There are tiny 12V batteries that they make for garage door openers. Using a simple NPN transistor, you can switch the 12V source from the battery to a common ground with you robot, from the robot's MCU. I have one of those batteries, it's a Duracell, and says "MN21/23 12V" on the side. It's the same width and half the length of a AAA battery. I think they're referred to as an A23 cell.
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Sounds cool.. I'd be tempted by a servo, but no doubt there's a good reason against using one... Will a charge pump do?
Yeah, a servo would make it too heavy, and i can't be bothered adding the stuff for it and it's not supposed to be a permanent attachment, it's supposed to be able to be taken off so i can use the bot as a mini sumo. Unfortunately we don't get many mini sumo competitions here in Australia. What's a charge pump? Sounds to me like a type of solenoid. No pneumatics please!
A charge pump is a kind of circuit that (as far as I understand) uses a few transistors and capacitors to provide a different voltage to what is put in. Here's the wiki ( Charge Pump on Wikipedia ). There is one example that comes to mind in the form of a BEAM kit from solarbotics if you click the resources tab there is a document that on page seven gives a break down on how their "voltage doubler" works (I believe this is a flavor of charge pump). It will only work for short amounts of time (depending on the solenoid - it may have to be quite beefy in terms of big capacitors though) but if its an aesthetic thing you could set up a BEAM circuit with a voltage doubler to act as both control and driver. The document is well worth a read I think, It really is quite wonderfully informative. Hope this helps, Drew
6v will probably drive a 12v solenoid, just not terribly well.
Add a 12V source and a relay (or amplifier if you need analog control rather than on/off).
Or replace that solenoid.
yeah i was considering a relay. im just a bit rusty with them though. do you play 40k?
it probably depends on what your doing with the solenoid, Is there any way you can get around using it?
i'm creating a clapper type gripper in the shape of a mouth for my robot. its the most simple idea.