Hello People,

I was wondering if you guys might have an idea for a project I'm working on. I've made a solenoid that attracts a thumbnail when powered with a DC battery. But I want the thumbnail to oscillate, so to go back and forward. Is there an easy way to automatically switch the current on and off? Preferably not too big or expansive? (The coil requires 0,65A).

Thank you for your help in advance.

 

You don't say how fast you want this movement to happen. But one way to do it would be to use contact points on the plunger. Like in the old time doorbell ringer, like here - https://gbsphysics163.wikispaces.com/How+do+doorbells+work+(Abbey)

 

Thank you for the response. Yes, that might work. Guess I'll try that one.

 

If you want the plunger to cycle at a slower rate you would pulse the coil. As it is now when your current is applied the plunger pulls into the coil and will remain there as long as current is applied. When the current is removed the magnetic field of the coil collapses and the action of the spring returns the coil to where it started from. If we "pulse" the coil at a given rate then the coil will pull in, HOLD, release and the cycle will repeat, all determined by the pulse rate or pulse timing. The coil could be On for 1 second and Off for 1 second and repeat or On for 1 second and off for 2 seconds and repeat. Doing it this way will require some external electronics. So there we have another option.

Ron

 

have a leaf spring contact in the travel path of the object you want to attract. When it moves toward the electromagnet, it will contact the leaf and break contact. This de-energizes the magnet and the object returns to its starting point. The leaf spring then closes and the cycle repeats