Back to the future
Sometimes the best way to take a step forward is to take a step back in time. So Andrew Smith designed a fully-functional toy oscilloscope, made out of parts he found in his junk box, such as the EF91, EF80 and EF184 valves. Using a DC-DC converter to power the old (but still working) 7cm CRT he discovered in his loft, Andrew housed it in the same wooden box as the rest of the circuitry. The whole system runs from a single regulated 12.6V DC supply, which can be derived from a “wall-wart” PSU. Doc Brown would be proud.

Continue reading "Meet Andrew's blast from the past" »
This link explains how to build your own DigiThermo to measure time and temperature.

Continue reading "Build your own DigiThermo" »
An accurate PC thermometer you need all year round
Award-winning designer Alberto Ricci Bitti designed this simple microcontroller-free DS1621 PC thermometer that requires no calibration. It’s so cheap and simple because all you need is the sensor IC, a voltage regulator and a handful of diodes and resistors. It can be plugged into any free serial port and the temperature is shown on the Windows taskbar. Lucky for us, Alberto’s friends all asked for a PC thermometer of their very own, so he decided to release the build instructions into the wild. A cheap and simple PC thermometer? Now that’s hot. Or should we say cool?

Continue reading "Keep your PC cool this winter" »
Now he’s got the power to cut lightning down to size
People have always been fascinated by the fury of the heavens. Electronics prodigy Richard Hodgkinson created a lightning distance timer so he would no longer have to manually calculate the approach or retreat of a thunderstorm. He recycled a 70 KHz crystal from an old device for the oscillator. “Let there be light,” he declared as two HP 45MGC670 surface mount LEDs were attached to allow him to see measurements in the dark. And his project wouldn’t be complete without two 1.5V AA cells which are the heart of his timer. Now his creation is alive, all he needs is a wicked thunderstorm.

Continue reading "Richard had a flash of inspiration" »
Thanks to
Design News for this Gadget Freak, in which NASA engineer Bob Wilson takes the office temperature.
He devised a technological solution for a bureaucratic problem: convince building maintenance that his office was frigid in the morning.
By the time anyone responded to a call, the heat was on. So he programmed a TI MSP430-F2013 microcontroller to record the temperature continuously over several days.
The size of a quarter dollar and powered by a 3V lithium cell, it records converted, filtered, RL-encoded data from its built-in temperature transducer into Flash memory, to be read back later via a USB interface. The maintenance department was convinced.
Continue reading "Thermal management for a frosty office atmosphere" »

Take a look at another
Circuit Design Idea we have uploaded to the site.
It covers the use of a microcontroller in a nonstandard task, not just detecting a pulse but detecting it as part of a wider dozen tests and measurements.
The Design Idea begins:
While recently designing an automatic test station employing a microcontroller, I faced a nonstandard task: Detect the presence or the absence of output pulses in the DUT (device under test). You might think this task is easy to accomplish by connecting an LED to the DUT output. The blinking LED provides evidence of the pulse's presence. That approach would work if that test were the only one you needed to perform.
Continue reading "Circuit Design Idea - Microcontroller detects pulses" »

Check out another newly-uploaded
Design Idea designed to give circuit building inspiration.
It involves a sample-and-hold amplifier that tracks and holds the difference of two input signals.
The Design Idea begins:
You can fulfil a requirement for sampling the difference of two signals in two classic ways. You can subtract the two input signals with an instrumentation amplifier whose output connects to an input of a classic sample-and-hold amplifier.
Continue reading "Circuit Design Idea - Amplifier holds the difference of two inputs" »

Check out another newly-uploaded Design Idea designed to give circuit building inspiration.
It involves simple 'toggle' circuits to demonstrate the low gate leakage of modern power MOSFETs.
The Design Idea begins:
The novelty circuit in Figure 1 illustrates the extremely low gate-leakage current typical of modern power MOSFETs. You can find parts that, in a moderately dry environment, will hold their state for days at a time. In operation, if MOSFET Q1 is off, the load - perhaps a lamp or a buzzer - pulls Q1's drain to nearly the 12V-dc power-supply voltage. R2 charges C1 to practically the same voltage.
Continue reading "Circuit Design Idea - Illustrating low power MOSFET leakage" »

Here's a Circuit Design Idea fresh to the site -
Locked-sync sine generator covers three decades with low distortion (click on the circuit diagram to expand it).
It covers a sine-wave generator that can synchronise a sine-wave output through three decades of frequency and maintain low THD and constant amplitude.
The Design Idea begins:
Analogue applications, such as testing, calibration, and general system operation, often require a sine waveform of accurate amplitude and frequency, with low THD (total harmonic distortion). Some applications demand that the generator of such waveforms have the ability to accurately synchronize the output with an external timing signal.
Continue reading "Circuit Design Idea - Locked-sync sine generator" »
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