IoT water tank telemetry project – JSN-SR04T-3.0 – first trial

IoT water tank telemetry project – HC-SR04 – first trial mentioned an inexpensive ultrasonic ranging sensor for trial.

Above is the JSN-SR04T-3.0, a waterproof transducer on a cable and the electronics board. The protocol is HC-SR04 PWM. No specifications or datasheet were found (other than the seller's brief description).

A short trial was conducted with range fixed at 2.3m. Occasionally the measurements were wild.

Above is the plotted simulated dam volume, occasional spikes that are grossly in error.


Above is an example set of eight successive pulse width measurements sorted ascending. There is a huge spread and not even the median would be a good estimator.

Nevertheless, zooming in on the data we can see that the temperature compensation scheme is working.

The sensor did not respond proportionately to range for range less than about 0.25m.

This is one to dismiss as unsuitable.

A work in progress…