For switching of my radioberry On or Off switch with a single push button I was searching for a compact and simple design. I found the design of Kevin Darrah and designed a small PCB.
Why this fancy switch.... I like to use one button for On and Off for safe shutdown to avoid damage to my running kernel or data on the SD card.
The power mosfet can switch high currents however my home made PCB can go to about 8 amps this is limited by the connectors and copper tracks.
We use two gpio pins from the Raspberry one for switching the power Off after shutdown and one pin to start the shutdown sequence shutdown -h now.
The software is a Python script instead of using processing.io so as Kevin mentioned I used a python script for avoiding install extra software and create extra difficulties for Raspberry Pi users.
The install procedure is straight forward and needs no programming skills at all, the Python script is only 266 bytes.
Designed with Sprint
Single sided PCB, SMD sizes 0805 and SOT23, connectors with 3.81 mm pitch
Made with CNC machine, spindle at 10000RPM, feed speed at 180mm/min, milling bit 0.1 mm and 30 degrees, depth at 0.055mm leveling needed.
Tiny components and a big power mosfet, test version
Connections to Raspberry Pi and supply, test version
Perhaps a bit over the top but the PCB's are gold plated for easy soldering, price single PCB 9 euro including shipping worldwide.
Build and tested
The switch can handle about 8 amp.