The robot uses a 12 V DC liquid pump to put out the fire by spraying 100 mL of water onto it. This pump is switched on through a MOSFET and uses a nozzle array to maximize coverage.
Real Flame vs Decoy
The robot will only spray water on a real flame.
It will not spray water on a decoy.
It is able to tell the difference between the two using a temperature sensor because the flame outputs heat but the decoy does not.