° LED headlight recently and took pity on me.

Apparently the guys in the lab had a hunt around, and the result was that a box of bits dropped onto the Electronics Weekly tech desk, which will soon be making its way to the workshop tucked away behind Alice Towers.

Continue reading "An Engineer in Wonderland - Look what Santa* brought me" »

September 5, 2011

An Engineer in Wonderland - Wooden springs and infinite fretsaws

Roof saw thumb.jpgI was talking to a retired wood worker about a bench-top scroll saw I just bought.

It is the mechanical cousin of the hand-held fret saw, and within it a saw blade under tension moves rapidly up and down cutting what ever you push against it.

The good thing is, by threading the blade through a drilled starter hole, apertures can be cut in sheet material.

Continue reading "An Engineer in Wonderland - Wooden springs and infinite fretsaws" »

September 1, 2011

An Engineer in Wonderland - Hmmm, LED headlamp flop?

Mark6a thumb.JPGIn the name of science and safety, I locked myself away in the workshop over the long weekend to produced a +/-4° LED bicycle headlamp to compare with the +/-5.5° version I made a while ago.

+/-5.5° has seemed a little wide, lighting up road-side shrubs and the road immediately in front of the bike too brightly. 

Mk6a in all its glory. For scale, the lens is 18mm across and the hole is 26mm.

Continue reading "An Engineer in Wonderland - Hmmm, LED headlamp flop?" »

August 29, 2011

An Engineer in Wonderland - Missing the point of LED streetlights

It seems like streetlight buyers are sacrificing efficiency by specifying white LEDs with high colour rendering index (CRI) - scroll way down to 'CRI: an obsession'

Which is odd, because one of the reasons for moving to LEDs is to increase efficiency, and streetlights are pretty efficient already, so you have to work pretty hard to beat them.

Continue reading "An Engineer in Wonderland - Missing the point of LED streetlights" »

August 25, 2011

An Engineer in Wonderland - A well-argued headphone amp design

There is a lot of hype in the world of high-end audio.

And few reasonable people who seem to know what they are talking about, and are prepared to burst bubbles.

One such blogger and forum sage is Northwest Audio & Video Guy

He*, has gone so far as to design his own reasonably-priced headphone amplifier to show what can be achieved without paying a fortune for nonsense.

Continue reading "An Engineer in Wonderland - A well-argued headphone amp design" »

August 23, 2011

An Engineer in Wonderland - PDA woe, and where are the E Ink ones?

Palm III v2.jpgI like to keep data in one place, and for years I used a Palm III

And was mostly happy with it.

It ran for months on two AAA cells, which is my idea of good battery life, rather than two days between charges.

Then, spontaneously, the backlight came on with a buzzing noise and it erased all the data.

Once the battery was flat, it seemed to recover completely.

Continue reading "An Engineer in Wonderland - PDA woe, and where are the E Ink ones?" »

March 30, 2011

An Engineer in Wonderland - Mr Laithwaite's chart arrives

Thanks to the kind contribution of Mr Williams from Swansea, I now have a copy of Professor Eric Laithwaite's informative chart, which puts the physical world in perspective by equating its metrics to electrical parameters.

Actually, Mr Williams sent it to me over a month ago, but I mislaid the email, for which I apologise to him.

Continue reading "An Engineer in Wonderland - Mr Laithwaite's chart arrives" »

March 21, 2011

An Engineer in Wonderland - Messrs Sziklai and Pease save the day

LedCeiling circuit bigThumb.JPGI made up a prototype current regulator for the LED ceiling using a CA3140 and a BUZ11 mosfet, all on a chassis that I once built for a motorcycle voltage regulator.

And it worked, but current was suspiciously high on the upper settings.

Cue the scope and....oh woe.... it was oscillating as the current demand was increased.

Continue reading "An Engineer in Wonderland - Messrs Sziklai and Pease save the day" »

March 9, 2011

An Engineer in Wonderland - Sziklai pair excitement

Sziklai pair mosfet 200.JPGAs a temporary measure, I am knocking together a power supply for my LED ceiling.

The idea is to check-out the choice of brightness levels and the power circuit before I go the whole hog and make a microcontroller version.

I need to control 0-1A through an opamp and some sort of transistor, and the parts bin has yielded a CA3140 and a BUZ11 mosfet.

Continue reading "An Engineer in Wonderland - Sziklai pair excitement" »

March 7, 2011

An Engineer in Wonderland - Contactor conundrums

MotorContactor thumb.JPGAs part of the great lathe re-wire, I have had to learn a bit about contactors.

The starter that came with the lathe had been bolted to the front of the machine, then the front cover had been removed exposing the contactor to the world and allowing it to be operated directly by a finger. And allowing access to ground leakage paths, like fingers.

Continue reading "An Engineer in Wonderland - Contactor conundrums" »

March 4, 2011

An Engineer in Wonderland - Motor treasure

MotorSlipMeasure thumb2.JPGI have been having great fun messing about with motors.

A friend of mine has a new lathe.

Actually, it is an old lathe, a Mark 1 Master from Colchester. 

It weighs half a tonne (or half a ton as it is of such vintage?) and replaces an even more magnificent Colchester Triumph which literally weighs a tonne and was just a little too big for the workshop. 

Continue reading "An Engineer in Wonderland - Motor treasure" »

An Engineer in Wonderland - The spam swamp

Whereas our marvellous IT system seems to be coping well with email spam, the part that deals with comment spam is collapsing.

In an attempt to shore it up, the powers-that-be have changed the settings and now some genuine replies to our blogs are being automatically tagged as spam and discarded.

Continue reading "An Engineer in Wonderland - The spam swamp" »

January 24, 2011

An Engineer in Wonderland - When LED lighting glows at night

Having installed a commercial LED ballast and found that the 'off' setting leaves the LEDs glowing faintly, I have heard of a second case of this phenomenon.

The glorious editor (blessed be the ground he walks upon) stayed in a French hotel room that had LED bedside lights, which also continued to glow when 'off'.

Continue reading "An Engineer in Wonderland - When LED lighting glows at night" »

January 11, 2011

An Engineer in Wonderland - Alice invents a binary joke

Electronics Weekly all-round good egg and webmaster Alun Williams started the world's largest collection of binary jokes elsewhere on this blog, and having scanned the world, we know there are three.

Continue reading "An Engineer in Wonderland - Alice invents a binary joke" »

January 7, 2011

An Engineer in Wonderland - Gorilla Glass

What amazing stuff.

Gorilla Glass is Corning's answer to broken and scratched displays.

It is a flexible glass that is vastly less crackable than more conventional display glasses.

Continue reading "An Engineer in Wonderland - Gorilla Glass" »

January 4, 2011

An Engineer in Wonderland - Alice's LED ceiling is complete (ish)

Ceiling after thumb.JPGI am rather proud of this as there cannot be many fully-LED lit rooms in the world yet.

After a year of contemplation, months of designing, weeks of ordering, days of freezing in the workshop, and hours of wiring in the loft....

Continue reading "An Engineer in Wonderland - Alice's LED ceiling is complete (ish)" »

December 15, 2010

An Engineer in Wonderland - Tenerife mystery machine

Tenerife thumb.JPGIn a niche carved high in the side of a canyon near Masca in Tenerife, I came across this machine.

It is labelled Petter Yeovil.

