MK I (lo-tech prototype and proof of concept)

Very basic functionality for accuracy training.

Parts:

• 1 x scrap piece of wood
• some empty beer or soft drinks cans
• nuts & bolts (one of each per can)
• 1 x LED 
• 1 x resistor (depends on LED)
• 1 x capacitor (for LED persistence)
• battery (low voltage to drive LED)
• wire to connect the targets   
• wire to connect to epee or other weapon (only one pin is used)

Cost:

• a few pennies (unless you include the cost of the beer)

The target is a few drinks can bases that are bolted to a board, in this case a bit of leftover melamine shelf: 

On the back face a wire connects all the bolts electrically.

A single wire connects the centre (or near) pin on an epee to the circuit.

The electric circuit comprises a battery and LED in series, and a capacitor across the LED.

The wire from the weapon connects to one leg of the LED, the other leg is connected to the battery +ve, and the battery -ve is connected to the target wire.

Pressing an epee's tip or touching with a sabre completes the circuit and lights the LED.

The capacitor means that the light dims slowly rather than just being a blink.