DIY Clapper is 1980s Style With Raspberry Pi Twist

Home automation isn’t all that new. It is just more evolved. Many years ago, a TV product appeared called the Clapper. If you haven’t heard of it, it was basically a sound-operated AC switch. You plug, say, a lamp into the device and the clapper into the wall and you can then turn the lamp on or off by clapping. If you somehow missed these — and you can still get them, apparently — have a look at the 1984 commercial in the video below. [Ash] decided to forego ordering one on Amazon and instead built her own using a Raspberry Pi.

[Ash’s] prototype uses an LED and could — in theory — drive anything. If you wanted to make a real Clapper replacement you’d need a relay or some other kind of AC switch suitable for the load. The actual clap detection software is from [nikhiljohn10] and simply waits for two loud noises. No fancy machine learning to differentiate between a clap and a cat knocking over a vase. Just a threshold and some timing.

Of course, the Pi can’t hear anything unless you add a microphone. However, it is easy enough to add a USB microphone since the Linux kernel will handle that easily. The pyaudio library gives you an interface between code and the microphone.

We were thinking since the whole thing is a script, it would be easy to also provide some audio feedback. For that matter, you could monitor the state with an e-mail. It might be interesting to provide some other interface — like a web page — that could also switch the load on and off. Or perhaps do different actions in response to two claps, three claps, or four claps. There’s a lot of possibilities.

If you want to know how a real Clapper works, look no further than this. If you want to see a super Clapper, head over to

7 thoughts on “DIY Clapper is 1980s Style With Raspberry Pi Twist

  1. I’ve got one somewhere but have found no use for it. Same reason I don’t have a AmazonSpyBot.

    I do like to “clap off” candles. My wife can’t figure it out; you just have to practice and get a jet of air shooting out of the axis of your index fingers. Maybe I should do a video demo.

  2. I have a similar device from RadioShack (remember them?), but instead of clapping it had a high pitched whistle attached to a squeeze bulb.
    I haven’t tried it since getting a dog, I’m not sure how he’d react to the whistle. but if he found the control, he’d chew it up.

  3. If Ash werent so cute I’d have to blast this project in full asshole critic mode.
    Stuff like:
    PI3 excessive expense and under use. PIZero W IF u can get it but more x-duino or ESP level.
    Glossed over USB mic installation on PI. Most are installed/found easily. Sound sensor modules for duino cheaper and dont need usb interface.
    Output is not clapper. Needs to switch house AC. Inference to “The Clapper” may be reporters soley. LED is how it starts to get there. Then move on to relay, Diac, SCR, Triac, or just cheat it and go SSR. See Current regulating resistor for LED is there more to protect interface/computer than LED. Burning a 1cent LED or 40+$ PI. Though usually just that port pin. Some LED do have builtin. More dont. Red LED typical 1.8-2.2VDC doesnt have a problem on 3V3 but other colors/makes may. Current (mA) draw more the issue. And on and on about that.

    I like it overall but for aspiring Tech writer knowledge and recognizing of Demons in Details is essential. Look forward to more from Ash.

  4. 2019 Version and it doesn’t even use a deep learning network ?! For the same result i would better keep the single op-amp solution, instant boot, no SD corruption and does not need to change the battery everyday

  5. One of my shipmates had the 1984 version. He called it his F*ck Alarm, as he had his VCR connected to it; every time someone said F*ck in a movie, it was usually an explosive word, and so triggered the Clapper, and so stopped the movie.

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