 

Continue reading "An Engineer in Wonderland - Tenerife mystery machine" »

November 22, 2010

An Engineer in Wonderland - An LED down lighter

LEDceiling thumb.JPGCurious to get our hands on a Helieon LED module to see how the bayonet-fit change-it-like-a-light-bulb system worked, we asked around for a sample. 

Continue reading "An Engineer in Wonderland - An LED down lighter" »

November 17, 2010

An Engineer in Wonderland - Scary aerial

Thing you have a difficult job?

Take a look at this video of two blokes climbing an enormous mast to do some maintenance.


Continue reading "An Engineer in Wonderland - Scary aerial" »

September 27, 2010

An Engineer in Wonderland - Lignum vitae bearings

A programme about a chair from the Caribbean from Radio 4's A History of the World in 100 Objects mentioned the wood lignum vitae, which reminded me of the clocks of John Harrison.

According to the book Longitude, Harrison used the wood in clock bearings for its long-lasting and self-lubricating properties.

Continue reading "An Engineer in Wonderland - Lignum vitae bearings" »

September 24, 2010

An Engineer in Wonderland - ridiculous switching frequencies

I can remember talking to a TDK ferrite guy in Japan once and seeing a look of how-are-we-going-to-make-that-inductor shock on his face when I said there was a dc-dc chip available that operated at 2MHz.

Continue reading "An Engineer in Wonderland - ridiculous switching frequencies" »

September 23, 2010

An engineer in wonderland - Son* of 555?

Reminiscent of the very best analogue apps notes, the data sheet for Linear Tech's rather interesting LTC6992 six pin oscillator/PWM includes a delightful collection of circuits.

I particularly like the Wide Range LED Dimming (0 to 85000 Cd/m2 Brightness - page 29), even though I have still to fathom how control transfers between the two control circuits.

The 6992 is part of a neat little cluster of six pin temporal building blocks, called TimerBlox, that rely on silicon rather than capacitors to set periods.

I feel, at last, there is a worthy successor to Hans Camenzind's venerable 555 within this family.


'Alice'

* Daughter? 


Should you feel the need, respond below.


No email addresses are collected for marketing purposes from responses to this blog. I will keep it that way for as long as possible.

August 24, 2010

An Engineer in Wonderland - Mr Newsom's drill - a marvellous mining machine

Cylindrical drill thumb.jpgThe plight of those unfortunate but lucky souls stuck underground but being rescued in Chile reminded me of a historic shaft boring technique I came across in California.

In the 1930s it was used to drive a vertical 1.5m diameter shaft 300m down into the Idaho-Maryland gold mine in Green Valley California.

There were several innovative features:

Continue reading "An Engineer in Wonderland - Mr Newsom's drill - a marvellous mining machine" »

August 12, 2010

An Engineer in Wonderland - Free relay book

There was a great little free book about electromechanical relays.

It was narrow, tall and blue as I remember.

From NAIS maybe?

Anyway, I have not seen one for a while.

Continue reading "An Engineer in Wonderland - Free relay book" »

August 11, 2010

An Engineer in Wonderland - Build a 20W PC

Want to build a low power x86 PC?

I am sure there are several ways to do it.

But to save yourself some thinking, take a look at Christopher Barnatt of Explaining Computers putting together a 20W PC in this video.

He uses that nice new 510 dual core Atom.

Continue reading "An Engineer in Wonderland - Build a 20W PC" »

August 10, 2010

An Engineer in Wonderland - 20mW stand-by, an expert replies

Several people responded to my 'Full marks for 20mW stand-by' blog about an excellent-looking power-saving device.

One of those was Mark Muegge, v-p of marketing at CamSemi, a company that I casually mentioned in the original.

He wrote:

Continue reading "An Engineer in Wonderland - 20mW stand-by, an expert replies" »

August 3, 2010

An Engineer in Wonderland - Help Mr Reason

Mr Reason commented on this blog with a request.

He wrote:
There was a magazine news item entitled "Engineers Beware", some years ago...

It recounted the story of two college students who created some circuitry for an April fools prank. It was used by an employee of a company, and it led to big problems for that company..

Continue reading "An Engineer in Wonderland - Help Mr Reason" »

An Engineer in Wonderland - More smart meter nanny please?

Smart meter thumb.jpgGood thing 1...
By allowing in-home energy meters to be installed, smart meters could help the population save energy - and should eventually become part of a smart grid which will be able to handle more wind and solar power. *

 

Continue reading "An Engineer in Wonderland - More smart meter nanny please?" »

An Engineer in Wonderland - Blackberrys are officially secure

What an amazing advert for the security of Blackberry phone-plus-personal-organisers.

The governments of Saudi Arabia and the United Arab Emirates are so nervous about not being able to read messages between the handhelds, that they are effectively going to ban Blackberrys.

So, well done Research in Motion, for showing that wireless does not mean insecure.

I suppose there is an outside chance of a bluff? That the two gulf states can read the messages, and are trying to trick people into using them?

'Alice'


Respond below, or to alice@electronicsweekly.
No email addresses are collected for marketing purposes from responses to this blog. I will keep it that way for as long as possible.

July 26, 2010

An Engineer in Wonderland - Full marks for 20mW stand-by

Savasocket.jpgTen out of ten to Leeds-based Energy Saving International for its gadget that cuts the power consumption of mobile phone chargers to 20mW once the phone is charged.

Continue reading "An Engineer in Wonderland - Full marks for 20mW stand-by " »

July 16, 2010

An Engineer in Wonderland - Supercap guy replies

SuperCap circuit thumb.jpgFrom Pierre Mars of CAP-XX

Just responding to your comment in the blog An Engineer in Wonderland - Energy harvesting and supercapacitors.

You are quite right, the final circuit would need 2 x MAX9015, you can't use both op amps in the dual version MAX9107.

Since then I have done some more work... 

Continue reading "An Engineer in Wonderland - Supercap guy replies" »

An Engineer in Wonderland - I don't like tatoos, but.....

Apart from the first one which is a bit pretentions, I was at least entertained by this lot of techno body art.

'Alice'


Respond below if you so wish.

No email addresses are collected for marketing purposes from responses to this blog. I will keep it that way for as long as possible.

 

http://blogs.discovermagazine.com/loom/tag/physics-tattoos/

July 13, 2010

An Engineer in Wonderland - Energy harvesting and supercapacitors

I came across a rather good article on using supercapacitors to buffer energy harvesters.

It was written by Pierre Mars of supercap maker CAP-XX, and published in the Journal of Energy Harvesting.

There is plenty about leakage, and even the problems of charging from 0V  when the chemistry needs a little kick start, it appears.

It ends with an application circuit including a vibration harvester from Perpetuum.

 - Although there is a potential flaw in the circuit, I don't think a MAX9107 could be used for the two comparators as the chip has a common power pin and the circuit requires them to be fed from two different rails.

A most interesting article.

'Alice'


Respond below, or to alice@electronicsweekly.


No email addresses are collected for marketing purposes from responses to this blog. I will keep it that way for as long as possible.

May 27, 2010

An Engineer in Wonderland - Mr Laithwaite's informative chart

The great heavy electrical engineer Eric Laithwaite, at one of his legendary Christmas Lectures, displayed a chart which equated magnetic, electric, thermal and mechanical quantities such as inductance and thermal inertia.

Does anyone remember how it went?

Continue reading "An Engineer in Wonderland - Mr Laithwaite's informative chart" »

May 21, 2010

An Engineer in Wonderland - Artificial life, but not as we'll know it

Dr Craig Venter claims to have made a synthetic bacterial cell.  

