I am making a TDS (Total Dissolved Solids) sensor. It is based on an ESP32 microcontroller. The aim is to measure the water quality in the river.
It comprises two copper electrodes to measure water conductivity.
It uses reference resistors together with voltage measurements (using the ADCs of the ESP32) to measure the current through the water, and hence the TDS can be calculated.
Also including a temperature sensor (DS18B20) which works very well - only needs a few lines of code.
I have built the TDS sensor but not yet calibrated it.
It would be good to get some info about sending measurements to a website, similar to the air quality monitor project. I have access to a site at the river, and with WiFi router at about 100 metres from the river.
Good to see your prototype device at our Sunday session yesterday. I think you got some pointers about how to get the ESP32 to post results to a web-accessible database?