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IR Dist. meas. using OPAmps to give analogue rep of dist-req

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phluxor

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Hi all

Im trying to build a distance measuring cct using infrared. My goal is to somehow represent the distance of an object from the IR sensors with voltage signal that is proportional to the distance between the sensor and object. I'm working off a 0-5V source. My plan is to use a PIC to detect the change in voltage levels and thus determine the length. I'm trying to avoid pre-built modules due to cost and availability.

If any of u guys have any suggestions for a course of action I'd really appreciate it!
 

Re: IR Dist. meas. using OPAmps to give analogue rep of dist

How accurate does it have to be?
 

Re: IR Dist. meas. using OPAmps to give analogue rep of dist

im looking for around 1 to 3 cm accuracy. Do u have any circuitry in mind that will help me?
 

Re: IR Dist. meas. using OPAmps to give analogue rep of dist

measuring to a brick. im building a robot. planning on detecting bricks placed at random points along a path
 

Re: IR Dist. meas. using OPAmps to give analogue rep of dist

phluxor said:
Do u have any circuitry in mind that will help me?
It's also about optics in adition to circuitry. Circuitry is an easy part.

Only a triangulating IR sensor can accurately determine distance to a brick, if you approach the brick at an abitrary angle. The principle of operation of such sensor is described in some detail here:
 

Re: IR Dist. meas. using OPAmps to give analogue rep of dist

thanx, that clearedd up some things. But is there no way of rather detecting the intensity of the reflected light and using that information to determine distance. im trying to make this out of discrete components, the pre built ones are bit expensive...
 

Re: IR Dist. meas. using OPAmps to give analogue rep of dist

phluxor said:
But is there no way of rather detecting the intensity of the reflected light and using that information to determine distance.
You can use the reflected light intensity only if you always approach the object at the same angle.

IMHO, an ultrasonic ranger is easier to build from scratch than a triangulating IR ranger, because the former doesn't require optics.
 

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