However, as far as I can tell - and I am sorry for any errors here - he has:

Read the DNA of an existing bacteria - Mycoplasma mycoides
Synthesised that DNA, adding some sections to aid assembly
Inserted the synthetic DNA into a bacteria whose own DNA had been removed
Persuaded the resulting cell or cells to multiply

Continue reading "An Engineer in Wonderland - Artificial life, but not as we'll know it" »

May 20, 2010

An Engineer in Wonderland - Radio bloody amnesty

radio amnesty.jpg"The UK radio industry today launched a major cross-industry consumer initiative and marketing campaign - the Radio Amnesty - offering consumers a discount on a new digital radio in exchange for their analogue radio, which will be reconditioned and given to needy children in Africa."
 - Industry body Digital Radio UK.

 

                          WHAT????

 It has become a crime to have an analogue radio?

Continue reading "An Engineer in Wonderland - Radio bloody amnesty" »

May 18, 2010

An Engineer in Wonderland - Nature isn't always elegant

Fly trap thumb.JPGLast year, I bought two venus fly traps, one for a friend and one for me.

We fell to discussing how this insect eating plant avoids eating the insects that it relies on for pollination. 

We speculated that the traps would close up during the 'mating' season.

We speculated that the traps' ultraviolet signature would change.

Then they flowered and we discovered we were wrong.  

Continue reading "An Engineer in Wonderland - Nature isn't always elegant" »

April 28, 2010

An Engineer in Wonderland - Thinking microfluidics

Microfluidics thumb.jpgThe University of Michigan has a rather nice video of its lab-on-a-chip in operation.

The remarkable thing about this hydraulic circuit is that it generates is own control signals, there are no external signal inputs - so it is less a collection of tubes and more a self-oscillating state-machine.

More info

 

'Alice'


Respond below.
No email addresses are collected for marketing purposes from responses to this blog.
I will keep it that way for as long as possible.

April 21, 2010

An Engineer in Wonderland - Hats off to volcano engineers

Volcano detail.jpgWhile some politicians attempt to score their pathetic points, declaring how they would have got aircraft moving more quickly without explaining how, engineers and scientists have worked hard to craft a set of rules for aircraft flying through ash plumes.

Continue reading "An Engineer in Wonderland - Hats off to volcano engineers" »

April 20, 2010

An Engineer in Wonderland - Tin opener obsession?

Tin opener2 web.JPGAlways nice to see a thoughtful piece of design, wherever you find it.

I came across another neat tin-opener this weekend - the first was the classic P-38.

This one seems to be designed with safety in mind as it cuts through the thick part of the rim and at the same time rolls away the sharp edges - my photo sadly doesn't really do the result justice.

Tin opened2 web.JPGWhile I wouldn't run my fingers along the resulting edges deliberately, they are nothing like as sharp as edges left by openers I have come across before.


'Alice'

If you wish, scroll down to respond.

 

No email addresses are collected for marketing purposes from responses to this blog.

I will keep it that way for as long as possible.

Continue reading "An Engineer in Wonderland - Tin opener obsession?" »

March 29, 2010

An Engineer in Wonderland - Tsunami generator

Tsunami generator.JPGI had assumed that almost everything was simulated in computers these days, but aparently not as the EPSRC (Engineering and Physical Sciences Research Council) has just paid for a wave simulator with real sloshing water.

It seems that a new facility is needed to simulate the dreadful 2004 Boxing Day tsunami.

Photo: Tsunami generator before being lowered into the water. Horizontal baffles stop sloshing inside the tank for a cleaner wave.

Continue reading "An Engineer in Wonderland - Tsunami generator" »

March 26, 2010

An Engineer in Wonderland - Revealing touchscreen review

Take a look the capacitive touch screen test on the website of development firm Moto.

iPhone comes out particularly well - its precision looks as good as a resistive touch screen.

Motorola's Droid does not fair so well.

And there are plenty of examples in between.

All the touch screens look pretty good for handling square touch buttons.

But some of them would be awful for sketching, and pretty bad for dragging and dropping.

'Alice'

Respond below if you wish
No email addresses are collected for marketing purposes from responses to this blog. I will keep it that way for as long as possible.

March 22, 2010

An engineer in wonderland - BT Broadband annoyance

Having resisted it for a long time, I have had broadband installed at home.

I thought long and hard about who would supply the service.

Any company with a bad reputation for service or reliability was straight off the list. 

Eventually I whittled it down to a shortlist:

Continue reading "An engineer in wonderland - BT Broadband annoyance" »

February 8, 2010

An Engineer in Wonderland - More push button bistables

More push by Mike thumb.JPGFollowing my trials and tribulations with seemingly-simple push button bistables, Mike M contacted me with some simpler ideas to the same end.

The application demands that two selectable leds to replace one, with any added circuit drawing power from across the driven led.

Continue reading "An Engineer in Wonderland - More push button bistables" »

February 1, 2010

An Engineer in Wonderland - Incongruous components lurk in my calculator

Calculator out tiny2.JPGI had to take a calculator apart this weekend, and inside I found a glass-package diode and an led with no light path to the outside world.

Continue reading "An Engineer in Wonderland - Incongruous components lurk in my calculator" »

January 29, 2010

An Engineer in Wonderland - And now the pcb

mark6.1pcb thumb.JPGInitial debugging complete, I knocked up a pcb in the kitchen.

I used CadSoft's wonderful free Eagle layout editor to design the board.

Continue reading "An Engineer in Wonderland - And now the pcb" »

January 27, 2010

An Engineer in Wonderland - Hysteresis mystery solved, probably

Mark 6.1 crop.JPGI think I have got to the bottom of the 74HC74 hysteresis mystery

The one that meant my LED-controlling bistable switch was not switching properly.

Continue reading "An Engineer in Wonderland - Hysteresis mystery solved, probably" »

January 25, 2010

An Engineer in Wonderland - Two leds for one

circuit.JPGThat push button bistable I have still yet to get going is part of an attempt to replace an led in an existing lamp with a choice of two.

I thought I would reveal the rest of my circuit for scrutiny.  

The idea is that the whole circuit connects directly into the lamp instead of the existing led, stealing a few microamps to run itself.

Continue reading "An Engineer in Wonderland - Two leds for one" »

January 22, 2010

An Engineer in Wonderland - A 74HC74 hysteresis mystery

74HC74small.JPGThe development 'lab' has moved to the kitchen table as the workshop is so cold that there is liquid nitrogen sloshing around on the floor.

And as well as my 'scope, Dr Frustration appears to be in the house.

For two evenings I have been trying to fault-find a breadboard circuit with only four components that is so trivial I almost didn't try it.

And am not even sure I am at the bottom of it yet.

Continue reading "An Engineer in Wonderland - A 74HC74 hysteresis mystery" »

January 20, 2010

An Engineer in Wonderland - Anglo-Saxon metrology rules your feet

In mindlessly browsing Wikipedia after my last blog on metrology, I came across something that I am hoping is true

 

In this article on English units of measure, it claims that the length of a barley seed - a barleycorn - was once the standard from which English measurement was derived, and that it is still in use.

Continue reading "An Engineer in Wonderland - Anglo-Saxon metrology rules your feet" »

January 18, 2010

An Engineer in Wonderland - Measuring one metre

I take my hat off to those who have to measure to extreme accuracies.

