Microwatt Pulse Motor

DIY extremly low current pulse motor from old relays

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This is a pulse motor that is easy to build because it uses ready-made coils made from relays from an old electromechanical telephone exchange. Also can be used coils of any small relay or other device.

  This motor has several different modes of operation presented in the pictures

   1.Pulse motor with Reed Switch powered with salt water battery.

2.Pulse motor with Reed Switch powered by "potatoe" battery.

3.Pulse motor with Reed Switch Powered by electrolytic capacitor in motor-generator mode.

4.Pulse motor driven by two transistor circuit without reed-switch.

 5.Continuous rotation Pulse motor with solar cell and lithium battery.


Solar cell pulse motor schematic

JPEG Image - 556.40 kB - 05/22/2020 at 15:04



Two transistor pulse motor schematic

JPEG Image - 557.92 kB - 05/22/2020 at 15:03



reed switch pulse motor schematic

JPEG Image - 569.85 kB - 05/22/2020 at 15:02


  • 8 × Coil from old relay
  • 1 × 1000 MicroF Electrolitic capacitor
  • 1 × 5V Solar cell
  • 1 × NPN transistor
  • 1 × PNP transistor

View all 7 components

  • 1
    Step 1

           The construction is very simple and is basically based on the idea of Lasersaber pulse motors , which have probably achieved the best results in terms of low power consumption. I am pleased that this motor gives comparable results to its, although it is made of old ready-made materials in a very short time.

           As you can see on the picture the schematic is very simple. All eight coils are connected in series. The reed switch is also connected in series with coils.

      t is very important that the success of the device very much depends on the position of this reed switch  And it is determined experimentally depending on the model of the reed switch. Extremely low consumption is due to the design as well as the way the axle is set. In fact, one end of the axle floats using a small magnet so that friction is minimal. This motor can also operate without a reed switch, with the help of a circuit consisting of two transistors and one variable resistor. By changing the resistance of the potentiometer, the current through the coils changes, and thus the speed of rotation of the motor.

        In the video that follows you can see how all the modes of operation of the engine work, as well as a detailed description of its construction.

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aaaaaa wrote 04/15/2023 at 17:59 point

nice but not usefull, can You modyfy shewing table to make electricity for example lamp? table with big wheel and foot powered working.

Foot Operated Table for example singer

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Starhawk wrote 09/19/2020 at 17:03 point

Looks fairly intriguing... only one small request, a documentation type thing.

Can you put up an explanation, either in "Details" or in the "Description" field, as labeled, as to what an electric pulse motor is, how it's different from other motors, advantages over conventional brushed and brushless motors, and a simple "how it works" explanation?

I can find nearly none of that online, and I really feel like I'd be even more interested in this project if I understood it properly.

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Alexander wrote 08/03/2020 at 16:16 point

This is super cool! Exactly what the Tech at Home contest is all about -- using things you have at hand to build something cool! :D

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mansel wrote 05/28/2020 at 06:24 point

Great project with clear instructions and pictures. Well done mate.

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Mike Szczys wrote 05/26/2020 at 21:35 point

Very cool thing to have sitting on your bench/desk. Especially since it can run form solar. Although running it from a potato is a fantastic party trick!

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