I'm using a Raspberry Pi 3B.

What is the easiest way to make and break a single connection under program control - just like touching two wires together?

closed as unclear what you're asking by Milliways, joan, Dmitry Grigoryev, Ingo, Aurora0001 Jul 30 at 9:09

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    you can short anything to anything else to close a circuit ... the big question is what are you trying to do? – jsotola Jul 18 at 22:24
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    Just to be clear, I think foxrider's suggestion above is incorrect and could result in you cooking your Pi. Or it might work, but without further information you can't know. – Mark Smith Jul 19 at 20:54
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    That comment (now deleted) seemed to imply a GPIO set high could be connected directly to ground without frying the Pi, which is false. – goldilocks Jul 30 at 13:28

Buy a cheap relay from Amazon (like this one: Amazon GBP7 for five units) and use this to switch your signal. Don't try to connect your circuit directly to GPIO without a relay.

  • Hi Jonathan,description of your relay is 10+ years out of date. It mentions PIC, AVR, DSP, Arduino, but how come most popular Rpi is not mentioned? I know PIC and Arduino are MCUs. But are AVR and DSP MCU or SBC? I have the feeling that the Amazon UK guys do not speak English and do not know Raspberry Pi. - ARCELI 5PCS KY-019 5V One Channel Relay Module Board Shield For PIC AVR DSP ARM for arduino Relay by ICQUANZX ( amazon.co.uk/ARCELI-KY-019-Channel-Module-arduino/dp/B07BVXT1ZK/… ) – tlfong01 Jul 20 at 0:46
  • Sorry for the delay replying. The 5V relay shown works fine with the Pi - I have done this many times. – Jonathan Jul 30 at 10:41
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    Hi @Jonathan, No worries. I have been using the relay you are recommending for over a year, and so far so good: RE: RELAY MODULE KY-019 5V Postby tlfong01 » 2018-Jun-02 Sat 10:10 pm raspberrypi.org/forums/viewtopic.php?f=37&t=77158#p1323061, What I found surprising is that Amazon UK speaks broken English, and doesn't even mention that their KY019 relay is Rpi compatible, otherwise their sales should at least double by now. – tlfong01 Jul 31 at 2:50
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    Yes, Amazon is selling millions of things, so no time to pay attention to each of them. BTW, I found Hobby Electronics RALAY5VM description very good. (1) hobbytronics.co.uk/5v-relay-module?keyword=relay, (2) hobbytronics.co.uk/about-us. – tlfong01 Aug 10 at 8:53
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    My pleasure. BTW, though those York guys at Hobbyist Electronics don't speak Oxford or BBC English, their technical presentation is professional and at the same time hobbyist and newbie friendly. – tlfong01 Aug 17 at 1:05

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