I came across slightly long winded but interesting paper on a US website that shows just what a bugger it is.

Continue reading "An Engineer in Wonderland - Measuring one metre" »

January 15, 2010

An Engineer in Wonderland - Train pick-ups and snow

Train pickups.jpgGot stuck on a train in the snow a week or so ago

The driver was great.

He told us exactly what the problem was, and exactly what he was going to do about it, and then he did it.

The problem was that the live rail was icy and the pick-up could not get enough power.

Continue reading "An Engineer in Wonderland - Train pick-ups and snow" »

January 7, 2010

An Engineer in Wonderland - Hopping robot

hopping robot small.jpgThose clever robot designers at Boston Dynamics in the US, together with Sandia Labs, have created a shoe box-sized vehicle that can jump over obstacles 7m high.

For military use, and intended to be finished this year, the Precision Urban Hopper can jump over or on to as many as 30 obstacles that are 40-60 times its own height.

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January 5, 2010

An engineer in wonderland - caving lamps

Caving lamp2crop.jpgEarly last year I took a look at a Cree led - Ledil lens combination and mentioned that it looked like a good basis for a caving lamp.

I also said that I would hesitate to make such a lamp in view of the consequences should it break deep underground.

At the time, a real caver responded
 - a caver who makes caving lights, no less.

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November 11, 2009

An Engineer in Wonderland - Arduino and brake lights

Arduino.jpgArduino is intriguing.

It is a simple cheap development system, including microcontroller hardware, for developing processor-based control systems.

I have never used such a thing, for my imagination ends at BASIC and assembler coding, but it looks likes with Arduino you could string a programme together pretty quickly without having to learn how which bits in the ADC do what (said Alice bitterly).

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October 20, 2009

An Engineer in Wonderland - Neat tiny scope

Sometimes it is hard to get control of that I want, I want, I want feeling.

And I had such a struggle when the CEO of drum-less drum kit company MidiSticks pointed me at this gorgeous miniature digital scope - for about £50.

Scope3.jpg

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October 15, 2009

An Engineer in Wonderland - Jewel of an engine

smallest inline engine.jpgSent in by a reader, there is a marvelous internal combustion engine to be seen over on TechEBlog.

http://www.techeblog.com/index.php/tech-gadget/mechanic-builds-smallest-inline-4-engine-ever

Claimed to be the smallest in-line four yet, it sounds delightful.

'Alice'

Respond below, or to alice@electronicsweekly.

September 17, 2009

An Engineer in Wonderland - Digging up a surprise

Muddy watch.JPG Some while ago I confessed to being a fan of the Casio W-59 watch.

And by a complete coincidence, or a yet-to-be understood facet of quantum mechanics, I dug one up in the garden the other day.


 

Continue reading "An Engineer in Wonderland - Digging up a surprise" »

September 10, 2009

An Engineer in Wonderland - Hunt for a mosfet driver 2

Way back in November last year I was looking for a mosfet driver that would drive a top p-fet and a bottom n-fet so that I could run a half-bridge at 100% duty cycle.

Despite helpful replies from both Jeremy and Yilcan Guzelgunler, I got nowhere.

And so, heroically, gave up.

Continue reading "An Engineer in Wonderland - Hunt for a mosfet driver 2" »

September 4, 2009

An Engineer In Wonderland - Cunning packaging

package open.JPGCall me boring, but I quite like packaging.

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August 21, 2009

An Engineer in Wonderland - Wireless charging nonsense

Wireless Power.jpg

I neither like or dislike the idea of wireless charging, providing it does not fill up my house with strong magnetic or electric fields.

However, I don't like misleading comparisons.

Continue reading "An Engineer in Wonderland - Wireless charging nonsense" »

August 14, 2009

An Engineer in Wonderland - Sea urchin teeth

cc sea urchin.jpg

Given that survival requires nibbling a hole in rock, what kind of teeth do you need?

Quite complex and innovative teeth, it turns out.

Sea urchins hide in DIY limestone holes.

They have five teeth which, like those of rats, grow throughout the animals' life.

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August 12, 2009

An Engineer in Wonderland - A worthy wall chart

energy-use_tiny.jpgIn the same way that Harry Beck's 1931 Tube map simplified navigating the London Underground, the Lawrence Livermore National Laboratory has just released a rather interesting chart that summarises US energy consumption.

Continue reading "An Engineer in Wonderland - A worthy wall chart" »

August 10, 2009

An Engineer in Wonderland - A universal cloth

UniversalCloth.JPGWhen I used to go backpacking, I would put all sorts of cloths in my rucksack.

There would be at least: a towel, a flannel, something to wipe mud off the groundsheet, and something to wash up with. 

Over the years, I just managed to cut down the towel size to save space.

But since a foray into the kitchen department of a supermarket, I have reduced the camping cloth count to one.

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August 6, 2009

An Engineer in Wonderland - That bridge again

 

RoyalAlbertBridge.JPGI actually went and visited by Isambard Kingdom Brunel's Royal Albert Bridge, mentioned in another blog, that carries the main railway between Devon and Cornwall.

RoyalAlbertBridgeCloser.JPGEven to an untrained eye like mine, the mechanics look fairly straight forward, except for the diagonal beams from the chains to the main deck, and the curiously complex joints.

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August 4, 2009

An Engineer in Wonderland - spatial languages

I almost could not believe my ears last night.

Good old Radio 4 provided me with another revelation.

Apparently, about a third of the world's languages have no concept of left and right.

Continue reading "An Engineer in Wonderland - spatial languages" »

July 16, 2009

An Engineer in Wonderland - DAB nightmare

Alexandra Palace mast.jpg

I use my DAB radio every day.

And I just bought another one, for my workshop.

So I must be a fan. 

Or at least not a detractor.

Continue reading "An Engineer in Wonderland - DAB nightmare" »

July 14, 2009

An Engineer in Wonderland - Bridges I have known

second severn crossing.jpg

I like bridges.

For example, between junctions 11 (A320) and 12 (M3) on the M25 is a brutal-looking cable stay bridge that carries the Chertsey to Virginia Water railway.

It is a magnificent thing, all concrete and steel. 

It looks like the one that got out of the civil engineers design office before the architectural consultant could stop it. 

I can imagine the instruction: "Sod what it looks like, just make it STRONG".

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July 1, 2009

An Engineer in Wonderland - High visibility pedestrian railings

Every time I see these things I am impressed with the elegance of the idea.

cunning railings 2.JPGSome clever soul thought of off-setting the vertical infill bars in the pedestrian guard railings near crossings in such a way that kids were visible through the railings before they ran out across the road.

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June 17, 2009

An Engineer in Wonderland - 180mA leakage

A friend of mine was having a car flat battery problem.

It turned out to be the car radio which, when 'off', drew 186mA.

That's 2W!

Continue reading "An Engineer in Wonderland - 180mA leakage" »

June 15, 2009

An Engineer in Wonderland - Mechanical entangle

MechanicalEntangleLite.jpgI don't understand quantum entanglement - Einstein's 'spooky action at a distance' - but I am amazed by it and for no particular reason am pleased that it seems to exist.

I though it was restricted to photon and sub-atomic stuff, but it appears that a mechanical version is also possible.

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June 12, 2009

An Engineer in Wonderland - 10 million tonnes of rock

New Zealand.jpgLiving in the UK, you get a certain view of things which leads to surprises when you go to other countries.

