Ultrasonic flow rate sensor

Using Arduino Sensors
1

Hi All.

Im struggling to get my head around the correct sensors to use to build an ultrasonic flow rate sensor. The premise is simple enough - 2 sensors, at deg one upstream and 1 downstream.

Flow is detected by measuring the time taken from send-receive.

My first idea was to purchase a low cost range-finder, but they appear to be unable to detect anything nearer than 2cm. This possibly may mean they cant detect range, but can still detect flow so I will order and test some out.

However, does anyone have any comments or experience on using ultrasonics to detect flow? I want to go down that route as its non intrusive and portable. I appreciate hall-effect sensors may be much easier.

Thank you.

2

skunkworx:
I appreciate hall-effect sensors may be much easier.

You are dead right about that. They are also a lot cheaper. However, using ultrasonic flowmeters is commoin in the industrial world because they handle large quantities and incur essentially zero maintenance. You can take some comfort in that you only need one. Ultrasonics use the 4-20 output system, which is no problem with Arduino.