Inside The Clapper

clapper

Hackaday readers above a certain age will probably remember the fabulously faddish products developed by Joseph Enterprises. These odd gadgets included the Ove’ Glove, VCR Co-Pilot, the Creosote Sweeping Log, and Chia Pet (Cha-Cha-Cha-Chia) as mainstays of late night commercials, but none were as popular as The Clapper, everyone’s favorite sound-activated switch from the 1980s. [Richard] put up a great virtual teardown of The Clapper, that provides a lot of insight into how this magic relay box actually works, along with some historical context for the world The Clapper was introduced to.

Sound activated switches are nothing new, but the way The Clapper did it was just slightly brilliant. Instead of listening to every sound, the mic inside the magic box sends everything through a series of filters to come up with a very narrow bandpass filter centered around 2500 Hz. This trigger is analyzed by a SGS Thompson ST6210 microcontroller ( 4MHz, ~1kB ROM, 64 bytes of RAM, and 12 I/O pins ) to listen for two repeating triggers  within 200 milliseconds. The entire system – including the source code for the MCU – can be seen in the official patent, US5493618.

The Clapper sold many millions of units at a time when a lot of homes were assuredly in a pre-microelectronics world. Yes, in 1986, a lot of TVs had microcontrollers and maybe a washer/dryer combo may have had a few thousand transistors between them. Other than that, The Clapper was many household’s introduction to the ubiquitous computing power we see today, and all with less capability than an Arduino.

Comments

  1. Ray Johnson says:

    I remember working on television seats back in the 60′s. Yes, at one time, there were TV repairmen. The first remote controls that appeared were interesting devices. When a button was pushed, it caused a “tyne” similar to a xylophone to be struck that had a resonant frequency somewhere in the ultrasonic band. The TV of course, had a receiver tuned to the four different frequencies that the remote was capable of emitting; Vol + and -, CH + and -.

    • Jax184 says:

      I believe that would have been the Zenith Space Command remote control. Wikipedia says they came out in 1956. It also says this is where the term “clicker” came from.

      I never had such a set myself, but it was ingenious for its day.

      • Old person says:

        I recall playing with a slinky in front of the Zenith and having the channels switch or the volume change as it occasionally hit the right audio frequency to trigger the circuit for the remote.

      • aboxman says:

        Magnavox had one too. We had an early 70′s or late 60′s Color TV that had one of those. It really never worked well. I inherited when I was in college (late 80′s), and the metal shades that were in the dorms would make it change channels when they were lowered to quick. As a side note, it made a big boom when it was dropped from a second story window when it finally died.

    • Hirudinea says:

      I had one of those as a kid, it was a remote from a TV tossed out years ago, I took it apart and found little metal rods in it and that’s all, and I couldn’t figure out how the hell it worked, now I know. :)

    • Natedagreat6666 says:

      I’ve only been lucky enough to come across the zenith space command remote in an antique place somewhere 10-20 miles from my house, it was a nice concept for the simpler tvs since you didn’t need any damn batteries

  2. The company website for the blasted thing needs our help. It does not want to allow us to find out where to buy its products.

  3. jdraughn says:

    Cool, I just bought one of these from the thrift store. It didn’t seem to work very good though. My dogs running on the hardwood floor seemed to trigger it while clapping didn’t, but I had no idea it actually had a microcontroller in, just figured it used some op-amps.

  4. PirateLabs says:

    I remember The Clapper….Clap on….clap off. Does this make me old?

    Bill

  5. Atwas911 says:

    The Clapper.. Ah yes. How it brings back memories. Brenda I think her name was..

  6. The UnDisbeliever says:

    > The entire system – including the source code for the MCU – can be seen in the official patent

    I could not believe the source code would be involved in a patent application, so I had to check it out myself. Not only do they have a block diagram, but the code is involved as well. I don’t read many patents, but this is the most complete “software” patent I have ever perused.

    Why can’t modern “Software Patents” be this complete? Some of the ones I have read are just ideas that have yet to pass the design phase. This application I could say is a detailed description of an invention.

    Pitty they are cataloged like every other patent and last 20 or so years.

    For the clapper that was a few months ago. Guess what my new project is going to be?

    • HackJack says:

      “Why can’t modern “Software Patents” be this complete? Some of the ones I have read are just ideas that have yet to pass the design phase.”

      You just answered your own question.

  7. “Yes, in 1986, a lot of TVs had microcontrollers and maybe a washer/dryer combo may have had a few thousand transistors between them.”

    I challenge. My current washer/dryer combo, like many past and present (except for some newer “smart” models), uses mostly mechanical elements for timing, and passives for sensing. No silicon at all. HaD, got some links to a washer/dryer from that era with a few thousand transistors?

  8. static says:

    So why all the past tense regarding the clapper? The thing is still for sale

  9. someguywithouthands says:

    finally,
    the ONLY product to “mute” it’s own comercials!!!

    (by mute i mean power)

  10. Casey says:

    There was a very similar device in the 60′s called the sonuswitch – came with a dog whistle – I can not find that it ever hit the market.. The reason I am looking is .. I have an original Sonuswitch in the the original box.

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