Robot Sensor Horn for Sharp IR Sensors

thingiverse

I designed this sensor horn in order to implement a very simple mapping algorithm on a mobile robot. This allows you to see all 360 with two sensors and a standard micro servo(I got mine in a ten pack off ebay for not much at all) in one 180 degree rotation. I had this made out of wood originally. It wasn't very good. Now that I have a ToM, I'm excited to improve upon my design. I'll mark this complete when I get it to print without having to use my dremel drill press. I also need to replace the belt on my ABP, I rigged it with a layer of kapton tape for this print, but it still ended up a little warped and weird. Then there's a mountain of things I could do to tune my printer as well. :D As for the algorithm, I got around not having an encoder by timing the amount it took for the horn to make one full revolution*. (the el cheapo servos only move at one speed) I take the total time it rotates and divide that by the amount of samples it took during that time for one sensor. I then multiply that number by 180 degrees to get the increment of the theta component for each sample. The end result is a set of polar coordinates for 360degrees around the robot. You could also just take a measurement every (rotation time)/180 for each sensor, which gives you a smaller array, but it's a bit easier to work with. I didn't really see too much difference. *the robot still moves the sensor past this time to make sure it reaches the maximum of its travel. The robot just waited a set delay when moving one direction before taking measurements (since only one side traveled too far on the little servos I have). Its a bit inaccurate, but it worked well enough to hug walls, avoid chair legs, and go through doors. Instructions print drill out holes if necessary screw onto servo horn bolt sensors on with m3 bolts robot Also, if anyone sees my other tank tread lying around let me know. My robot is a whole lot less exciting when it can only turn. :(