RangeFinders: IR vs. Ultrasonic

[Colin Small]

We're looking for a rangefinder for our robot for use for getting the right distance from the wall to shoot from. Now, I've done some research and found that the IR sensors are good when you have no ambient light (which would be the case indoors in the stadium) and Ultrasonic are more accurate. More accurate would be better, and I've been having troubles locating a good IR sensor that's no too expensive that gives us a minimum range of around 20 feet. As far as utlrasonic goes, we found the Maxbotics MB1240, it looked like it would work great. Unfortunately, we don't know if we should go with an IR sensor in fears of interference from the Ultrasonic Sensor (other than other robots, I can't think of other possible causes for interference).

[AllenGregoryIV]

For long distances (more than 3ft or so) most teams have used Ultrasonic sensors for FRC applications.

[mman1506]

The (sharp?) IR sensors are fairly outdated tech, the maxbotix sensors are much more resistant to interference and accurate than a IR sensor.

[Colin Small]

Then the MB1240 is what we'll go with. Can you angle them upwards to try to avoid our bumpers (due to our design layout; a rangefinder wasn't in our original design)? Sound isn't a strait line, so wouldn't it mess up the sensor if you don't have it flat?

[electroken]

Originally Posted by Colin Small

Then the MB1240 is what we'll go with. Can you angle them upwards to try to avoid our bumpers (due to our design layout; a rangefinder wasn't in our original design)? Sound isn't a strait line, so wouldn't it mess up the sensor if you don't have it flat?

Look up the data sheet for the MB1240 and you'll find it has a very narrow beam angle. In fact, it's the most narrow of any of their sensors. What that means is if it isn't aimed right at the wall you'll get very little signal back.

The angle of incidence = the angle of reflection, and all that.

[Colin Small]

Originally Posted by electroken

Look up the data sheet for the MB1240 and you'll find it has a very narrow beam angle. In fact, it's the most narrow of any of their sensors. What that means is if it isn't aimed right at the wall you'll get very little signal back.

The angle of incidence = the angle of reflection, and all that.

I know, but all it's going to be used for is to aim at the wall. That's the reason I chose the MB1240. I don't want interference from other robots.