Build Your Own Relay-Triggered Power Cord

I’m a big fan of the PowerSwitch Tail. It’s an awesome power cord equipped with a relay board that enables a relative neophyte maker (say, can run the Blink sketch in Arduino) to safely control high-voltage electrical sources. It’s great because it’s pretty much foolproof and as safe as any extension cord.

Ryan Edwards of Sparky’s Widgets shot this YouTube video showing how to build a DIY version of the PowerSwitch Tail that can switch up to 120VAC/12A.

Ryan reports that the total cost is under $20, which doesn’t compete much against the $27 PowerSwitch Tail (available at the the Maker Shed) but it’s always cooler to make one yourself!

12 thoughts on “Build Your Own Relay-Triggered Power Cord

  1. Having used the PowerSwitch Tail, I’ll note that the cords are very rarely a good length.

    If you’re making your own, make it with a IEC C13 on one side, and an IEC C14 on the other. That is, the standard computer in-and-out plugs and receptacles. Or at least the US standard NEMA 5-15 plugs and sockets. (Or local equivalents).

    Quite a few bins of “antique electronics”, and a significant slice of that is just the heavy duty power cords. Make it without a cord, make it easier to store.

  2. There’s a safety concern with the drilling – I suggest drilling with the plastic on a stable surface so you don’t drill into your fingers :-)

    Otherwise, a useful video with an alternative place to get these relays. I do know of a source of a different relay to do the same job, but when I inquired into it, it was a two-month wait.

    1. You are right about the drilling, I am a bit cavalier which such things, but its really a good idea to secure the object to be drilled without using ones fingers :) Also those relays are a bear to get ahold of I have since had to switch to RZSchracks and order them well in advance. This relay form factor really makes the most sense but is losing out in terms of popularity it seems.

Comments are closed.


My interests include writing, electronics, RPGs, scifi, hackers & hackerspaces, 3D printing, building sets & toys. @johnbaichtal

View more articles by John Baichtal