For example, the UK is largely stable geologically, and not very steep.

This contrasts with New Zealand which is both steep, and a bit lively on the tectonic front.

Cycling around that fine country a while ago, I got invited in for a coffee by a retired guy who turned out to be: a, very interesting and; b, mostly mad.

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June 10, 2009

An Engineer in Wonderland - The Space Shuttle Shop

Several years ago, I used to go to visit Staines in Middlesex (or not in Middlesex - depending on whether you are a Post Office or County Boundary pedant).

Once there, I used to get involved with repairing things and frequently had to buy odds and sods locally.

There were diy sheds in the area, but the local independent diy shop was so good that I seldom even bothered to try the big chain stores.

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June 9, 2009

An Engineer in Wonderland - Mystery boxes

mystery object lite.JPGI found this, and things like this, in Scotland.

Each time, they were in pairs, one on either side of a path in the mountains.

My guess is that they detect the passage of people along the path, possibly by microwave.

But the answer could be much simpler.

Does anyone know for sure what they are, what they do, and how they work?


'Alice'

Respond below, or to alice@electronicsweekly.com

June 5, 2009

An Engineer in Wonderland - the glory of reed switches

I was pondering the failure of my car roof light to operate, wondering if newer cars had gone beyond the corrosion-prone two-pieces-of-metal-and-a-bit-of-plastic door switch.

When reed switches came to mind.

For the uninitiated, these consist of two flat flexible magnetic wires - reeds - held parallel and overlapping in a sealed glass tube.

Continue reading "An Engineer in Wonderland - the glory of reed switches" »

May 27, 2009

An Engineer in Wonderland - Is there a TV with...

histogram.jpg
This is the fourth occasion where the TCE2001 set-top aerial from Telcam has worked for someone I know.

This time it was for Electronics Weekly's bon vivant David Manners, and he was so grateful that he bough me a bottle of Champagne.

Good man.

I first came across the aerial in a Which report and, while I am not claiming it to be a miracle product, it does seem to be a proper broadband log-periodic design that pulls in digital TV signals where there is a good signal. And there is an optional amplifier in the box as well.

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May 20, 2009

An Engineer in Wonderland - Digital gear indicator inspiration

digital gear circuit thumbnail.jpg

Some motorcycles have digital gear indicators, some of which work by grounding one of five contacts depending on what gear you are in - plus one for neutral.

For the record, others use a potentiometer, and some after-market versions calculate the gear after measuring engine revs and wheel speed.

I was googling gear indicators and came across this circuit to interface such switches to a seven segment display. 

It is classical digital approach to the problem, with three logic chips and a regulator.

Continue reading "An Engineer in Wonderland - Digital gear indicator inspiration" »

May 8, 2009

An Engineer in Wonderland - A neat one-way valve

clappers.jpgI was cheering on some friends at the London Marathon, and for the first time paid some attention to those stick-shaped balloons that kids bang together to make a noise - most litter bins had at least one pair in.

They are made of not-particularly-stretchy plastic - polyethylene I think - and are blown up hard enough to make a noise a bit like a drum - a thankfully quiet drum - when you hit them.

The valve is simply some more of the skin material formed into a tube and stuffed inside one end. The only closing force appears to come from internal air pressure.

Continue reading "An Engineer in Wonderland - A neat one-way valve" »

May 7, 2009

An Engineer in Wonderland - Building a more interesting mouse trap

mouse trap.jpg

There was a drawback to thoroughly removing the nasty old glass insulation from my loft and replacing it with nice safe polyester fluff.

Rodents have moved in.

It may just be a coincidence, but when I took out the mineral wool there were only a couple of birds nests in the loft and not a sign of a mouse.

Now I hear little feet scurrying around at night, and things are starting to get chewed.

Continue reading "An Engineer in Wonderland - Building a more interesting mouse trap" »

May 6, 2009

An Engineer in Wonderland - Water tanks, water bottles, and safe insulation

WaterTank.JPGLittle did I know when I was uncharacteristically thorough a couple of months ago and inspected my cold water tank that a world of new materials would be unveiled.

It turned out to be rusted all the way through at one point - if yours is anything like 50 years old, check it tonight.

If you find a patch of rust on the outside, don't even touch it with your fingers.

Once mine was drained, I easily pushed a screwdriver through. There was no metal at all.

Continue reading "An Engineer in Wonderland - Water tanks, water bottles, and safe insulation" »

April 29, 2009

An Engineer in Wonderland - an eye with reflective focussing

06may09spookFish.jpgAs far as I knew from school biology, eyes are either compound or simple, and it is taken as read that they focus refractivly.

Now it turns out they can be a little bit compound, and incorporate reflective focussing.

Continue reading "An Engineer in Wonderland - an eye with reflective focussing" »

April 28, 2009

An Engineer In Wonderland - A thoughtful energy book - free!

TalismanWindmillThin.JPGI am a Radio 4 fan, and once again it has come up trumps.

On More or Less - a programme about numbers - it drew my attention to a book on sustainable energy by David MacKay, a Cambridge professor who said he wanted to get to the bottom of the world's energy balance, and did, and he wrote it all down.

The book is called 'Sustainable Energy - without the hot air', and can be bought in paper form or, most generously on the part of MacKay, downloaded for free as a .pdf.

 

 

 

This is one of two 5MW deep water wind turbines constructed by Talisman Energy (UK)

 

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April 7, 2009

An Engineer In Wonderland - A is for Air

blue sky.jpg

I was playing I Spy the other night and failed to guess that A stood for Air.

I protested that you can't see air.

But it was pointed out that heat haze and twinkling stars are a result of refractive index variations, so therefore you can see air.

Which got me pondering, as G for Glass is probably legitimate in I Spy.

So now I can cannot decide, in any scientifically defendable way, whether A for Air is cheating or not.

Or maybe I am not supposed to take I Spy so seriously.

'Alice' - a pedant who suffers in a world of inexactitude

Reply below, or to alice@electronicsweekly.com


An Engineer in Wonderland - Greenbird

Greenbird2.JPGTurns out that Her Majesty's subjects have broken yet another land speed record - this time the wind powered one - in a rather nice looking vehicle.

From the press release:

On the morning of March 26th, on the dry Lake Ivanpah, the Ecotricity Greenbird driven by British engineer, Richard Jenkins smashed the world land speed record for wind powered vehicles.

The Greenbird clocked 126.1 mph (202.9 km/h), eclipsing the old, American held, record of 116 mph , set by Bob Schumacher in the Iron Duck in March 1999 at the same location.


It also looks like the same team is going to try it on ice.

Good luck gentlefolk

'Alice'

Ps, there is a bit more information here.

Respond below, or to alice@electronicsweekly.com

April 6, 2009

An Engineer in Wonderland - Stopwatch dexterity

stopwatch.JPGI went on a course this weekend to allow me to help out at athletics events as a bottom rung official.

The first thing I learned was that there is so much more to the job than I thought there would be, so hats off to anyone who gives up their time, usually for free, to do this stuff.

The second thing I learned was that everyone who had already had a go at officiating has stories of school events where angry parents have marched up to them to either argue about, or even corrupt, a judgement.

Continue reading "An Engineer in Wonderland - Stopwatch dexterity" »

April 2, 2009

An Engineer In Wonderland - A day in the Science Museum

exterior_of_museum jpg.jpgI never tire of the Science Museum in London.

