I would like to share pictures of my cheap and simple USB AVR ISP programmer. It is based on only one IC, the Atmel AVR-USB MCU AT90USB162.
It works perfectly, I can even repair and hack it, not as the official AVRISPMK2 from Atmel :-( Luckily Atmel did share the application note "AVR911: AVR Open Source Programmer" on which this Free/Open hardware/software USB AVR ISP programmer is based.
Hardware schematic files and PCB files are Free to use, and they were designed with KiCAD (Free software). Also, the firmware used is the MyUSB Library which is Free Software.
There is PCBs selling on Ebay, or all the board assembled. If you decide to buy all the components and build it, there is no need to use any programmer to program the AT90USB162 as it comes with an USB bootloader from Atmel factory ;-) - it's very simple to update firmware and hack this programmer :-)
Get all the information here:
After getting 6 units of AVRISPMK2 burned at my working company, I emailed Atmel and asked for schematic and firmware of it, so I could repair them. The answer were:
The schematics and source code for the AVRISP mkII are considered internal information, I am sorry that I cannot send them to you. If the troubleshootings table and the hardware block information from the AVR32studio help menu is not enough for your AVRISP mkII, please contact to our local distributors at: Atmel Contact Page.
AVR General Support
Atmel Technical Support Team