Ok, to get my safe to lock I need something to act as a locking mechanism, The Tech Supplies kit is designed to run a solenoid bolt but what is a solenoid? 

A solenoid in it’s simplest form is a device that converts electrical energy into mechanical movement. It is a coil of wire that becomes a magnet when a current passes through it, the magnetic force then moves the metal core. They are used in many objects such as door bells, car door locks, actuators for model railways etc and there are may different types. Solenoids can have linear or rotary motion, can move the metal core by pushing, pulling or both so which do I need?

I found this animation while looking to see what a solenoid actually looks like and have stumbled across exactly what I need. To act as a bolt the solenoid will need to sit in the safe door and remain pushed out when the safe is locked or off (no point of having it in there if all you have to do to unlock it is to take out the batteries), when the safe is in its unlocked position the power being sent to the solenoid needs to pull it in so therefore I need a ‘pull’ solenoid. To ensure that the bolt returns to it’s original position once the power is cut off a spring is needed to force it back.

Off I go to trawl the world of solenoid suppliers…