I can tramp the halls for hours without finding anything too dry to be of interest.

And I have spent a very long time in front of a cabinet in the locksmithing gallery getting more and more frustrated at failing to fathom one - or, to be honest, any - of the mechanisms behind the glass.

But this time I had a whole new experience there: Fun.

Continue reading "An Engineer In Wonderland - A day in the Science Museum" »

March 26, 2009

An Engineer in Wonderland - A most unusual satellite.

26mar09GOCEsmall.JPG

GOCE is an unusual satellite - the one that was launched recently to measure gravity accurately.

Most unusually, it is an aerodynamic satellite because it flies low at 250km altitude where there are still a few air molecules.

 

 PICTURE - GOCE is 5m long, weighs 1,100kg, and its chassis is carbon fibre

Its solar cells are stuck on the outside like old-style satellites rather that being on steerable wings, both because drag is less this way, and it can't afford to be vibrated by steering motors.

In fact, it can't afford to be vibrated by anything.

Continue reading "An Engineer in Wonderland - A most unusual satellite. " »

March 25, 2009

An Engineer in Wonderland - LTM8020 and soldering frustration

01Apr09SolderingHell.JPG I came across the LTM8020 dc-dc buck converter and thought it would be ideal for charging the Mark V bike light Li-ion battery.

 

Continue reading "An Engineer in Wonderland - LTM8020 and soldering frustration" »

March 24, 2009

An Engineer in Wonderland - Cold fusion

01apr09ColdFusionLite.jpgI want cold fusion to work because I like the idea of easy energy for free.

But when evidence for it was first claimed, no one could repeat the results and the overall effect was worse that a damp squib.
It made scientists look a bit mad.

 

PICTURE - The US Navy says these three tracks are evidence of cold fusion

Continue reading "An Engineer in Wonderland - Cold fusion" »

March 23, 2009

An Engineer in Wonderland - Bursting capacitors and humility

BlownCap.JPGOccasionally, the workshop RCD used to trip and I could never find out what was causing it.

In my defence, I did look over the whole lot and made sure there was no water in anything, and everything looked sensible.

It only ever happened after a couple of hours of use, and when workshop heater was set to 2kW.

So for want of something more intelligent to do, I blamed the RCD which is of the plug-in type and which naturally runs fairly warm.

Continue reading "An Engineer in Wonderland - Bursting capacitors and humility" »

March 20, 2009

An Engineer in Wonderland - Inventing the 555 and the 741

I was trawling the archive of Electronics Weekly, and came across an article from November 16th 1996.

It describes the invention of two famous analogue chips - the 741 and the 555.

Just in case you are interested, as it doesn't seem to be available from the website, I have included the full text below.

Enjoy

'Alice'

Continue reading "An Engineer in Wonderland - Inventing the 555 and the 741" »

March 4, 2009

An Engineer in Wonderland - An 0.7V microcontroller

0.7VmpuLast year around this time, Silicon Labs introduced C8051F9xx - a microcontroller family capable of operation down to 0.9V, and up to 3.6V.

The core does not actually run at 0.9V, there is an in-built boost converter.

Atmel has gone one better, or maybe just 0.2 better, and come up with an MPU that works down to 0.7V.

Continue reading "An Engineer in Wonderland - An 0.7V microcontroller" »

February 27, 2009

An Engineer in Wonderland - Led headlights - de-dazzling the beam

IQfly.JPGInspired by comments made on one of the Electronics Weekly blogs, I thought I would have a go at estimating which led-collimators combination would not dazzle on-comers if used in a vehicle headlight.

A dazzle-free beam must be possible, because the IQ Fly pictured here can do it.

Now, I have to admit that I am winging the calculations here - so any corrections or refutations to the following are welcome.

Continue reading "An Engineer in Wonderland - Led headlights - de-dazzling the beam " »

February 18, 2009

An Engineer in Wonderland - Thermoelectricity and photons

25feb09NextremeShrunk.jpgTo be fair, I cannot say I know as much about photons as an earth worm because I have no idea how much worms know about quantum physics.

So instead I will say I know almost nothing about photons*.

This has not stopped me being puzzled by this article

 

Continue reading "An Engineer in Wonderland - Thermoelectricity and photons" »

February 17, 2009

An Engineer in Wonderland - The Mk V prototype takes shape

temp.jpgThree nights in a freezing shed, and finally an LED light sits on the front of a bike at Alice Towers. Following the over-heating disaster, I chickened out of soldering the re-made parts of the Mk V together and this time glued them with Arctic Alumina Adhesive.

Continue reading "An Engineer in Wonderland - The Mk V prototype takes shape" »

February 13, 2009

An Engineer in Wonderland - LEDs and lenses - a reality check

Electronics Weekly sometimes requests device samples.

It is not that the team doesn't believe the specifications we are sent every day, it is just that it can be tricky to put 77dBA or 33 lm into perspective.

18feb09Cree3shrunk.JPGThe latest items to arrive in the post are a Cree MC-E power LED development board and some matching Eva collimators from Finnish lens maker Ledil.

The specifications are on the respective web sites, but what are the devices actually like?

Continue reading "An Engineer in Wonderland - LEDs and lenses - a reality check" »

February 12, 2009

An Engineer in Wonderland - Cornflour heaven

Cornflour 2.jpgAlong with a visitor last night came her son.

And along with the son came a jar of gunk which reminded me of the cornflour and water mix I played with years ago.

And what pleasure, it was cornflour and water.

For the uninitiated, this stuff behaves in a very odd way and will keep kids and the odd engineer entertained for hours.

When poured and stirred slowly, it is a liquid.

When thumped, it momentarily becomes a solid.

If you hit is hard enough, it will actually shatter before turning back into drops of liquid.

Continue reading "An Engineer in Wonderland - Cornflour heaven" »

January 29, 2009

An Engineer in Wonderland - A bag for explosions

liposafebag.jpgLithium ion and lithium polymer cells are wonderful, because they store lots of energy and don't weigh very much.

But as pointed out in Electronics Weekly more than once: if abused, they can bite back.

Over-heating, over-charging, over-discharging, penetration, crushing, and probably just being Tuesday can turn them into a fire ball in a second or so.

I remember someone on a caving discussion forum declaring that he had made a head lamp and its lithium polymer cells resided inside his caving helmet....

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January 16, 2009

An Engineer in Wonderland - Free LED design software

nat semi webinar.jpgThe second of Nat Semi's excellent power led seminars 'Driving High-Power LEDs Without Getting Burned - Part 2' includes some good stuff about the feedback stabilisation inside buck regulators driving power leds and also a couple of demonstrations of free design software available.

The thermal design tool is tied to Future/Lumileds and the electrical design software is National's own, but I am guessing both will at least show you what is possible, could be used to get the feel of power led design, and would be a way to do some suck-it-and-see work before getting out the soldering iron.

Does anyone know of any other free power LED tools out there.

'Alice'

Respond below, or to alice@electronicsweekly.com

You cannot get spammed for replying to either.
 - That is the way it should be. 

January 12, 2009

An Engineer in Wonderland - Soldering aluminium, triumph and tragedy

easy weld.jpgApart from school, and two weeks at college on a course, I have no idea how to use a lathe.

But over Christmas I found a few days to lock myself away with a small one and gradually made a pile of parts for my Mark V bike light.

I suspect the tolerances I achieved would make a toolmaker giggle, but I was proud that the bits fitted together at all.

