2 position servo/stepper motor

[breguetphile]

For a project I'm working on I need some sort of motor that is either on/off and rotates 180 degrees from its original location when on. While I could achieve this with servos or stepper motors and a micro I will be needing around 30 them so I would like to keep the cost as minimal as possible. I just figure there has to be some simple electromagnet/spring combo or something out there. It just needs to rotate back and forth between two positions 180 degrees apart when I feed it power. Simple right?

Thanks.

[Magura]

Originally posted by breguetphile
I just figure there has to be some simple electromagnet/spring combo or something out there. It just needs to rotate back and forth between two positions 180 degrees apart when I feed it power. Simple right?

Thanks.

You figured right

It's called a soleniod. Such a thing can have either rotating or liniar action. You see them frequently, for instance in older hard drives and the like.

Magura

[breguetphile]

Ok, naturally I must ask, any idea where I can get some for cheap? They don't have to have much torque. Enough to spin a lightweight wooden blade about 3x1x1/8". Can't find anything cheap on digikey or mouser. As I'm not much a mechanical guy I'm not sure where you'd source something like this.

Thanks.

[Magura]

You can find such in old hard drives (hard-discs), besides that I guess such would be to find in a floppy drive as well.

They don't come for cheap anywhere, besides a lucky shot at ebay maybe that is. I would guess that such would set you back at least 20 USD a piece, but give ebay a shot. Maybe one of the native speakers could help out with what else they could be called in english, as I'm sure you'll need all the help you can get to find such on ebay, though I'm sure they are there....just gotta figure out what people have listed them as.

Magura

[breguetphile]

If this is the case why are servos, that they would use for steering in cheap remote control cars, so much cheaper? Surely theres something that I can use thats closer to a dollar or two in cost.

Even if its cheap plastic casing and shaft.

[davesaudio]

so whats wrong with using a toy motor and a spring?
maybe feed it a lower voltage or limit current so it can't burn itself out when on

[breguetphile]

I was originally thinking of using a motor with a stopper, but i've got to think there's a better solution out there somewhere. Its just to turn a very lightweight blade 180 degrees and back. Fairly simple criteria, figured there had to be some commercial part that could handle the task for cheap.

[Magura]

This is the cheapest off the shelf I know of:

http://uk.farnell.com/jsp/endecaSear...=530232&N=401#

You would have to make a link to make it a rotary action type, but compared to the price of the rotary action types, that just might be the right solution anyway.

Magura