Hi all,
I don't know if what I'm looking for is even possible, but I'm looking for something like a reversed electro-magnet: a magnet which is normally on (without using power), but can be turned off using an Arduino. I'm going to use it to hold a box lid closed against a little force (something you'll need to pull hard to open while the magnet is on).
Does anyone know such a product, or of a way to temporarily turn an ordinary magnet off using electric current?
Thanks a lot!
Maybe the simplest solution would be to use a permanent magnet and an electromagnet with an iron core: When the electromagnet is off, the iron core will be attracted to the permanent magnet, when you turn on the electromagnet, it will repel the permanent magnet. As a bonus, you could also reverse the voltage across the electromagnet to attract the permanent magnet, to keep it closed even harder.
What about using a regular permanent magnet and a servo to withdraw it far enough not to have any effect?
...R
You can find reverse EM's
Some are "through EM's" which means they can be used in two directions as a "shuttle"
Some also have spring returns which can in some cases be used to keep the pole in a set position.
Some even have dual poles with a centre position at zero voltage.
I would suggest you look a little further into "electro magnet arduino" on google or such.
PieterP's suggestion is also an excellent one.
Perhaps something like this would work for you:Magnetic switchable device - Wikipedia.
If you removed the detent, the magnet would turn easily. Then figure out a way to have an Arduino control it.
Paul
Thank you all very much! I'll look into all your proposed solutions
You're describing an "Electropermanent Magnet". Google the "OpenGrab" and you'll have what you're looking for.