Micro Bot Sensor Not Calibrating

Hello!

I am using the microbot kit with some students for a STEM challenge. We are trying the staying in the box and follow the line experiment and can not get the sensor to calibrate to different colours of surfaces. The range is only between 830 and 835 and doesn’t change much if we test with different colours like black, white and painter tape. We are using the code in the Experiment.

https://learn.sparkfun.com/tutorials/mi … g-in-a-box

We would like the bot to go through a maze that is made with green painter’s tape.

Thank you for your help.

What does it read if you fully block light to the sensor, and what does it read if you shine light at it?