Collect And Analyze ECG Data

August 22, 2009 by Zach Banks 14 Comments

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Although we’ve covered DIY ECGs before, [Scott Harden] sent in his version that gives an in-depth explanation of what to do with the collected data. He built a basic battery-powered op-amp-based ECG for under $1. The circuit just amplifies the signal from the chest leads and feeds it into a computer via the microphone port. He then used GoldWave to record, filter, and save the signal. From there, he used python to analyze the heartbeat and calculate his heart rate and further manipulate the data. His previous blog posts go into more detail on how the python code works and why he chose software over hardware filters.

Teardown Of The Barista

August 18, 2009 by Steve Watkins 15 Comments

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iFixit has done a tear down on the symbolic do-it-yourself Espresso machine, the Starbucks Barista. Believe it or not, there is not a single circuit board in the works. There doesn’t seem to be much to the Barista; A few switches, some solenoids, a heater, and one way spring valve among other things. The assembly of the device is very simple. It is noted that in a pinch it may be torn down with a pair of pliers and washer; in place of a flat head screw driver. We have pondered the possibilities of this machine numerous times, while enjoying a cup of cappuccino. Though most conversations end at the bottom of the cup, many survive such as this Silvia PID looped expresso machine. The very name “Mecha turbo crazy coffee roaster” seems to encapsulate the effects of caffeine quite adequately.

Solid State Tesla Coil

August 14, 2009 by Steve Watkins 9 Comments

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While researching solid state Tesla coils we stumbled across this old project. As you have probably guessed from the pictures, this coil is meant to actually play music. Knowing how to add eye catching flare, the coiler uses a Plexiglas frame turned light pipe; only to be complimented by an audio amplifier complete with graphic equalizer. There is a video of the coil in action on YouTube. We have covered singing tesla coils in the past. Other twists on the classics include the tesla coil guitar amp and a hand held plasm gun.

Serial Hacking With An ATtiny2313

August 6, 2009 by Steve Watkins 19 Comments

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[Sprite_tm] automated a portion of serial hacking by sniffing out the baud rate using an ATtiny2313 and FT232 breakout board. The firmware assumes 8 data bits, no parity, and 1 stop bit (8N1). This is pretty much defacto among serial ports so it should work well, though some devices do use different settings. The auto detection routine can sniff rates as low as 110 baud and supports non standard rates. Released under GPLv3, the software is also supplied in hex format. [Sprite_tm] has provided great project in past such as Working with VFDs, Controllable bristlebot, and AVR boost converter. Additional information regarding serial hacking after the break.

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Review: The Manga Guide To Electricity

August 5, 2009 by Gerrit Coetzee 377 Comments

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“The Manga Guide to Electricity”, part of “The Manga Guide” series by No Starch Press, is a novel approach to the old problem of getting over the initial mental block when trying to learn electronics.

We decided to compare this book to another introductory text: “Getting Started in Electronics” by [Forrest M. Mims]. [Mims]’ book is a handwritten masterpiece of electronic literature. The writing style is friendly and concise, the examples are simple, and the drawings are excellent. It also makes sure to keep the learning process as application based as possible. Unlike other books, it doesn’t bog the reader down with math and theory that is only useful to advanced students. Since its original printing in 1983, [Mims]’ has become the de facto standard for beginner electronic literature. Continue reading “Review: The Manga Guide To Electricity” →

Sticky Light

August 4, 2009 by Zach Banks 25 Comments

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With the availability of webcams and projectors, multitouch and interactive demos have become increasingly popular because they’re so easy. Students at the University of Tokyo took a new approach that uses lasers instead. They created Sticky Light, which uses mirrors, a laser, and a single photodetector. Unlike camera-tracking setups, this system requires no visual processing. The laser moves around and bumps into dark objects, sticking to them. It can follow drawings on the table or objects in space, such as shirt designs. They also created a few basic games and a demo that makes sounds based on the movement of the spots. Video of the project after the break.

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BPSK On 433 MHz European ISM Band

August 3, 2009 by Steve Watkins 10 Comments

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[WaveRider] is using a type of phase shift keying called BPSK to transmit digital sound and video for remote telemetry. Though a higher signal to noise ratio (SNR) is generally sought after with communications, legal limitations are imposed on total radiated power. To balance the two headed beast, he opted out on frequency shift keying due to binary shift keying’s ability to work with lower SNR. This adds the difficulty of properly reconstructing the digital signal at the receiver. A PLL based carrier regeneration circuit is used to reconstruct the signal. Using the Rabit2000 processor as the host controller on both transmitter and receiver, 96KB/Sec serial data is obtained. On the other side of the spectrum is the Homemade regenerative tube radio.