WARNING: Turns out this violates a lot of usb safety regulations, and pumps 5v into your usb port. While this is not harmful on a lost of computers, this MAY FRY YOUR PC’s usb port. I will post an updated design later this week that is actually safe!
Hey all, this is my first post on this blog, so I’d like to say hello! I’m Ian M, a high school student who likes breaking(/fixing(/breaking again)) electronic stuff. I was just sitting around, and I wanted to see how cheap I could make a usb avr isp programmer. I based the design off of http://www.simpleavr.com/avr/vusbtiny, which is based off of the original UsbTinyIsp. For the firmware, I just took their firmware and re-compiled it. The source is available at http://www.simpleavr.com/avr/vusbtiny/vusbtiny.tgz?attredirects=0. Their post uses 3 resistors, 2 diodes, 1 capacitor, and an MCU. I thought I could do better. Turns out you don’t need two of the resistors, or the diode. My schematics are released into the public domain, and the original code stays under its original licence (which I don’t exactly know what it is, but I bet it’s in the readme).