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Microtouch!

====== Microcontroller ======

The brains of the Microtouch board is an [[http://www.ladyada.net/wiki/partfinder/microcontroller#usb_series|Atmega32u4]] in TQFP package. The nice thing about this chip is the built-in USB support and lots of pins. 

====== Lithium Polymer charger ======

The board has a built in single-cell 3.7v LiPoly charger ([[http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en527982|MCP73811]]). The LiPoly should be connected to the [[http://www.ladyada.net/wiki/partfinder/jst|2-pin 2.0mm JST-PH]] - verify polarity before connecting! The charger chip is very simple but will properly charge the lipoly. The charge rate is set to be 450mA peak, so do not plug it into a non-powered hub. It should work fine with any computer. Unfortunately there is no notification when the battery is charging (say an LED). 

====== 3.3V power supply ======

The output of the lithium polymer battery (or USB passthru) connects to a LP2985 3.3v LDO. This regulator is fairly good quality and will give about 1% precision output and up to 150mA
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