STEP EIGHT: Calibrate Line Sensor

Overview

In this lesson, you will learn how to calibrate your QTR-MD-01A Reflectance Sensor so that it will work reliably with your sumo robot.

Set Up

Mock up a test stand for your sensor.

  1. Connect your sensor to your breadboard via three long jumpwires.

  2. Set up your sensor with a multimeter. You can refer to the previous lesson if you need help.

  3. Using materials such as cardboard or chipboard, create a mount for your sensor that sets it about 5mm from the surface of your table. You may also want to shroud it from stray light.

  4. Create a test card which includes a black and white surface that best mimics the surface of the sumo ring. This can be done with an index card and tape, but note that not all white surfaces reflect eqaully and not all black surfaces reflect equally. Check out the surface of the sumo table as a reference.

  5. Place the white surface under the sensor and record voltage range in your notebook. It is likely you will not get just one voltage but a small range. Repeat this process for the black surface.

  6. Now connect the output from your sensor to an analog port on your microcontroller.

  7. Write a program to display these values on your serial monitor.

  8. Again, record the range of analog values in your notebook for both the white and black surfaces.

  9. Confirm you results with a teacher.