I made this detonator with $10 worth of parts and about an hour of build time.
Parts.
2"+ 3" black plasic project box.
one toggle and one slide switch.
9 volt battery and clip.
Red LED and voltage reduction circuit (Made the circuit myself).
machine screws and 24G solid core wire.
Inside view.
diagram of the circuit.
Its very easy to make, here are the results of my work.