TDS Sensor not working
uwe.klie 2026-01-16 23:00:47 181 Views2 Replies Hi,
I got the TDS analog sensor for the Arduino, but this one isn't working.
I have done some measurements with a Oszilloscope and something is strange.
The signal out from the LMV324 (A) towards the pobe pin2 is only between 200mV and 750mV, but it should be between -3V and +3V - right?
The output frequency from the CD4060BM is 2,5 kHz.
The operating voltage is +3,3V and -2,7V, but should be +-3V, right?
The analog output of the board is constant at ~300mV and incresing by 50mV only if the probe is in water.
Has anybody some hints, I asume the LMV324 isn't working.
Thanks
uwe
Dealing with TDS sensors on Arduino can be a bit of a headache sometimes! I’ve built a few hydroponics and water monitoring systems myself, and I've learned the hard way that these sensors are super sensitive to environmental factors…
If your readings are jumping around, a pro-tip from my experience: make sure you’re using Temperature Compensation. TDS values change significantly with water temperature, so if you don't have a DS18B20 (or similar) sensor feeding data to your code to adjust the results, the readings won't be reliable. also, I always recommend doing a multi-point calibration with a known solution rather than just relying on the default library values…
Are you getting inconsistent values or is it just not responding at all? I’ve probably run into the same issue before, so feel free to share your setup!
Oliver.Taylor Thanks for your hint with the temperature and I will take care about it.
But I think that my Hardware has a problem, because the analog output value is mor or less constant and only shifting by 50mV when the sensor is in water.
I will get a replacement today and will then test it again.
afterwards I will comew back
