KY-033 Tracking sensor module
As long as the tracker is powered it continues to spin the stepper motor which means that if I forget to turn off the tracker before the tracker reaches its top position and the threaded rod reaches its end position, the gears can be damaged by the relatively strong stepper motor. To prevent this some type of security circuit was needed. I could have mounted a simple microswitch somewhere, but I had this sensor lying in a bargain box and wanted to see if I could use it.
This sensor uses IR light to detect if a light reflecting or absorbing area is in front of it. The sensitivity (minimum range) of the sensor can be adjusted by the trim potentiometer. The function of the sensor mounted in the tracker is this: When the top part of the tracker is low, the sensor’s IR light reflects in the wood surface and the output from the sensor connected to the Arduino reset pin is high. When the star tracker’s top part reaches a predetermined set height by the trim potentiometer on the KY-033, the output of the sensor connected to the Arduino reset pin goes low and stops the program in the Arduino Nano, which causes the stepper motor to stop .