I've been making plan for an obstacle-avoiding robot, and was originally planning to use a Sharp IR range finder for it (10 - 80cm), but after seeing other sonar range finders, and other people's projects (the majority of the ones I see seem to use sonar), I was wondering: Which …

The major downfall to each is … IR can have issues w/ colors and some surfaces and sonar can have problems with narrow objects. One book I have read commented that a robot’s senses should degrade gracefully. Given a chance depending on your environment using both types along wit…

Sonar sensors do have one Sonar sensors do have one problem that I noticed. When you try to measure the the distant to an object that it at an angle, the sound waves do not come back to the sonar, as in the robot reads it as an infinite distance even though the object is only …

Generalizations are always wrong, but… I will offer some up anyway. IR seems to be preferred at small distances while the sweet spot for ultrasound is a little further out. Ultrasound has various cone shapes available (wide versus narrow) and IR pretty much needs to be a beam to…

Cone shapes? What exactly do you mean by cone shapes? Is that referring to the beam width? 'Cos when I was looking up sonar sensors earilier, and when I looked up IR ones, I cam across charts like this (comparison chart of sonar sensors): http://www.pololu.com/picture/view/0J196…

For most practical uses, For most practical uses, light has a bean width that is fixed for the whole range while ultrasound spreads out as it gets further away, causing a cone shape instead of a beam. I am not sure I have this right, but I think they narrow the ultrasound cone b…

Forgot to say what the charts mean Those are the cones for different models in the first 2 columns. It tells you how wide the detection area is at different distances. The 3rd column is showing you how many false readings you get. Getting a cheap sensor and hooking it up to an A…

Thanks Ok, thanks for that. So for example at distance x, the beam has a width of y, and would reflect back (in theory) from an object in that width. I will test a couple of sensors with that, I just wanted a bit of advice as I do not actually have a sonar sensor or an analog se…

Hmmm I just tested a couple of digital Sharp range finders ( http://www.littlebirdelectronics.com/products/Sharp-GP2Y0D805Z0F-Digital-Distance-Sensor-5cm.html ) and while in the site description it says they will return a logical 0 if an object is from 5cm to 0.5cm away, and if …

Yes. I would look at Yes. I would look at these: http://www.trossenrobotics.com/c/robot-IR-sensors.aspx what I am testing is a knock off of the middle one.

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IR v. Sonar

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arbarnhart January 24, 2011, 8:17pm 5

one more from the last few minutes…

Both have a hard time with fabric, but I think IR has an edge. Neither is failing totally on my blue cotton shirt, but I am getting a lot of false readings from both.