About LEDs

This page contains an archive of all entries posted to Gadget Freak in the LEDs category. They are listed from oldest to newest.

Japan is the previous category.

Light flashers/blinkers is the next category.

Many more can be found on the main index page or by looking through the archives.

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September 3, 2007

Build a 7x7 monochrome LED display

Here is the circuit schematic as well as build instructions and parts list for an easy to build 7x7 LED matrix.

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Continue reading "Build a 7x7 monochrome LED display" »

September 6, 2007

The not-so-bright LED night light

From our sister publication Made by Monkeys, a tale of what happened when engineer Dave Johnson felt ripped-off by the purchase of a cheap LED night light. He reconfigured the circuit and turned it into a much more expensive one – but at least it works.

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Continue reading "The not-so-bright LED night light" »

September 18, 2007

White-LED driver: I've got the power!

It seems the stage is set for world domination from the humble LED.

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Continue reading "White-LED driver: I've got the power!" »

September 24, 2007

When high fashion meets electronics engineering

At the height of her career, Marlene Dietrich – that famous woman in trousers – said, ‘I dress for the image. Not for myself, not for the public, not for fashion, not for men.’

In an age where skinny jeans reign, and thousands flock to Top Shop hoping to emulate the style icon Kate Moss, dressing for image is a given. After all, wasn’t former Givenchy svengali Alexander McQueen christened the ‘enfant terrible’ of British fashion?

Given the spirit of Gadget Freak, we present the work of British fashion designer Hussein Chalayan MBE. Born in Cyprus, the Central St Martin alumnus showcased his Spring Summer 2007 collection which featured a vast array of garments that require an electrical engineer to operate them via a specially designed remote control.

Continue reading "When high fashion meets electronics engineering" »

September 27, 2007

Rainbow LED indicates voltage with colour

Who says you can’t have fun with LEDs?

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Continue reading "Rainbow LED indicates voltage with colour" »

October 4, 2007

Fantastic atom expander

The fantastic atom expander produces an “exploding atom” effect using 98 LEDs.

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Continue reading "Fantastic atom expander" »

October 8, 2007

How to build a rotating LED display

Alan Parekh designed a rotating LED display.

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Continue reading "How to build a rotating LED display" »

October 18, 2007

White LED driver provides 64-step logarithmic dimming

This circuit for the white LED driver drives as many as four white LEDs from a 3.3V source and adjusts the total LED current from 1 to 106 mA in 64 steps of 1 dB each.

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Continue reading "White LED driver provides 64-step logarithmic dimming" »

November 2, 2007

Bill had that weird feeling he was being watched

Partial to things that go bump in the night, Bill built a circuit that slowly illuminates and fades a pair of red LEDs. It consists of two op amps, one producing a slow rising and falling voltage (3 - 6V) and the other functioning as a voltage comparator. In operation, a linear 3V ramping waveform is generated at pin 1 of the LM1458 IC and buffered with an emitter follower transistor stage. Make the rate adjustable by using a 100K potentiometer in place of the 47K resistor at pin 2. Install it in a skull as a Halloween prop or if spooky things aren't your thing, use it as a fancy power indicator for a home appliance.

Click the continue reading link for full build instructions, parts list, and circuit schematic.

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Continue reading "Bill had that weird feeling he was being watched" »

December 6, 2007

Jon knows how to spread Christmas cheer

Deck the halls with LEDs this Christmas

Tired of bobbing reindeer heads and inflatable snowman displays, Jon decided to add some real flash to his holidays. By combining a digital counter, decoder, drivers, and relays, he built a simple, yet flexible circuit that allows for exciting flashing patterns and sequences for a few or many light strings. Building the "flasher" on a solderless breadboard makes modifications easy.

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Continue reading "Jon knows how to spread Christmas cheer" »

January 30, 2008

Les wears his silicon on his sleeve

Looking for cool way of wowing that special someone on Valentines Day? Build her a flashing heart made from LEDs driven by a programmable microcontroller. Les' gadget is simple to build and made from easily-obtainable parts. The unique thing about this design is the LEDs are in an X-Y matrix so each LED is addressable. This allows an unlimited combination of displayed patterns for the heart. Source code and schematics are all available here and if you're not into hand wiring, even the PCB can be had for a small fee. Diamonds may be a girl's best friend but gadgets are forever.

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Continue reading "Les wears his silicon on his sleeve" »

February 13, 2008

Pete decided to give his lamp a facelift

Making an ordinary lamp a work of art

Seeing great potential in a normal, off-the-shelf product, Pete Griffiths designed a circuit he popped into the lamp to give it a new lease of life. His design combines a PIC and three constant current buck converters to create the RGB LED controller. This controller drives the high power 350mA LEDs using PWM to control the LED brightness. By driving the red, green and blue LEDs with varying pulse widths the controller can generate up to 16 million colours using fades, strobe and static effects. Who says you can't give the humble lamp a nip and tuck?

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Continue reading "Pete decided to give his lamp a facelift" »

March 26, 2008

Trip the Light Fantastic with LED Gadget Freaks

From their humble beginnings as little red dots that let the user know if household appliances are switched on, LEDs can now be ultra bright light sources capable of lighting up a room or illuminating the road ahead of a vehicle.

High performance LEDs are now being churned out from many manufacturers around the world like they’re going out of fashion.

Here is a collection of the best LED gadgets that have made themselves home in Gadget Freak.

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Continue reading "Trip the Light Fantastic with LED Gadget Freaks" »

April 2, 2008

Three new Circuit Design Ideas

Back to Bella Italia

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Check out three new Circuit Design Ideas that have been added to the site - examples to give you inspiration for designing your own circuits. And they have an international flavour...

Continue reading "Three new Circuit Design Ideas" »

April 7, 2008

Sixty-five competition entries and counting...

There have been 65 entries so far for the Gadget Freak competition, and we are still counting, so make sure you have a go!

All you have to do is answer a question based on the use of an RGB LED controller in one of our Gadget Freak blog posts.

Enter the competition (see the Terms and Conditions)

Pictured is the prize - a wind-up, solar-powered Freeplay EyeMax Self-Sufficient AM/FM Radio, which also includes a (small) integrated flashlight.

Freeplay wind-up radio

April 15, 2008

3D LED cube dazzles in amazing fashion

This little gem from gizmodo.com:

“Seekway has put together this spectacular 3D LED display, which is capable of displaying images in full 3D at an amazing 30 fps."

Continue reading "3D LED cube dazzles in amazing fashion" »

May 8, 2008

Super flashlight: When the humble torch just isn't enough

Thanks to Electronics Weekly’s Technology Editor for sending us this gadget.

The super flashlight, from the CandlePower Forums, received rave reviews from visitors to the website. Link includes parts list and build instructions.

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Continue reading "Super flashlight: When the humble torch just isn't enough" »

July 16, 2008

LED Jellyfish Mood Lamp

Jellyfish led.jpgWelcome to the "hypnotic, other-worldly appeal of the LED Jellyfish Mood Lamp".

This press release has just caught my attention - a light-hearted one for Gadget Freak, I thought.

How much of a challenge would it be to recreate such a device?... (The real challenge would be in circulating the jellyfish in an interesting manner, I think, rather than the lighting effect)

The ambient lighting device is described as having a "whisper-quiet" operation and features an auto-off safety function that kicks in after four hours of use.

Continue reading "LED Jellyfish Mood Lamp" »

August 15, 2008

Peter's F1 gantry start-lights race into position

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Peter Griffiths - the man who turned a lamp into a work of art - moves into pole position with the featured Gadget Freak for August.

Based around LED cluster modules and a microcontroller, the circuit drives F1-style gantry race start lights.

Who wouldn't want to be the race controller, with their finger on the starting switch?

Fully documented in terms of parts and the build process, Peter has provided loads of photos to help navigate construction. And for those of you who don't have access to PCB making facilities, there are photos of building the project on stripboard.

