Lots of strange Sharp IR Noise…?
August 11, 2011
Hey everyone. So, I just finished my first robot in a few years, my first being 2 1/2 years ago. This one is a lot more complicated in terms of hardware since I made my own boards and all, and have 5 ICs in one circuit. I'm done with programming and everything runs well but there's one ongoing problem with my Sharp IR GP2D120 sensor.
Now, there's nothing physically wrong with the sensor. When connecting to an empty Picaxe project board and debugging the adc value, it acts normally. However, when used in my circuit, when only reading the adc values from the sensor, it gives back a constant reading of 60 - 90 even if nothing is in front of the sensor!! I tried putting a 10 uF electrolytic and .1 uF non-elec. between GND and VCC right on the sensor, but it only brought the maximum false reading down from 100. This is a huge problem, since it reduces the maximum distance into about 1/3 - 1/4 of the normal. As in, when I have the sensor pointed at the ceiling even with the lights off, it gives a reading of ~ 60. As such, it has greatly reduced my robot functionality. As I've said, by itself in an otherwise empty circuit, it works great, so it's not the sensor completely to blame. Sorry on not having a schematic, I'll try to post one....