This was my first use of arduino as well as soft circuitry.
The concept is that two panels of conductive fabric were arranged on the palm with a space separating them. They were connected to the same circuit, which was monitored by an arduino. When the hand clasp itself, objects or ‘high-fived’ other hands, it would press the conductive panels together and complete the circuit. The arduino would recognize this, and turn on a small led to register that the circuit was working.