Category Archives: Electronics

Household thermal imaging

Posted on December 16, 2015 by gregorykimball

I am now the proud owner of a Seek Thermal infrared camera! Let’s play a game: it’s called “guess the subject of this photo”!

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Computer upgrade

Posted on December 11, 2015 by gregorykimball

Merry Christmas to me! It’s time for a motherboard upgrade. Here are the components I selected:

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USB toggle switch extension

Posted on October 19, 2015 by gregorykimball

Last week I found myself in need of a USB toggle switch. Such a device would allow me to toggle the power on a USB device without having to unplug it. It is true – I suffer from a disorder that requires me to construct a USB switch rather than simply unplug my devices.

This simple device uses a USB extension cord and a slide switch connected to the +5V power line (the red wire). If you happen to have a device [such as an external video card] that requires to be reset every few days, simply toggle the switch when a reset is needed.

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Upgrade halogen->LED

Posted on June 17, 2015 by gregorykimball

We have two 300W halogen flood lamps in the house, but I decided it was time for an LED upgrade. I selected the Cree 18W (90W equivalent) flood lamp as the replacement. I wanted to keep the 6ft tall lamp stand and dimmer, but remove the halogen housing, thermal runaway circuit and reflectors.

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$50 electronics test bench

Posted on March 18, 2015 by gregorykimball

I’ve been having a hard time finding oscilloscopes and adjustable power supplies in the “hobbyist” price range, but I think I have cobbled together a solution.

A few key components:

Power supply from old PC
- Make sure to short the correct pins to trick the power supply into turning on. This is usually green to black.
- yellow-black is 12 V
- red-black is 5 V
- orange-black is 3.3 V
- If you want other voltages, well.. time to built a buck-boost circuit!
Gabotronics Xprotolab mini oscilloscope
- 2MHz sampling
- 8 bits resolution
- $50 (the best part)

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Pitch to Color

Posted on March 16, 2014 by gregorykimball

Here is the color wheel used by my electronic instrument, Abella. When the music box is playing “C”, the pitch display appears yellow. Middle “C” is set at 262 Hz, high “C” at 523, and low “C” at 131 Hz, and each is displayed yellow. The remaining notes occupy a RGB-CMY color space.

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Shift registers and Voltage display

Posted on March 2, 2014 by gregorykimball

I’ve been having great fun with the Arduino Uno microcontroller board. Here I’ve got the Arduino using a shift register to light up a 7-segment display output.

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Introducing Abella

Posted on June 26, 2013 by gregorykimball

Sound and light!

http://www.youtube.com/watch?v=ccJRsY-8vOs

Here is some footage from early hardware development of “Abella,” my Arduino-powered electronic instrument. Yes, it is in a shoebox, and yes, the control knobs are popped through the cardboard. Continue reading →

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USB car charger, 2A

Posted on June 24, 2013 by gregorykimball

The more I’ve learned about switch-mode power supplies, the more amazing it seems to me. So a voltage source across a wide range of values can be converted into another voltage, just by pulsing current though an inductor. Of course, switch-mode power supplies are even easier to set up with ICs like this one:

IC REG BUCK BOOST, 296-17764-5-ND

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