Solenoid Motor From A VCR Head


Here’s a solenoid motor you can build from a VCR head and some common components. It uses an LED and a light sensor, paired with an LM311 comparator to manage the switching of the motor. As the head turns, the LED shines on the sensor through a hole and triggers a TIP120 transistor to turn on the motor during the power stroke. Once the beam of light is broken, the transistor turns off the motor and the momentum carries it through its revolution until the next power stroke is activated.

We often say that “why” is the wrong question. [Bd5940] must feel the same way because he ends the video by saying: “it has no use, but definitely a conversation piece”. Yep, we’ve seen that before.

[Thanks James]

14 thoughts on “Solenoid Motor From A VCR Head

  1. could totally use this in some form of a steampunk type of hack. maybe a fan of some sort. Reminds me of the old style belt driven fans they used to use in hotels. one motor driving 3-4 ceiling fans all with belts.

  2. Solenoids aren’t usually used to open and close in rapid succession, right? I think the advantage of a solenoid is that you can generate a lot of torque in a linear direction (like locking or unlocking doors).

    I know he said it has no use but, I’m not even sure how to describe what he did. It’s like a linear actuator that might be more efficient because it only uses power during part of its cycle?

  3. @andrew: I think this would be much more efficient if an AC drive was used to power the solenoid. Sync the phase with the crank position to get max output vs. input. Inductors in general are rather poor in therms of on/off (square wave) operation.

    Neat idea, but would still be useless.

  4. My Marklin erector set from 50 years ago had this in it – it had a comutator disk so the power ‘phase’ of the solenoid could be adjusted – I guess what’s old is new again.

  5. “lol, I’m I the only idiot that jumped when watching the video and he’s states he going to give it a spin. that was a loud burst. XFD.”

    no I jumped a bit too

  6. CdS cells have a relatively slow response time, around 50ms IIRC, he should use a phototransistor instead. Also the stroke is about 30 degrees too early.

    Otherwise, a fun thing to build, I might make one myself with that VCR that’s been sitting on my shelf for the last 15 years.

  7. Nice project!

    This may sound stupid, but what is the name for that white construction material everybody uses? I have seen it many times before in these kind of projects, but can’t seem to find it in DIY-shops here (Belgium)…

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