This weekend I attempted to solder them together using special aluminium solder from Durafix.

To see what an expert can do, take a look at the videos on the site.

Continue reading "An Engineer in Wonderland - Soldering aluminium, triumph and tragedy" »

January 8, 2009

An Engineer In Wonderland - Metal detecting with an 8 pin micro

cc gold bar.jpgSometimes I am amazed by the ingenuity of a circuit.

I had such a moment when I first saw a 1997 application note for the PIC12C series of 8 pin microcontrollers called 'Using PIC12CXXX as a Sensor Interface for Metal Detection' by Vladimir Velchev of Bulgaria.

An entry for Microchip's 'Designing for Dollars' competition.

The very clever bit is that Velchev cunningly replaces the microcontroller's external crystal with a parallel LC tank circuit, where the L is the coil of a metal detector.

This means the processor clock frequency is determined by the coil inductance, which is affected by nearby lumps of metal.

Continue reading "An Engineer In Wonderland - Metal detecting with an 8 pin micro" »

December 8, 2008

An Engineer in Wonderland - Statistics are like sharp things (idiots should not be trusted with them)

cc stats generic - twitter stats.jpgSee all 'Engineer In Wonderland' posts

Some things drive me to fist-clenching frustration, bordering on despair.

A remarkable amount of this happens to me when I hear what politicians do when they are trusted with statistics.

A few years ago I was up in the far north of Scotland, in a cafe next to Loch Eriboll.

By the way, if you have a small motorcycle, I reckon the road up the west side of this Loch is the best in the UK.

Anyway, I was chatting to a local small-scale commercial fisherman who said he had given up trying to catch fish and gone over to lobsters - or crabs, I can't remember which - after he saw a huge ocean-going trawler come into the loch in a desperate search for a catch.

Continue reading "An Engineer in Wonderland - Statistics are like sharp things (idiots should not be trusted with them)" »

December 4, 2008

An Engineer in Wonderland - Charger power waste. Did they miss a trick?

nokia power consumption star chart.jpgSee all 'Engineer In Wonderland' posts

Call me fussy, but I do not like designs that throw away power.

Particularly designs that consume stand-by power.

High stand-by power, even if it is to save a few pence in manufacture, is sloppy design.

Some big players in the mobile phone industry:  LG Electronics, Motorola, Nokia, Samsung and Sony Ericsson recently got together to come up with a star rating for charger standby consumption.

The ratings are:

* * * * *     = 30mW
* * * *     > 30 to 150mW
* * *     > 150 to 250mW
* *     > 250 to 350mW
*     > 350 to 500mW
No Stars > 500mW

Don't get me wrong. This is a fine idea and should be applauded - if only set-top box makers could get anywhere near this.

Continue reading "An Engineer in Wonderland - Charger power waste. Did they miss a trick?" »

December 3, 2008

An Engineer in Wonderland - You want magnetics how fast?

TDK museum.jpgSee all 'Engineer In Wonderland' posts

TDK knows a lot about magnetics, having been set up in 1935 as the world's first commercial producer of the stuff.

A few years ago, I can remember standing by a TDK engineer when he heard that a 2 or 3MHz (I can't remember which now) dc to dc converter chip had been introduced.

"Are you sure?" he asked incredulously.

He went on to say that, although raising frequencies was great for reducing size, efficiency could suffer when you push magnetic materials so far up the spectrum.

But if anyone could make ferrites efficient at 3MHz, TDK could - and probably already had, somewhere in its vast organisation.

Fast forward - and I can imagine eyebrows were once more raised in Japan when Analogue Devices recently introduced the ADP2121, a buck regulator that is designed to operate at a stunning 6MHz.
 

Continue reading "An Engineer in Wonderland - You want magnetics how fast?" »

November 28, 2008

An Engineer in Wonderland - Mosfet driver

Alice fig 1.jpgSee all 'Engineer In Wonderland' posts

Have you ever had the feeling that you are the first person ever to want a certain building block?

There are a lot of different half-bridge mosfet drivers in the world, but almost all are designed to drive two n-mosfets.

This means that the top mosfet's gate drive comes from a bootstrap circuit, which in turn means the half-bridge can never operate at 100% duty cycle.

I want 0-100% to build a bit of test gear, and so have been hunting for a half-bridge driver that will drive a p-channel mosfet at the top, and an n-channel below - at voltages from 4 to 20V, from a logic input.
 

Continue reading "An Engineer in Wonderland - Mosfet driver" »

November 26, 2008

An Engineer in Wonderland - Led Christmas lights

cc xmas led lights.jpgSee all 'Engineer In Wonderland' posts

I was rigging up some Christmas lights and in a fit of enthusiasm thought that flashing would be good.

So I drew out a multivibrator, then wondered what other two transistor circuits would also flash some lights.

Mr Google delivered this rather good site which gives chapter a verse on the subject of two transistor oscillators.

The disappointing part was, it looks like the good old standard circuit best suits my needs, so no exotic new oscillator to play with.

I have 20 parallel red leds, and 20 parallel blue leds, and a source of constant current.

Continue reading "An Engineer in Wonderland - Led Christmas lights" »

October 31, 2008

An Engineer In Wonderland - Copying Geckos

baby gecko.jpgSee all 'Engineer In Wonderland' posts

I am fascinated by the potential of biomimetics.

Years ago I fell into conversation with an academic biologist.

He told me that if you want to make stuff, find an enzyme to do it because enzymes, which are nature's catalysts, do things very well - generally far more effectively than simple chemicals or thermal processes.
 
They work by pushing just the right electro-chemical buttons to make reactions happen - putting a key in the lock rather than breaking the door down.

Enzymes cannot be designed from the ground up for specific tasks at the moment because most of them are proteins and 'the protein folding problem' - what shape any given protein will end up, and where its charges will be - has yet to be solved.

This is not because no one knows how to do it, but because there isn't enough free computer time in the world to have much of a stab at it.

IBM's original Blue Gene supercomputer was specifically designed to model protein folding.

Destined to be the most powerful computer ever made, it seems to be one of the great IBM 'hey, this would be interesting and might do a lot of good' projects.

Continue reading "An Engineer In Wonderland - Copying Geckos" »

October 22, 2008

An Engineer in Wonderland - Lock ignorance and a frightening revelation

snapsafe_before.jpgSee all 'Engineer In Wonderland' posts

It turns out that I know nothing about locks. At least I didn't until last Friday when I resorted to Mr Google. And now I am worried.

I am building a door for a shed which I want to be secure, and got to the what-shape-hole-do-I-need-for-the-lock bit.

So I went to a couple of DIY stores and came back without a lock, and knowing that I have never really thought through the subject before.

Hence Google.

With apologies to those who have known this all their lives, this is what I learned: - The worrying bits are at the bottom

What ever lock I chose has to include a 'deadlock' as deadlocks can only ever be opened with a key.

A sash lock includes a deadlock, but also a spring-loaded bolt and a handle so the door stays shut on a windy day but can be opened with the handle when not deadlocked.

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September 25, 2008

An Engineer in Wonderland - A 74HC4060 monostable?

4060logic.jpgSee all 'Engineer In Wonderland' posts

I have always been a great fan of the 4000 CMOS series, and its 74HC derivatives.

So when an engineer friend of mine was mulling over options for a five minute delay circuit, I chipped in that I thought the 4060 14-stage ripple counter and oscillator should be able to do it.

