SparkFun OTOS returning incorrect distance values despite calibration attempts

Hello, our FTC team has been working with the SparkFun OTOS sensor, but we are consistently seeing incorrect distance readings.

What we’ve tried/our setup:

  • We have run both the unmodified sample OpMode and our own code (both show the same issue).
  • We use clean and flat FTC standard AndyMark tiles (new this year).
  • The sensor is mounted at the exact center of the robot, 10mm above the field tiles.
  • We have removed the Kapton tape, and the sensor lens is clean.
  • The testing environment is a consistent temperature.
  • We have tried adjusting the linear scalar.
  • We have adjusted the angular scalar (heading drift is now minimal, ~1e-11 °/sec).

Problem:
The OTOS consistently reports incorrect distance values.

  • The error isn’t uniform between X and Y.
  • From test to test the amount of inconsistency varies.
  • It increases as the robot moves, but not at a consistent rate (sometimes growing faster in X, sometimes in Y).
  • OTOS especially struggles when multiple waypoints are used Adjustment of the scalar
  • It’s not necessarily a growing error from one waypoint to another. It’s more of an error that may become larger or smaller from one waypoint to the next.

Questions:

  • Is there a way to adjust the X and Y scalars independently?
  • Has anyone else seen this issue on AndyMark FTC tiles, and if so how did you correct it?
  • Could this be a hardware issue, or is further calibration needed?

Any advice would be greatly appreciated — thank you!