Im planning to build a drawer which can be opened using an electric switch. Ive thought of perhaps using a strong servo to push the drawer, hydraulics or an electromagnet. But i think the simplest and cheapest solution would be to attach a strong magnet on the back of the drawer, and setting up a wire with a high current running through it behind the drawer. This current is controlled by the electric switch. When the current is on there will be a magnetic force acting on the magnet, and thus on the drawer. I know that the force on the drawer from the wire needs to be about 20N or more. Does anyone know how strong of a magnet i must buy, how high the current must be?