JSN-SR04T-3.0 Ultrasonic - Please note

[zboblamont]

Having decided to have another go at ultrasonics for level in the underground bulk water tank (this time in plastic tube not steel - Condensation issues below -5c), I ordered up a pair of sensors, which on arrival turned out to be version 3.0.

Looking up the differences, they state 5v so no longer specced as 3v, trigger exceeding 10 microseconds, and the blind spot had increased from 20cm to 23 over V2.0.
Curious whether 5v would restore readings on the original V2.0, was surprised to see it responding accurately again.

Once installed in plastic in the tank, an error was evident but only for near objects.
eg - At 1300mm physical depth to surface the reading near enough correlated, but with the tank full and surface 295mm below the transducer it reads 273, as the level falls to 330 it reads 309 etc., etc..
I bench tested the second set and got the exact same error on short range.

A correction factor will solve my own use case, or perhaps even refit a V2.0, but for any looking to deploy these new V3.0 types it is worth checking short range accuracy.