Triangulating position of a laser between three photocells.

Other Hardware Sensors
1

Hi all.

Im trying to determine the position of a laser point between three photocells similar to this one: Mini Photocell - SEN-09088 - SparkFun Electronics

As of now I have built a testing environment that has three sensors beneath the surface of a sheet of paper that helps to disperse laser light so that I am able to see the resistance feedback for each fluctuate on my serial line as I move the point across the paper.

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What I would like to do is to be able to determine where the point is within, or around, the triangle of photocells using the feedback from each.

Im very new to arduino -- this is my first project -- and Im sorry if the question is too broad/misguided. Any feedback or reference to existing work in this area would be fantastic.

2

First step would be to create a function that computes the distance of the LED point to a single LDR from the analog reading of the LDR. On your piece of paper I would lay down markings from the center of a single LDR at ~5mm intervals, point the laser at each point, and record the analog reading. I'd throw these values into a spreadsheet and then calculate the "line of best fit" (a feature in both Excel or OpenOffice) to generate the function.

Given the above you should now be able to calculate the distance of the laser point to each LDR you would use trilateration to calculate the location of the laser point. I think I'll leave that to you and Google to figure out :wink: