pictures that follow are "clickable"
This project, called "Maxi-Switch", is a miniature programmable R/C-controlled, high current Solid-State (all electronic) switch that is based around the PIC microcontroller and an n-channel Field Effect Transistor (FET). Basically, the circuit works by the PIC monitoring the R/C servo channel output signal (pulse widths) and when a certain servo signal position is measured, it triggers the gate on the FET, allowing the FET to control high current loads.
Before the circuit is first powered up (servo wire connected to R/C receiver), you need to be sure that your R/C transmitter is powered up and the controlling switch/stick/slider on the transmitter is in the proposed OFF position. When you then power up the circuit (if connected to an R/C receiver, the receiver is powered up), the PIC will first measure the current servo signal, assumed as the OFF position) and automatically calculates the ON position (usually, 60% of opposite stick/switch/slider position). When you then move the stick/slider/stick past this 60% point, the FET should trigger, turning on your load. To turn off your load, move the stick/slider/switch to the original OFF position.
There are also some interesting FETs called HEXFETs
(by IRF) that have very low on resistance with high current handling
1) Design a simply and cheap programmable R/C switch
that can control large loads (20+ amps)
(1) PIC 12F629 Chip (preprogrammed with Maxi-Switch hex code)
SORRY, The Maxi-Switch PIC Hex Code can not be freely distributed... sample code might be made available in the near future so check back here often...
Q1. I'm looking to build my own Maxi-Switch using your circuit. Can you provide me the PIC code so I can burn my PIC?
A1. Sorry, the PIC code is not freely distributed as this is the only way I can recoup (monetarily) the time and effort I spent in developing not only the PIC code, but also the time spent designing the circuit, the printed circuit board and the time spent building and hosting this webpage. I can though sell you a pre-programmed PIC for any of my projects. Please be warned though that all pre-programmed PICs I sell are code-protected, in that you will not be able to read the Hex code using a PIC programmer. Attempting to do so could damage the PIC and/or possibly erase the hex code.