A radio-controlled power switch for models and other devices

This radio controlled (RC) model switcher has been designed for use on a spare RC transceiver channel to effect on/off power switching to an RC model or other device. The maximum switching current is set to about 1·0A, at a safe maximum supply voltage of 24V d.c. A larger current could be controlled with the additional use of a relay.

The point at which the unit’s output switches state is known as the trigger point. Once the incoming pulse width exceeds a preset value, the switcher’s output is switched on. If the pulse width is below this threshold, the output is switched off.

The author’s previous designs for RC switchers included a number of monostables to control the circuit trigger timing. These circuits had no hysteresis and were prone to jitter at the trigger point. The circuit presented here is PIC controlled and has been designed to avoid this problem, and to generally improve performance and reliability.