CheapStat: An Open-source Potentiostat

September 14, 2011 by Mike Szczys 12 Comments

A commercial potentiostat can cost several thousand dollars, but the CheapStat is an open source project that makes it possible to build your own at a tiny fraction of that cost. It is possible to build one for less than $80, breaking down the cost barrier faced by many labs that would like to have this test hardware.

A potentiostat is used to measure electrochemical properties. To give you a few examples of what it can do, the hardware can measure arsenic levels in water, Vitamin C concentration in orange juice, Acetaminophen concentrations in over-the-counter medications, and a bunch of other less easily explained tests having to do with chemical compounds and DNA.

The device makes use of an Atmel XMEGA microcontroller and connects to a computer via USB. A Java program grabs that data from the hardware displaying test results on your choice of computer platforms. If you’re looking for all the gory details you won’t be disappointed by their journal paper.

Video – Eagle CAD’s CAM Processor

September 14, 2011 by Jack Buffington 2 Comments

Here is the next installment in our series of Eagle CAD videos. In this video we skip ahead a bit and show off the CAM processor that you use to create the files necessary to have your circuit boards be manufactured. After watching this video, you will know how create a new CAM program, load a circuit board into the CAM processor, tell it where to save your files, and actually use it to create the files.

We’re skipping ahead today because of a screw up on our part. We meant to show the layout portion of the program today but edited the wrong video… We’ll show layout next week. After that, we will show the completed circuit board and solder the parts onto it.

If you are itching for some Eagle CAD layout info, you may be interested in some supplementary videos that we have uploaded to our Youtube channel. In those videos, we show how to use the most important features in the layout portion of the Eagle CAD.

Have you missed the previous videos? Here are some links to them:

Schematic and the beginning of a custom part: [click here]
More custom part stuff: [click here]

Video is after the break:
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Making Better CNC Halftone Pictures

September 14, 2011 by Brian Benchoff 29 Comments

[Jason] was messing around with CNC machines and came up with his own halftone CNC picture that might be an improvement over previous attempts we’ve seen.

[Jason] was inspired by this Hack a Day post that converted a image halftone like the default Photoshop plugin or the rasterbator. The results were very nice, but once a user on the JoesCNC forum asked how he could make these ‘Mirage’ CNC picture panels, [Jason] knew what he had to do.

He immediately recognized the algorithm that generated the Mirage panels as based on the Gray-Scott reaction-diffusion algorithm. With this algorithm, dark areas look a little like fingerprints, meaning the toolhead of the CNC router can cut on the X and Y axes instead of a simple hole pattern with a traditional halftone. After a little bit of coding, [Jason] had an app that converted an image to a reaction-diffusion halftone which can then be converted to vectors and sent to a router.

It’s a very neat build and we imagine that [Jason]’s pictures would cost a bit less than the commercial panels. Check out the video after the break to see the fabrication process.

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Quadcopter Stabilization System Using Wii Motion Plus

September 14, 2011 by Mike Szczys 15 Comments

If you’re contemplating a quadcopter build here’s a way to add stabilization hardware without breaking the bank. The BaronPilot project uses an Arduino and a Wii Motion Plus module to ensure an even keel for your flying projects. The hardware inside of the Motion Plus includes two gyroscopes, which the BaronPilot monitors for changes in your flying rig’s orientation. The project serves as a co-pilot by differentiating between movements caused by the remote control, and changes due to wind or other outside factors (like hitting the quadcopter with a stick as seen in the video after the break). It should all translate to less chance of crashing due to operator error.

You can pick up a Motion Plus for less than twenty dollars, a deal when compared to the IMU boards that we usually see in quadcopter builds which usually run more than twice that amount. It’s an I2C device which makes it easy to hook up to just about anything. This project has native support for Teensy, Arduino Nano, and Arduino clones using an ATmega328 chip. But the portability of the Arduino platform should make it easy to tweak the code for use with just about any microprocessor.

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Keeping Simple Children’s Toys Interesting With Small Modifications

September 14, 2011 by Mike Nathan 20 Comments

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[Jaroslav] was racing slot cars with his son not too long ago, but like many of us discovered in our youth, driving cars around a small oval track can get dull after awhile. Rather than buy more track sections, he decided to fiddle with their cars a bit to make racing them a little more exciting.

After removing the top of his slot car, [Jaroslav] found that it cruised around corners with ease, giving him a distinct advantage over his son. He did the same with his son’s car to level the playing field, then he decided to add a few extra LEDs to make driving around the small track more lively.

Now, this obviously isn’t the most advanced of modifications, but it is a great example of extending the useful life of a toy by using cheap, easy to access components. We think that it would be reasonable to add even more features to the cars/track such as speed-dependent lighting or lap counters without changing the car dynamics all that much.

Any thoughts or suggestions to help [Jaroslav] soup up his kid’s race track even more? Share them with us in the comments.

A Laser Cutter Challenge

September 14, 2011 by Brian Benchoff 14 Comments

When the Louisville hackerspace LVL1 was discussing the purchase of a new laser cutter, a member said, “I could build one before you get around to buying one.” The gauntlet was thrown down, a challenge was set, and the race was on to build a tiny laser cutter before the hackerspace took delivery of their new laser cutter.

The mechanical aspect of the build is fairly simple. The X axis is simply a stepper motor, threaded rod and laser module mounted on a carriage. This carriage moves along the Y axis with the help of two stepper motors for either side. Everything was mounted on more perfboard than reason would suggest.

For the electronics of the project, three motor drivers were made with a few logic chips and the laser firing relay was stolen from test equipment developed for LVL1’s trans-Atlantic balloon build. Motor and laser control was handled by an Arduino to keep the build simple because the contest was over after the first laser was finished cutting a square.

LVL1 is now working on a second version of the winner of the laser cutter challenge. They’re planning on a touchscreen interface that will cut a plastic blank about the size of a credit card. We can’t wait to see the results of that build.

ATtiny Hacks: Look Ma, No Batteries!

September 14, 2011 by Mike Szczys 30 Comments

ATtiny Hacks Theme Banner

[Gadre] built his own ATtiny project without using any batteries. It’s an electronic Dice (or die if you’re being critical) which uses induction to charge a storage capacitor to act as the power source. The voltage generator is made from a tube of Perspex which houses a set of rare-earth magnets. At the enter of the tube [Gadre] machined a channel wich accepts about 1500 windings of 30 AWG magnet wire. When someone shakes the tube back and forth the magnet passes the wire, inducing a current. The product is stored in a 4700 uF capacitor, which feeds a boost converter to power the rest of the circuit.

The ATtiny13V that controls the circuit is running its internal RC oscillator at 128 kHz, the lowest setting possible in order to minimize power consumption. After a good shake the user can press a button to roll the die, which is then displayed for several seconds on a group of seven LEDs. See for yourself in the video after the break.

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