DIY Momentary Switch

Momentary switches are very common, and include the keys on your keyboard.

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Momentary switches are used in lots of electric tools. The buttons on a pocket calculator, the trigger on a power drill and even your computer's mouse buttons and keys are all momentary switches.

These switches are called "momentary" because they usually change a circuit for only a moment, the brief time your finger pushes on it. Some momentary switches, like the power drill trigger or a key on a synthesizer, are most often held down for many seconds. Momentary switches are extremely cheap and common, but you can make your own from a few common items.

Solder a piece of wire to the edge of each penny, one wire per penny.

Any spring-loaded clothespin will keep the pennies separated until you squeeze them together.

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Tape or glue the pennies to the insides of the legs of the clothespin, one penny per leg. The legs are the parts you squeeze with your fingers to open the clothespin. Make sure that when you squeeze the legs, the pennies touch each other, and that they do not touch otherwise.

  • Momentary switches are used in lots of electric tools.
  • The legs are the parts you squeeze with your fingers to open the clothespin.
An ohmmeter will verify your switch's behaviour.

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Touch the probes of the ohmmeter to the ends of the switch's wires, one wire per probe.

Test your switch by squeezing the clothespin while watching the ohmmeter. The electrical resistance should move from an extremely high value to almost zero when the pennies touch.

Use your new switch in any electrical circuit you wish.

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