AVRISP MKII Power Mod

I use the Atmel AVRISP MKII to program many of my ATTiny projects.  At approx. $35, it cheap and easy to use.  However, one thing that annoys me is that it requires the target board to provide a source of power or it won't program the chip.  So, I set out to modify my unit to add a switch that lets me draw 5 volt power from the USB connection.  Here's a photo of the AVRISP MKII with it's new power switch installed:

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The first step was to remove the cover by gently prying apart the 4 snap lock tabs on the underside of the unit.  Next, remove the circuit board by prying open the two tabs that hold it in place.  Then, solder a short, 4 inch length of wire wrap wire (or similar) to pin 2 of the header that connects to the ICSP programming cable.  Here's a photo that shows this step:

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Then, drill a small hole in the side of the case to accommodate a SPST switch, such as Radio Shack Model: 275-624.  Next, using the following photo as a guide, use a short length of wire wrap wire to connect pin 1 of the USB connector to the switch.  Then, connect the other wire from pin 2 of the ICSP header to the other switch connection.

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That's it!  Once you reassemble the case, the programmer is ready to go.  If you've Radio Shack Switch and oriented it the same way as in the photo above, moving the toggle bat toward the ICSP ribbon cable end should engage power and moving it to the opposite position should remove power and leave the unit to function as it was originally designed.  Note; when selecting to use power, the LED on the top of the case should witch to GREEN when you engage the power switch, just as it does when you connect power to the target board.

Caution - you'll need to make sure the target system does not supply power when you use this new feature and that the target board you're trying to peer does not consume more than the USB cable can supply (assume no more than 200-300 mA to be safe.)