Posted January 29, 2015 by Chris

"If you open a common optical mouse you will most likely find two chips inside — one being a general purpose micro-controller and the other an optical mouse senor. The sensor captures images of the surface below the mouse at high frame rate. It uses captured images to calculate the displacement the mouse is moved over time. Incidentally, it is also able to provide the raw image data. "

Posted January 28, 2015 by Chris

"Behold, the $75 DIY sous vide heating immersion circulator! By scrapping together parts that are readily available on eBay and Amazon, I was able to build a self-contained device that heats and circulates water while maintaining a temperature accurate to 0.1 degree Celsius."

Posted January 27, 2015 by Chris

"The theory behind a pulse oximeter is based around a simple principle: Shine red light and an infrared light through a blood-rich part of the body and measure the difference in absorbed light with a photo sensor. Hemoglobin absorbs red and infrared light differently depending on the oxygen saturation level. Based on this, it is possible to calculate the ratio of oxygenated vs. de-oxygenated hemoglobin."

Posted January 26, 2015 by Chris

"These things have become rather useful around the lab! In addition to the original key-switch operation, they’ve been put to use running optical shutters for pump lasers, turning deposition shields inside vacuum chambers, etc. Basically, any time we have a mechanical device we want to be in one of two positions, we use a servo and this board."

Posted January 25, 2015 by Chris

"I wanted to play around with the idea of composing color by utilizing the color-combining RGB LEDs. Using 3 different variable resistors I could adjust the levels of Red, Green, and Blue color elements separately. I was exploring the idea of actively ‘composing’ color for use in software like Photoshop, Illustrator, or some other art program. This glove is a self-contained first-step towards this kind of color control."

Posted January 24, 2015 by Chris

"Small tutorial on Computer ATX Power Supplies. How to use them, how to connect them in series, in parallel. What is 12V rails? Is it possible to connect 12V rails together? ATX connector wiring explained."

Posted January 23, 2015 by Chris

"I wanted it to be cheap to build with easy-to-find parts and very reliable as my wife does not appreciate cold showers: I decided to use a netduino-mini micro-controller, an AdaFruit DS1307 real-time clock and a servo to adjust the temperature of the water heater."

Posted January 22, 2015 by Chris

"I did this project to make myself a portable power supply I could bring around to test certain broken equipment which requires fixing. It is handy to be able to bring around a variable power supply such as this than to look for a suitable battery to power it up."

Posted January 21, 2015 by Chris

"The receiver circuit completes the modem’s hardware design. It is simply a two-stage amplifier that gives a total gain of about 2000, in series with a band-pass filter….The goal is for the receiver to output a signal that is around -10 V when idle and peaks at -5 V when it receives a signal. These voltages correspond respectively to logic low and high on the microcontroller."

Posted January 20, 2015 by Chris

"Today’s post is something I’ve prepared for a long time. Hardware-wise it’s a simple thing – ATtiny45 emulating a PS/2 device, sending a key press when three knocks are detected in the attached piezoelectric sensor."