Grove-TDS-Sensor

Products & Technology Raspberry Pi
3

Hi @jiachenglu,
thanks for your reply but that doesn’t answer my question.

I am using a calibrated TDS pen. The ppm of the liquid is 200 ppm. The tds pen measures 198 ppm, the grove sensor 314ppm.

tdsValue = (133.42/voltage*voltage*voltage-255.86*voltage*voltage+857.39*voltage)*0.5

If you google on this formula everyone (vendors) is using it but no one explains it. Can someone explain the static values? What does they mean?

There is no temperature correction and no calibration in this code. Without this the sensor/hardware is useless?