Clamp/Arm Mechanical

Hello!

I am currently new to the Arduino but studying Computer Science. As a home project I'm investigating something that will require a form of Clamp/Arm.

The idea being is that the Clamp/Arm will release when it detects a form of signal/no signal.

My question being, where can I purchase a small, mechanical clamp? Preferably very small, very light, nothing too strong.

Or any suggestions for a different method, the clamp will only be holding something very light and will require to let go so the item it's holding can be dropped.

Thanks. Bioshox!

Something like this?

You might try a solenoid; position it so that the plunger (with a rubber tip or something) presses against the item - the other side of the item against a fixed "end-stop". The spring pressure of the solenoid would hold it, and you'd just activate the solenoid to release the item. Quick, easy to build and control, and very little lag when triggered (if this is important). It would depend on what the item to be held is, though (if you could tell us that, it might help).

The arm is going to be used for a Model Rocket.

At each stage of the flight parts of the rocket will be dropped and motor ignited allowing for a ligher aircraft and higher propulsion.

My idea is to hold each part of the rocket with several clamps, but not to make it too heavy or too loose.