Motor Encoders are all Red

The motor encoders on my team’s robot are all glowing red even though we have changed the wires, encoder order, firmware updates, cortex’s, and the encoders themselves. SOS . . . _ _ _ . . .

I’ve had this happen to me before; in addition to what you’ve done, try making sure the wires are facing the right way in the I2C ports and in the encoder lids themselves. Also check the encoder gears (painted white and black), we once had a gear that had the paint all stripped off. Had to get that replaced.
Hope this helped!

I don’t think it is the gear because it affects the entire system even if we change and test the encoders one by one, but I check it anyways… thank you

Had a student this year plug in all of the wires in reverse. It looks fine because there is a male and female in each of the encoders. A female end will fit nicely in the female port on the cortex, but it will never make a connection. That’s an hour of troubleshooting I’ll never get back.

Start with the one encoder that’s closest to the cortex; unplug the whole daisy chain after the first encoder. Try different things to get just that one encoder working correctly. Add encoders one at a time and get each one working correctly before you plug in the next one. Otherwise you really have no idea where your problem lies.

  • If you get to a point where things stop working, swap out the wire connecting that last encoder with a wire you know works.
  • If it still doesn’t work, connect that last encoder directly to the cortex (instead of via daisy chain) with an extension wire you know works.
    —> Still not working?
    —> You have a bad encoder.
  • Work your way step-wise through the entire daisy chain.

You’re really wandering blindly if you try to fix the entire system all at once.

This is usually where I have my students start as well. As soon as the first encoder is working I suggest they go straight from the cortex to each of the encoders individually to ensure each encode works in isolation, then have them go back and start adding them in order until all are working. The vast majority of the time it has been wiring issues that have caused the problems. At the beginning of this year one team did have a Cortex that would intermittently affect all encoders. They would all be green, but not not report valid values.

I am very much looking forward to V5 and not having to deal with some of these types of issues.