Hello all,
I'm looking for a distance sensor to be used in a situation where I need to mesure the distance from the sensor of an object moving toward or away from it without noticeable lateral movement (and I don't want to measure it anyway). The object is always different but all possible combinations are showing an almost flat square surface of 20 centimers side and cannot be tempered with so the sensor has to work on its own.
With this measurement, I want to give feedback (visual, audible, to a supervisory system...) of that distance considering that anything closer than 5 centimeter is considered "too close" and anything farther than
200cm (approximately) is considered "too far".I don't need great precision, and if I was to use an ADC for reading the analog value, 8 bit would be enough giving me a resolution of roughly
1cm. Note that I would prefer a linear sensor but it doesn't have to be. For instance, it could be that the greatest precision is obtainable between 5 and 100cm (80% of values for instance) and less precise farther than 100cm. I would need however to distinguish between the "too close" and "too far" states.As the system will have to run on batteries in most installations, I would like it to consume as little energy as possible with the possible help of microcontroller turning it on and off on a regular basis. Having a microcontroller on the board is almost granted for the whole system to work, so it should not be a problem to add the management of the sensor.
For this kind situation, I know of laser, infrared and ultrasonic sensors but I'm not sure what would be best suited considering the "low current" requirement. Nor do I know if there is a better kind of sensor.
So if anything comes to mind to anyone, please do not hesitate to point me in the right direction.
Regards