I need to transmit my measured data of torque and temperature (measured using RTD and strain gauge) from a Rotating shaft running at 7500 rpm through IR communication. Is it possible? does line of sight become a problem? Does the device (transmitter & receiver)needs to be stable for IR data transfer? Will the fast running shaft be a problem? how to accomplish this?
Is it possible?
My company uses infra red laser diodes to transmit telemetry data off shafts at data rates up to nearly 700 mega bits per second so there is nothing inherently flawed in this method however, at this sort of speed photodiodes and their amplifiers need to be carefully designed and you do need pretty good alignment.
does line of sight become a problem?
So, assuming you can place the transmitter at the centre line of the shaft-end you should be OK. Lower speeds mean you can use fast LEDs and less problematic (and more sensitive) photodiodes.
Does the device (transmitter & receiver)needs to be stable for IR data transfer?
Stability = no loss of data
Will the fast running shaft be a problem?
Yes, you will need to mechanically balance your add-ons and make sure they can withstand the g-forces. We always make sure that any PCBs are subjected to g-forces that push components towards the PCB they are soldered to (at distances close to the shaft centre-line this is far less of a problem of course).
how to accomplish this?
That's a money question LOL.
Don't forget that you need to supply power to the electronics mounted on the shaft - a battery may be OK but you will need to mount it as close to the centre-line of the shaft as you can AND watch out for imbalances.
A typical car tyre will rotate at about 1400 rpm at 100 mph so balancing is a really big deal.
You've got 120 or 130 revolutions per second. If you transmit ONE BIT per revolution, with 2 measurements of 10 bits or 20 bits total to transmit, you can transmit 6 complete measurements per second.