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…

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[Bill2009] has made some nice progress on a control panel for his motorcycle over at the arduino.cc forums.  It can show speed, tachometer readings for the wheel and engine, as well as indicate the current gear. He reads the square wave coming off of his tachometer input and pulses from a reed switch mounted on the wheel to calculate all this. To top it all off he can monitor the data via a Bluetooth module attached to the board, which is much better than trying to balance a laptop on your knees while cruising down the highway.  He is…

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