Battery Desulfator

July 5, 2009 by Eliot 30 Comments

mini-d

Hack a Day favorite [Mikey Sklar] is back with a new project. Mini-D is a battery desulfator. If a 12V lead-acid battery sits with a voltage below 12.3V, sulfur crystals will begin to form on the lead plates. This crystal growth increases the internal resistance and eventually makes the battery unusable. A battery desulfator sends high frequency pulses through the battery to create a resonance that will break up the crystals. On a 60lb automotive battery, it will take approximately three weeks to completely desulfate. You can find schematics plus a dozen lines of code for the ATmega169 on his site. Embedded below is a video where he explains the device and other techniques like load testing.

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Capacitive Discharge Spot Welder Update

July 5, 2009 by Eliot 22 Comments

welder

It seems one of our commenters took great umbrage with [PodeCoet] not documenting his capacitive discharge cutting properly. [PodeCoet] had been waiting till he got the full spot welder working before publishing, but he’s expedited the work after all our whining. Check out his full writeup of the device in its current state. It uses a 1Farad audio cap for storage. A dsPIC monitors all of the voltage sources and regulates charging. A nice touch is the tactile switch on the electrode.

Capacitive Discharge Cutting

July 4, 2009 by Steve Watkins 25 Comments

capacitive discharge cutting

Capacitive discharge cutting provides more control than linear transformer versions. A very large capacitor is charged to a precise voltage and then discharged through the material to produce a controlled cut. The same device can also be used for spot and tab welding. A video of copper roof flashing being cut is embedded below. An example of a linear transformer can be found in our our How-to: build your own spot welder.

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How-to: Bus Pirate Probe Cable

July 2, 2009 by Ian 24 Comments

cover

Update, Saturday July 4th, 2009: All preorders are closed.

A probe cable makes it easy to connect the Bus Pirate to a circuit and get hacking. Good test clips make quick connections on cramped PCBs without causing short circuits. We made two cables for the Bus Pirate v2, keep reading for an overview of our designs and list of part suppliers.

Friday, July 3, 2009 is the last day to pre-order a Bus Pirate. There’s only two days left to get your own Bus Pirate, fully assembled and shipped worldwide, for only $30.

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T.G.I.M.B.O.E.J. Turns One

July 2, 2009 by Caleb Kraft 14 Comments

tgimboej

The Great Internet Migratory Box of Electronics Junk, or T.G.I.M.B.O.E.J. has turned one. In the last year, they’ve learned a lot of things. They learned that lots of people are willing to contribute. Hundreds have signed up on the site to participate. Theyve also learned that laziness is the key road block on this project. The boxes that have stalled generally sitcollecting dust, simply because someone hasn’t bothered to ship it off. If you’re curious what kinds of stuff ends up in one of these, check our initial post. There aren’t any guarantees though, it all depends on what people toss in.

Poor Man’s Thermographic Camera

July 1, 2009 by Steve Watkins 24 Comments

thermographic camera

Using an IR thermometer, there are two ways to go about building a thermographic camera. The first uses a pan and tilt head. Scan lines are emulated, as a computer controls panning from left to right, taking a temperature sample from each step. Vertical resolution is accomplished by tilting. Another method uses a web cam attached to the thermometer. The thermometer’s laser pointer is captured with temperature annotations, as the computer records the field of view. We think the best outcome can be found with a combination of both methods. The video embedded below demonstrates the results. This would be a good addition to the Autonomous paintball sentry.

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Mixed Voltage Interfacing With The Bus Pirate

July 1, 2009 by Ian 7 Comments

oc.470.iii

Most of the parts we use operate at 3.3volts, but we still run into a lot of old 5volt stuff, and an occasional 2.5volt or 1.8volt part. This post explains how to use the Bus Pirate’s open collector pin mode to interface with parts at different voltages.

We’ve got more details and some example scenarios below the break. Yup, this is another Bus Pirate post. It’ll all be over soon though, because there’s a few days left to get your own Bus Pirate for $30, fully assembled and shipped worldwide.

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