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IR Navigation — Parallax Forums

IR Navigation

WombaxWombax Posts: 19
edited 2004-12-31 17:01 in BASIC Stamp
Hi, I'm just starting with BS. I use IR for navigation as described in chapter 7. IR reception is ok but I'd like to know if any improvement is possible in order to have a better response ("obstacle detected" or "no obstacle" without intermediate situations).

Using the SSIR module will improve for better obstacle detection ?

Can anyone help ?
Thx, Luca.

Comments

  • allanlane5allanlane5 Posts: 3,815
    edited 2004-12-31 13:02
    The SSIR module lets you adjust the sensitivity of the reciever (by changing the FREQOUT frequency). This lets you have a few ranges for detecting obstacles.

    However, all of these ranges are very limited -- around a few inches. For a longer range 'ping' you could go to the SRF-04 or SRF-08 ultra-sound module.
  • Ken GraceyKen Gracey Posts: 7,387
    edited 2004-12-31 16:11
    Wombax,

    The range with the Parallax infrared emitters and detectors should be more like a couple of feet - almost up to three feet if the surface detected is reflective of infrared. You can increase the distance detection by using smaller resistors on the LEDs - 220 Ohms or even smaller. The SSIR is the same circuit as what you are using except all of the components are built onto a small PCB.

    The Robotics text includes a simple detect/no detect example of PBASIC code.

    Ken Gracey
    Parallax, Inc.
  • allanlane5allanlane5 Posts: 3,815
    edited 2004-12-31 16:36
    Ken: The SSIR can detect objects 2 FEET away? That's wonderful news, I had no idea.

    Since IR is usually used as a 'whisker' collision avoider, I assumed its range was close. Since you're outputting a signal from the IR LED, and reading its 'bounce' with an IR-Decoder, I assumed the range was shorter than that. Thanks.
  • Ken GraceyKen Gracey Posts: 7,387
    edited 2004-12-31 17:01
    Allan,

    The latest style of IR emitters and detectors can do over two feet. We recently switched suppliers and got a heck of a lot more range. The range varies significantly depending on the surface reflecting the IR. Our office has black baseboards and they trigger about 6-12" from the walls (duh, we should have used a colored baseboard!). But on a light-colored wood surface or painted drywall it detects at a couple of feet.

    I'm pretty certain the SSIRs do the same, unless we've changed the circuit. We have a fish robot (that's right, a robot driven by a Saimese Fighting Fish) in our office which uses SSIRs and they work well with our black baseboard.

    Ken
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