Issue with "SparkFun Auto pHAT for Raspberry Pi" and "Hobby Motor with Encoder - Metal Gear" (ROB-16328 and ROB-16413)

Robotics
1

Dear Customer Service Team,

I am writing to report an issue with the “SparkFun Auto pHAT for Raspberry Pi” (ROB-16328) in combination with the “Hobby Motor with Encoder - Metal Gear” (ROB-16413).

  • The pHAT is powered via USB-C.
  • I have used three of the motors so far.
  • Each motor has stopped delivering encoder signals after some time (I suspect a defect in the Hall sensors).
  • The motors themselves are still operational.
  • I have checked the wiring and the encoder inputs on the pHAT, and these appear to be working correctly.

I would appreciate your guidance on the following points:

  1. What is the most likely cause of this issue? Is it a problem with the motor quality or the pHAT?
  2. Is there anything further I can do to isolate the issue or troubleshoot the problem?
  3. Are there any alternative motors that you would recommend as replacements for these ones?
  4. Is there a way to reactivate the encoders if they have been deactivated?

I look forward to your assistance and thank you in advance for your help.

Best regards,
Ed

2
  1. What code are you using? The demo for the encoders SparkFun Auto pHAT Hookup Guide - SparkFun Learn will report up to 37267 ticks; I presume you’re not just over-running that?

Can you measure the output or current of the encoder wires/circuit to see if they are producing anything?

  1. Be sure to use a regulated power supply when powering…fluctuating power delivery might be causing bad surges in the encoders’ circuitry

  2. Eh, we don’t have much but we sell these too Hobby Motor with Encoder - Plastic Gear (Pair, Red) - ROB-24053 - SparkFun Electronics but they appear to be nearly identical; we also have regular encoder kits Wheel Encoder Kit - ROB-12629 - SparkFun Electronics you could add to a project, and also as a kit

  3. See above about measuring them while in-use to see if they are generating any signal…but I’m guessing they aren’t :-/

3
  1. I am using the demo… for the functional motor i get increasing/decreasing counts when I turn the wheel manually. For the broken one I get “0” for both directions. I`ve also used own code snippets for reading out encoder values… same result.
  2. Ì’m using this one: https://www.waveshare.com/ups-hat-d.htm to power the pHat via USB-C.
  3. Not really a solution…
    Either I am doing something wrong
    → then I would really like to know how to improve…
    or there is an issue with the motors/encoders (or maybe with the pHat)
    → then it`s a topic for your QC department…
  4. I measured the voltage for outputs A/B… the functional motor alternates between 0.0 V and 3.3 V on A, resp. B when I turn the wheel by hand. One of the broken motors shows constant 3.3 V on A independent of wheel movement. The other one alternates between 0.88 V and 0.93 V when the wheel is turned.

Thanks for your support!