The radio system is Arduino powered using the NRF24L01+ 2.4GHz radio modules. On the transmitter side, there is a master power switch, 10k pot, two led indicators, Ardunio, and 9V battery. Both switches provide a simple on/off function. The NRF24L01+ transmits the on/off state of the 10k pot. One led is a power indicator and the other is a gas on/off indicator. On the receiver side, there is a master power switch, Ardunio, two led indicators, and 9V battery. One led is a power indicator, and the other is a connectivity indication. There is an interlock/failsafe function in the receiver code that will turn the gas off should connection be lost. Two 9V lantern batteries, wired in series, provide power to the servo. There is a L7805CV 5V voltage regulator attached to the servo power line to reduce voltage to the servo. The Savox SA-1230SG servo is rated at 416 oz/in torque@4.8V. It can tolerate up to 6V. Any less than 390 oz/in is not enough torque to pull the handle. Having a little more than this, and providing a little less power than the maximum the servo can handle is a good compromise between having enough power without burning out the servo. Everything fits nicely inside some SparkFun project boxes.