Project files are hosted on GutHub.com.

Micro Relay Board

I designed this to use a small signal relay () with a small package to use in many of my projects that need a relay without a log of space available. The silkscreen for the relay contacts are reversed and haven t had the motivation to update it as I am probably going to be the only person using it, but just in case I wanted any else to be aware of that. The board uses a sot-23 diode as a flyback diode across the relay coil, and it is input signal is active high which drives a transistor to pull the relay to ground. So the signal input does not directly drive the relay because that might pull more current than a microcontroller can provide from a single pin. The two pin header is there to easily check that the relay functions them out. Design is about as small as I could make so the fab costs are pretty low.

Dual Row Header Edge Conntector

A Buffered USBtiny AVR Programmer

This is essentially just a clone of the Adafruit buffered USBTiny programmer. Uses an ATTiny2313 AVR chip controlling the programming. I used two thru-hole zeners on the USB connection because I had those specific zener diodes on hand, otherwise I would have used surface mount components. Same is true for most of the through-hole components.