I need to control an RC servo via an IR link to a PC serial port. Is anyone aware of a schematic of a transmitter and receiver for this? I'm not familiar with IR chips and the like.
The problem is that I built an experiment that has rotary solenoids mounted on a rotary platform powered by a two conductor slip ring. It was later realized that servo control of the actuators are necessary. Perhaps I can avoid making another slip ring with three conductors and instead use an IR link.
Very do-able. We have an 8-pin 455kHz IR signal generator IC here
1 x TX-IR IC
1 x 20MHz crystal or ceramic resonator
1 x 870nm infrared LED
1 x TSOP7000 High-Speed 455KHz Infrared Detector Module
We've used this IC to build IR wireless serial LCDs, wireless robotics communication systems, data-loggers, and IR control of up to 16 servos from a PC serial port at up to 60+ from the PC with serial servo controllers like the Seetron Mini SSC-II, and several others. Using a single IRLED. If you need better distance just drop in a few more IRLEDs.
Look on the lower section of the above page for schematics.
I suspect it would even work directly connecting the IR detector output (using the above inverter circuit) to your servos control input as well if you had something to input your servo control pulses to the TX-IR.
The high-speed GaAlAs IRLED (a must for high-speed data-rates) with the TSOP7000 allows up to 19,200bps data-rates for serial IR communications.
Here's another schematic you may also find useful for the PC/IR interface.