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Distance Measuring Sensor Advice

  1. Oct 12, 2012 #1
    Hi There, I'm looking for ideas on finding the position of objects (such as a hand or foot) placed in a tank. Without using a camera soultion, I think the use of something like a minature laser range finder or IR proximity sensor. My problem is that I need to find distances between 5cm (min resoultion) and 85CM - ideally on one angle (90degrees from mounting plain). As I said, the accuracy needs to be min 5cm resolution.

    Has anyone got any advice on devices/sensors I can use. My plan would be to use such sensors on two sides of the tank (x,y - no need to get the depth) Althought the IR ones may work I dont know whether they provide 5cm resolution

    Thanks in advance,
  2. jcsd
  3. Oct 12, 2012 #2
    what about acoustic ranging?
  4. Oct 12, 2012 #3
    You don't say if the tank has material in it.

    If not, then an ultrasonic sensor with analog output may do nicely.
    Or a series of inexpensive photoelectric through-beam sensors.
  5. Oct 14, 2012 #4
    Thank You DragonPetter and tygerdawg for your suggestions. FYI, my tank contains water, and has a set of red dot lasers and phototransistors on two sides each to calculate the position. the problem that I wanted to solve by using a separate sensor(s) was inability to counter occlusion when two objects are inserted. The secondary sensors I am looking for are to be placed above the water surface (10cm above) of the tank. I think the acoustic sensors will pick up the water surface as a object so perhaps the IR is the only solution ?.
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