pisupplyswitch-1Turning a Raspberry pi into a internet radio player is fun, but safely powering down requires (access to) a computer. The people of pi-supply.com launched a successful kickstarter project and now have a pretty device available to switch a Raspberry Pi on and off. Where the off signal triggers a halt command on the Raspberry Pi so it shuts down properly. All of it is open source so buy a small one of pi-supply.com or build a bigger one yourself and read on.

The schematic is shared and I ported it to Cadsoft Eagle for convenience. Instead of having two switches on the board I decided to have two pinheaders there only. I recon that in practice you want the on and of switches not per se near the power cables and I might build it all into a small case and then I definitely don’t need the switches on the board. The third switch, the hard off, I don’t need as it’s basically the same as unplugging the power cable.

pisupplyswitch-5 The double usb connector was salvaged from an old pc motherboard, the 5volt relay was bought on ebay and the rest I had available. I chose the dual usb connector as I need to power a usb speaker set, and this way I can switch those on and off as well without having to draw power from the Raspberry Pi.

Three connectors can been seen. Two to accommodate the on and the off switches (should be momentary switches). The third one is for the two wires that goes to the Raspberry Pi.

If you are going to build this as well please double check the relay you have to make sure it fits. I had to modify and existing part in the eagle library order to make the SONGLE Power Relay SRD-5VDC-SL-C fit.

The relay will set you back around a euro on eBay. The resistors, diodes and transistors are cheap ones and when buying them in pairs of ten they come down to 1 to 3 cents each. The connectors are a bit more and the usb in and usb out connectors are 1 to 3 dollar depending on how you want/need it. As said the double usb connector is a quite common part on pc mainboards, same goes for the connectors used for the wiring toward the buttons and the Raspberry Pi. If you’re able to etch or mill your own board this handy board van be yours for less then 5 euro.

Download Eagle schematic and board here. Note: they are not mine but from pi-supply.com. I left out the third button, and instead of actual buttons on the board I use pinheaders.

pisupplyswitch-2 pisupplyswitch-3 pisupplyswitch-4

 

 

 

 

 

 

 

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