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3pi IR Sensors not working


Hi there,

I have a brand new 3pi Robot still running the demo program-- however the IR sensors do not seem to be working, or at least are not very sensitive. They are all full black bars when on a light surface, and running them under my finger or a black object has no effect.

However, pointing the IR sensors at a bright window causes them to go down. Help please!



I’m sorry you are having trouble with your new 3pi. It sounds like the IR emitters are not turning on. Can you post a clear picture of the front half of the underside of the 3pi? Can you also inspect the five reflectance sensors to make sure that the solder joints on their leads look good? We test all units before the ship, so it is likely the emitters were working at one point. Did the 3pi run into any walls or suffer any trauma that might have dislodged a component or cracked a solder joint?

- Ben


Here is a photo of the bottom-- you may not be able to see, PC2 and PC4 have some questionable looking solder joints.


Thanks for the picture. You’re right, I can’t see well enough to evaluate the quality of the solder joints, but I suggest you try to touch up anything that seems off and see if that gets things working. It really sounds like the only problem is with the emitter part of the circuit, so if you can get them to turn on, the 3pi will likely be back to full functionality. You might find it helpful to look at the emitters using the display of a cheap digital camera, such as those commonly found on cell phones. If the camera lacks IR filters, you will be able to see the emitters glowing purple when then are on.

If you want to troubleshoot the problem even further, please see this post I made in a similar thread:

It has some useful diagrams along with a list of things you can check to try to narrow down the source of the problem.

- Ben