In industry the exact position of the metal tool in CNC or Lathe machines or the robotic arms in automated systems is very important and essential to ensure your program is working correctly. Also counting the number of parts on a production belt is necessary to keep the data logged. This Ky-036 Metal Touch Sensor Module is a low cost solution of the above mentioned problems. It has a LM393 Comparator IC onboard which will provide Digital Output to be connected to GPIO Pins to your microcontroller. It also has resistive potentiometer to change the sensitivity of the output to touch. It also has M2 sized bolt holes for easy installation.
As this is a 5V Module, You need to connect VCC Pin to 5V Supply and You can take the Digital Output from DO Pin and connect it to any GPIO Pin on your controller. The module will give output High when touch is detected and Low otherwise.
(Note: Product Image are shown for illustrative purposes only and may different from the actual product)