Continue reading "Peter's F1 gantry start-lights race into position" »

October 24, 2008

500 LED 'extreme flashlight'

          Here's one for a Friday afternoon - a homemade 500 LED 'extreme flashlight', or torch, as we would say. As well as its operation, the video covers the build process for this device with 50 watt power consumption at full power.

See also: Electronics Weekly's roundup of content related to LEDs, with a special focus on both white LEDs and coloured LEDs:

LED technology - White LEDs

LED technology - Coloured LEDs

LED technology - LEDs general

LED technology - LEDs Lighting


Continue reading "500 LED 'extreme flashlight'" »

October 28, 2008

Peter plots an LED UFO chaser

      Peter Griffiths - the man who made a lamp into a work of art and turned to LEDs for F1 gantry start-lights - returns with some LED chasing.

This neat little circuit provides 8 LEDs directly driven from the PIC along with a single mode control switch. The firmware described drives the LEDs with a 5 bit PWM signal providing each of the 8 LED channels with four levels of intensity; off, dim, mid, bright. 

A number of sequences are programmed into the firmware to provide some interesting visual effects and chase sequences, including the classic effect seen on the car in the Knight Rider TV series.

Peter says that the design is deliberately simple with each LED being directly driven from a PIC I/O pin.  This and the inclusion of an in-circuit programming header (ICSP) make the circuit ideal for teaching/learning introductory PIC assembly language programming.

However, he writes, if you just want a cool LED chaser without having to write any code, a ready written LED chaser program with fully commented source code and programmer ready HEX files is provided at the bottom of this page.

The circuit has been constructed on a PCB but can easily be built on strip-board, or a solderless breadboard.

Possible apps include an Xmas Tree Chaser and, bending the LEDs through 90°, you have a UFO chaser.


Continue reading "Peter plots an LED UFO chaser" »

November 4, 2008

Ultra-bright and ultra-durable LED bicycle lights

LED mintduo1.jpgAs the last glimpses of autumn sunshine begin to fade into the long dark nights of winter, those athletic gadget freak readers who avidly insist on cycling to work everyday are presented with a potentially dangerous problem.

When using a vehicle as fundamentally fragile as a bicycle it is incredibly important to both be seen and be able to see when travelling home at 6pm on a dark windy night sometime in late November.

Although bike lights are by no means a new invention and have been used successfully for years, the rapid evolution in LED design means increasingly more powerful and more durable lights can be manufactured.

Enter three bike light hobbyists from Australia who have taken particular advantage of this recent surge in LED design to create their own ultra-bright and ultra-durable light, dubbed the Min-T.

Continue reading "Ultra-bright and ultra-durable LED bicycle lights" »

December 9, 2008

Chipiplexing LEDs

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We've written about Charlieplexing LEDs before - see Charlieplexing - Cylon-eyes and Holoclocks - but here is a new one: Chipiplexing LEDs!

Charlieplexing is an electronics technique - apparently named after one Charlie Allen, an engineer at Maxim - which minimises the use of I/O pins on a microcontroller to drive a maximum number of LEDs. It dirves individual LEDs sequentially, whereas Chipiplexing - a term coined by the author of this Design Idea, from his own nickname - can drive a number of LEDs simultaneously.

With Charlieplexing, for example, using the same pin to alternate between driving digits (cathodes) and segments (anodes), Chipiplexing adds N cheap, bipolar transistors to the mix.

Author Guillermo Jaquenod writes:

Continue reading "Chipiplexing LEDs" »

January 6, 2009

LED Luminaries take a blogging bow

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Gadget Freak now has a sister blog - LED Luminaries!
LED-related posts are always popular on Gadget Freak - such as the year's most read posts, including such as the 500 LED 'extreme flashlight' and Pete decided to give his lamp a facelift - so do keep an eye on the new blog.

As its strapline says, "LED industry insiders, from Dialight, Carclo, Farnell and SKK Lighting share their insights on the issues shaping the development of LED technology in general and LED lighting in particular."

