I am interested in using an IR receiver (as opposed to a standalone PIN photodiode or phototransistor) to measure distance/range. I thought I had found an appropriate match in Vishay's TSSP4P38 mid-range proximity sensor, which varies its pulse width with reflected signal strength. These, however, seem to only detect changes in distance as stated in p.3 of this document from Vishay; also, it's reflective and I want to be able to detect the distance (and possibly bearing using an array of IR detectors) from an IR emitter as depicted in the image below.
After my search, I have found only Vishay offers an IR receiver capable of outputting "analogue" information; is there an alternative IR receiver capable of measuring absolute distance I have overlooked? I would like to exhaust my IR receiver options first, before I look into using a photodiode/phototransistor which will require extra circuitry, such as amplification, filtering and demodulation.
Additional information: Range of ~2m to 3m and not too sure of accuracy and resolution at this stage, but possibly within ~10cm @ 3m.
Best Answer
You can't use light like that to measure distance. Think about how long it would take light to travel 10cm, and then you'll see what you can't use that to measure distance.
All IR receivers give you 'relative' distance because they can only measure relative distance as a function of relative change in received light intensity, which makes your measurements dependent on a number of environmental factors.