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New Sharp IR Sensor — Parallax Forums

New Sharp IR Sensor

ercoerco Posts: 20,255
edited 2014-11-16 15:18 in Accessories
According to Pololu:

The analog GP2Y0A60SZ sensor outperforms all of the other analog Sharp distance sensors we know of, offering a wide detection range of 10 cm to 150 cm and a fast update rate of 60 Hz in a small package.

http://www.pololu.com/product/2474

Great! Right after I stock up on their now "has-been" sensor!

Comments

  • GordonMcCombGordonMcComb Posts: 3,366
    edited 2014-11-14 22:54
    Well, the sensor itself is not new, but for whatever odd reason, I think this is one that Sharp embargoed for US sales. You'd go to their Web site and it would say "not for sale in the US." Harumph! If this was indeed one of the devices formerly not available here, I'm guessing whatever limitation there was has now expired.

    I like that Pololu is finally getting the idea of putting mounting holes on their small breakout boards. Two holes would have been better, though, to lock the thing in place without over-tightening the lone screw. They have this thing about making everything teeny-tiny, even if it doesn't have to be so small.
  • dgatelydgately Posts: 1,628
    edited 2014-11-15 11:48
    3 volt version: http://www.pololu.com/product/2476

    dgately
  • varnonvarnon Posts: 184
    edited 2014-11-15 20:37
    Oh I like that. I have a project that has been put aside for a long time that needs a bunch of IR sensors. These would be great. I love the form and the inclusion of the mounting hole in the board.
  • DomanikDomanik Posts: 233
    edited 2014-11-15 21:58
    As someone that’s new to IR detectors I’m curious about how they work. I looked through the datasheet and have some pretty basic questions about how it would be used in your projects. It looks like it would normally be used in the continuous mode where every 16ms it updates the voltage on the output pin. In the triggered mode you’d need to wait 16ms + 4ms to maybe have a valid reading.

    The distance to voltage response is not linear but a curve that has a very small change in voltage as the it reaches its maximum distance. In the accuracy spec it has a significant min to max range of 0.5 volt and that amount changes with distance. Do you calibrate these individually before trusting the measurements?

    Seems like some math and characterization would be involved to get accurate measurements.
    Thanks,
    Dom..
  • GordonMcCombGordonMcComb Posts: 3,366
    edited 2014-11-16 07:49
    Although billed as distance measuring sensors, they're really intended for "distance detection" applications where specific distances are preset in software or analog comparator hardware. Examples are automatic faucets, where the faucet will turn on and off if the detection range is within a certain distance, say 8 inches. It really doesn't matter if it's actuyally 8.25", or 7.75" inches. They set the range based on the physical conditions they want. Other process control applications include detecting when materials go by on a conveyor belt. The detection range is likewise set empirically.

    The output curve may not be linear, but is predictive, and in most hobby applications no correction is needed. Otherwise, there are some formulas and tables people have developed that can be used if you need a little more accuracy.
  • ercoerco Posts: 20,255
    edited 2014-11-16 15:18
    There are cheaper digital output IR proximity sensors: http://forums.parallax.com/showthread.php/157415-Laser-Free-Reflector-Sensor-Uses-IR?p=1294508&viewfull=1#post1294508

    Check my last post in that thread about swapped pots. Triggering range is adjustable up to about 10-12 inches, but they are somewhat sensitive to color.
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