Posts already on the blog include:

Continue reading "LED Luminaries take a blogging bow" »

January 7, 2009

The Stribe - A DIY LED touch Interface



This one was flagged up for Gadget Freak by our Technology Editor, Steve Bush - a Do-Itself-Yourself LED Touch Interface, Hi-Fi style.

Continue reading "The Stribe - A DIY LED touch Interface" »

January 20, 2009

SpikePOV - Bicycle LED persistence of vision

spokepov 2.gifThanks to our Technology Editor, Steve Bush, for spotting this one - SpokePOV, or "persistence of vision for your bike". It's a way to have a bit of fun, driving LED lights to improve your bike's visibility.

According to the website, "Spoke POV is an easy-to-make electronic kit toy that turns your bicycle wheel into a customized display!"

"The project includes a free schematic design, open software for uploading and editing stored bitmap images, and a high-quality kit with all the parts necessary to build your own."

It promises, with one spoke, total persistence at 15mph. Two spokes, 10mph. Three spokes, 7mph. (Assuming a mountain bike wheel).

Details of the specification include:

Continue reading "SpikePOV - Bicycle LED persistence of vision" »

March 20, 2009

White light colour rendering trial circuit

White Light Colour Rendering Trial Circuit 1 small.jpgThanks to Geoff for sharing this circuit with us. He decribes the circuit as "a simple way of panning between led colours, amber and cyan, to give white light with control over how warm it looks".  Will temperature control overcome colour rendering objections, he asks?

He was spurred on by a recent LED Luuminaries post - Why can LED not yet rival halogen?

Check out the two diagrams:

Continue reading "White light colour rendering trial circuit" »

April 21, 2009

Is that my office phone ringing?

gadget freak phone indicator main.jpgIs that my phone ringing? By the flashing of light ye shall know...

Thanks again to our sister site Design News for this Gadget Freak, which involves a Remote Telephone Indicator. A relatively simple circuit, devised by Alan Vogel, addresses that perennial office question, arising as soon as you move away from your desk: Is that my phone ringing?

Well, if the indicator light is flashing, you will know. As long as it is visible from the coffee making facilities, water cooler or a colleague's desk...

The clever bit is that it doesn't involve re-wiring the phone. The device is stand alone, sensing the ringing light on a phone's fascia.

Continue reading "Is that my office phone ringing?" »

May 7, 2009

Build your own LED cube

led cube 1.jpgThis month's featured Gadget Freak is provided by an old favourite of the blog, Peter Griffiths. He shares all the details necessary to build your own 5 x 5 LED cube.

Construct your own programmed light display

Once again, the project is fully documented in terms of parts and the build process, and Peter provides a number of photos to help navigate construction.

The project also includes a ready to program HEX file with some demo cube animations and also the source code. The firmware implements a simple macro drawing processor command set, so if you've got some programming skills you can create your own animations for the cube, says Peter.

Although the project uses a PCB, the original prototype was constructed on a prototype pad board so if you're not able to make your own PCB it's still possible to make this project yourself.

Continue reading "Build your own LED cube" »

May 8, 2009

A DIY LED (SiC)

SiC pic 1.jpgThanks to our Technology Editor Steve Bush for flagging this one - Build a DIY LED - which continues the LED theme nicely, following our Build your own LED cube post.

It is a fascinating article by one Michael T. Lippert about making a light emitting diode from a pin and the mineral Moissanite.

He states that this is Silicon Carbide or Carborundum (compound of Silicon and Carbon - SiC) and that he used a less rare synthetic form of it:
Most of you will know this substance as the black "sand" splinters on sand paper. Due to its extreme hardness it is most often used in abrasive substances and tools. You could easily cut glass with it. I picked up four boxes with 1 cm big crystals for one Euro total on Ebay.

Continue reading "A DIY LED (SiC)" »

May 15, 2009

Cree Q5 LED Super Caplamp

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A recent Engineer in Wonderland post on the Electronic Weekly Electro-rambling blog mentioned developing an LED helmet for underground cave explorers.

