Technical reports: Liquid presence sensing

Flowing Water

At LAIIER we have carried out a series of tests for our Severn sensors to show their performance for a range of liquids and setups. Here we present a technical report that measures water streams over the Severn sensor.

Flowing water

Measuring the response of the Severn sensor to constant streams of tap water when mounted vertically. We wanted to test if slow flow rates could be detected and how readings varied as flow rates increased.


Setup of measuring water flow over the Severn sensor

The Severn sensor was mounted vertically and a 100 ml burette was positioned to dispense water over it. The burette was filled with 100 ml of tap water for each flow rate. The flow rate was varied by incrementally increasing the valve opening so each test had to be timed to calculate the final flow rate. 

The Severn sensor was connected to the Severn board in order for serial data to be collected. The burette valve was opened at five seconds. 

Results and findings

  • The lower flow rates of 0.38 ml/s could be detected with a strong drop in sensor reading.
  • As the flow rate increases, there is a larger decrease in reading.
  • As the 0.86 ml/s reading shows, the signal can vary slightly which can be due to how the stream of water flows on the sensor surface.
Graph showing the response of water streams over the Severn sensor


When the Severn sensor is mounted vertically, it can detect small streams of water from a flow rate of 0.38 ml/s. The sensor is able to detect larger flow rates with a stronger reading.