The flow sensor (YF S201) is used to measure the flow of a liquid or gas.

When water or air passes through the flow sensor, the blades of a fan inside the sensor turn. As they turn, they generate electricity.


  1. Water Meter: sensor measures the volume or flow rate of water at a tap to alert when there is too much water being used.
  2. Lung Capacity Meter: sensor measures how much air a person can blow out to determine their lung capacity.
  3. Shower Flow Monitor: sensor measures how much water is being used to alert when there is excess usage.




  1. Connect the flow sensor to the tap - rotate it until it is tight enough. Use FTA (female threaded adapter/Threaded Collars to fix the sensor to the pipes.
  2. Tighten the FTA using a spanner and use the teflon tape to prevent any leakages that might happen.