Whereas 'Alice' backed away from this potentially life-critical project - imagine the potential consequences of failure in critical conditions - a reader emailed to flag their own successful builds. These were based a project described on Mine Explorer - see Miles's Homemade Cree Q5 LED Super Caplamp!

As the name suggests, it's based on the Cree Q5, which produces 230 lumens of light when consuming about 3.7 watts of power. As no headlamps were available based on the new emitter, Miles decided to build his own, and he says it wasn't particularly difficult or expensive to do, but there were impressive results.

Continue reading "Cree Q5 LED Super Caplamp" »

May 21, 2009

Peggy 2 LED array becomes animated video




Peggy 2, I love you...

Thanks to our technology Editor, Steve Bush, for flagging this one. It dovetails nicely with our recent Build your own LED Cube post, and involves the programming of a colour LED array. A Peggy 2 LED matrix display, to be precise.

There are 625 LEDs in total, with red, green, blue and white LEDs making some giant pixels, and the idea is to create something approximating video, via animation of the "RGB pixels". Check out the video.

Continue reading "Peggy 2 LED array becomes animated video " »

June 4, 2009

LED Bulbdial Clock shadows the time

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Wow! What a strange but clever idea: a "Bulbdial clock" - applying the principles of a sundial to (adjustable) electric light.

Back in March 2008, David Friedman published the idea on his blog Ironic Sans*.

He writes:


The Bulbdial Clock [pictured, below] has no hands - just one pole in the center of the clock, and three light sources of varying heights which revolve around the pole casting shadows. In the model illustrated above, the light sources are each attached to a ring which rotates around the pole. The innermost ring rotates once per minute, casting a "second hand" shadow. The middle ring rotates once per hour, and casts the "minute hand" shadow. And the outer ring rotates once every 12 hours, casting the "little hand" shadow.
Well, the excellent evilmadscientist.com website picked up this bulb and ran with it, as it were, constructing a working, LED-based bulbdial clock that builds on the original concept.

Continue reading "LED Bulbdial Clock shadows the time" »

July 6, 2009

LED Lightlane increases bicycle safety at night



Bicycles and LEDs are always popular topics for Gadget freak and this one is an excellent combination of the two - LEDs to create a virtual bike path, ie give a visual indication to other road users of the width needed for the bike.

Thanks to Geeky Gadgets for this one. It writes:
This excellent idea was originally a concept in a design competition which we covered back in January 2009 but due to the fantastic response from cyclists all over the world the inventors have decide to produce and market a working product.

Continue reading "LED Lightlane increases bicycle safety at night" »

September 7, 2009

In the (LED) light

bulbdial clock 1.jpgAhead of September's imminent competition post, here is a roundup of some LED related posts on Gadget Freak.

They range from a pot-holing cap lamp, and spoke-based bicycle displays, to full LED cube construction and the fantastic LED bulbdial clocks:

Continue reading "In the (LED) light" »

January 7, 2010

In the mood, with jukebox selections

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Another one for musical Gadget Freaks. Zach Glueckert and friends have designed a "moody" jukebox.

As well as operating like a normal Jukebox, where individual tracks are explicitly selected, the self-built device can also operate in "Mood Mode".

Apparently the gadget uses sensors to identify environmental factors such as temperature, light and sound. From this it determines which of its mood settings is most appropriate, and then selects corresponding music to play.

Continue reading "In the mood, with jukebox selections" »

February 9, 2010

Circuit Design Idea: Drive 12 LEDs with one I/O line

Drive 12 LEDs with one IO line.jpgFor those seeking circuit design inspiration, a new Design Idea has been uploaded to the site, on the topic of expanding the I/O of a pin-limited microcontroller.

The article begins:
The prototype display uses Kingbright's SC52-11EWA high-efficiency LEDs, which emit 2000 to 5600 µcd at a forward current of 10 mA. The driver is a 12-stage NXP 74HCT4040 binary counter or a 74HC4040 version for a lower power supply.

Continue reading "Circuit Design Idea: Drive 12 LEDs with one I/O line" »