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September 24, 2008

An Engineer in Wonderland - A watch for all seasons

W59Lite.JPGSee all 'Engineer In Wonderland' posts

Those that buy watches with hands, in my opinion, are fashion victims.

If the designer of the first watch had had access to digital technology, I am fairly sure he or she would have gone straight to digits.

And those with too much money buy mechanical watches.

It impresses me that firms still design mechanical watches - and it pleases me that those that buy them support a thriving and innovative niche engineering industry.

So if you have lots of money, please buy an expensive mechanical watch.  

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An Engineer in Wonderland - Strange aerials on La Palma

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I know my place, and realise that aerial design is not for me and must be left to those with pointy hats and wands.

So could one of those good folk tell me what this kind of aerial is and why it is better than the traditional Yagi-Uda or log-periodic.

They were spotted on many houses on the Canary Island of La Palma, all pointing east - possibly towards the larger island of Tenerife - and mostly pointing slightly upwards.

'Alice'

Respond below, or to alice@electronicsweekly.com

September 9, 2008

An Engineer in Wonderland - A tea break challenge to you

BikeLightMT470.jpg For the purposes of clarity I have to reveal at this point I occasionally make dynamo-powered bicycle lights, and that the last two An Engineer in Wonderland entries are parts of this winter's planned front light: the Mark V

Eventually the whole thing will be linked up by a microcontroller, but as I have yet to finish testing a surprisingly large amount of code - I finally rewrote the whole thing using a state-machine rather than the rat's nest of flags that graced the MkII.

So I need a nice simple hardware controller to road test the analogue bits now.

The criteria for input and output of the mystery box are:

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September 8, 2008

An Engineer in Wonderland - turning off an LM334-based led driver

LedDriver250.jpgI want to drive power led from a Li-ion cell.

I have a few specific requirements.

One is that the driver must tolerate a second current source feeding the led, and only supply current when the other source is under 250mA.

It should also not be blown up by this second feed.

And it should shut down to a few µA when switched off.

There do seem to be a few chips that can do this lot, but I thought I would try a home brew version.

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September 4, 2008

An Engineer in Wonderland - Li-ion charging with an LM317

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There are an awful lot of Li-ion charging chips out there, and you would have thought there was one for every eventuality.

But it turns out there isn't.

For example, there is a sort of no-designer's-land between 6.5V where linear Li-ion chargers top out - although Linear's LTC1734 works up to 8V - and around 12V where switching chargers start. 

And even without an input voltage restriction, what if you don't want to charge the thing at less than 4.2V?

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September 2, 2008

An Engineer in Wonderland - Measuring stuff in the steam age

For some foolish reason I automatically assume that precision was invented recently.

I am not quite sure exactly what year I think people started quantifying in parts-per-million.

But I am sure that I am wrong.

For example, I was wandering around the York National Railway Museum a year or so ago when I came across an unexpected treat....

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August 18, 2008

An Engineer in Wonderland - The Syphon of Eden

eden project.jpgA few years ago I went to the Eden Project in Cornwall.

It is a huge garden with enormous geodesic greenhouses (the largest in the world) in an old quarry.

It is great, go there, take the kids

However, for a place which wraps itself in the 'green' flag, it does consume a lot of stand-by power - several kW in fact.

Why?

Well, like most old quarries, it would quite like to have a lake in the bottom.

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August 15, 2008

An Engineer in Wonderland - LCDs get 'greener'

Fujitsu screen.jpgI have been agonising over buying a new computer monitor for ages.

There is a bewildering array available and the questions that need answering include:
  • 22" 1280x1024 or 24" 1680x1050?
  • Twisted nematic, in-plane switched, or some other technology?
  • A brand or a cheapie?
  • HD-ready just in case I ever watch DVDs?
So many questions, and so little decisiveness.

But I may have a way to cut the choice down - Alice's Razor is to be energy consumption. 

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August 8, 2008

An Engineer in Wonderland - Big Science

cern icon-velo-2008-001.gifI admire the search of knowledge for the sake of knowledge.

And I particularly admire it when lots of engineers get paid to design interesting and challenging stuff to support the science.

Which is why I was particularly impressed when a friend drew my attention to some pictures from the Large Hadron Collider under the boarders of Switzerland and France.

Wow - to the scale of the thing, and the courage of the vision that made it possible.

'Alice'

Reply below, or to alice@electronicsweekly.com

(Pictured: Three modules of the LHCb Vertex Locator in the H8 test beam in the North Area)

August 4, 2008

An Engineer in Wonderland - Roller clutches

roller clutch.jpgI am currently driving to work as my bicycle has a fault which is in danger of becoming a saga.

A long long time ago far far away, I bought a back wheel.

And within the back wheel was a novel freewheel mechanism based on a roller clutch rather than the standard pawl system that has served cycling well for a century.

A roller clutch is a bit like a roller bearing: It has two concentric cylinders, one inside the other, and between them are metal rollers.

The cunning bit is that, unlike a roller bearing, ramps cut into the surface of one of the cylinders - one ramp per roller- make the gap between the cylinders vary slightly above and below the diameter of a roller.

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July 31, 2008

An Engineer in Wonderland - Alice-machine interface

06aug08RadioOld2.JPGThese days, I own a car.

And as I have a car, I feel the need for Radio 4 and music.

So a year or so ago I replaced the standard worn cassette-radio with a CD-radio (left).

It cost £50ish from Lidl, and its major selling point was that it also played USB sticks and SD cards.

Incidentally, the necessary fitting kits, bought from Halfords, to convert Ford's non-standard radio orifice to fit a DIN standard radio cost almost as much as the new radio - thanks Ford.

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July 29, 2008

An Engineer in Wonderland - A car alternator surprise

AliceAlterator2.JPGI was asked to have a look at a car that was not charging properly yesterday.

It is a kit car based on a Renault 6.

When I measured the battery, it was charging at about 13.8V - with and without the lights on. This is a bit on the low side for a car, but acceptable.

As the owner said it had not been charging at all, I thought I would pull the alternator brushes, just in case they were worn.

So we took the thing off, a SEV Marchal unit, and dismantled the back end where the brushes normally are.

No brushes. 

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July 24, 2008

An Engineer in Wonderland - Madness in Battersea

30jul08BatterseaEM1 small.JPGBattersea power station in London, with its chimney at each corner, is an icon - not least for having made it onto the cover of Pink Floyd's Animals album and having been designed by Sir Giles Gilbert Scott - he of red telephone box fame.

There are plenty of other reasons to love the place, including a rather fine art-deco interior and it once having been part of a large CHP (combined heat and power) scheme that heated a housing development on the other side of the Thames.

But an odd thing is going down at the site, which has been derelict for years and is prime building land.

30jul08BatterseaEM2.JPGThe main building is well worth saving as is has two beautifully decorated cathedral-like spaces solidly built in brick - it is the biggest brick building in Europe.

However, those famous chimneys have to come down. They are fatally riddled with cracks - the result of an incomplete understanding of reinforced concrete when they were built.

Here comes the madness:

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An Engineer in Wonderland - portable toilets

portable toilets.jpgThere is something wonderful about portable toilets.

Not only because they are the difference between privacy and bearing your bum in public, but because the construction is so neat.

There are a few simple plastic mouldings, which I assume are vacuum or pressure formed from flat sheets on a single-side mould.

Then there are pop rivets

A few bent bits of metal for fittings

A hand pump

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