When sending information from a sensor that’s mounted on a rotating component, the options are normally to use slip rings or radio telemetry. I found that both these techniques have limitations and therefore developed a very cheap and simple optical telemetry link. By connecting an IR diode between the PWM output and serial output pins (via a 180 Ohm current limiting resistor) it possible to produce a 38KHz modulated IR data stream from the PICAXE. Data is interfaced to a PC serial port using an IR receiver and a single buffer transistor. The range is in excess of several metres at a data rate of 1200 baud.
The emitter diode was a TSUS4300 and the receiver was a TSOP4138, both operate at 950nM. The only potential problem is that the receiver has an automatic gain control loop that is pattern sensitive but in practice the link is quite robust over a wide ambient light range. This type of optical telemetry could be useful in many robotics applications, like measuring torque on a drive shaft.
The emitter diode was a TSUS4300 and the receiver was a TSOP4138, both operate at 950nM. The only potential problem is that the receiver has an automatic gain control loop that is pattern sensitive but in practice the link is quite robust over a wide ambient light range. This type of optical telemetry could be useful in many robotics applications, like measuring torque on a drive shaft.