
Bill Of Material

Coding
Most TDS meters have an analogue pin that reads the analogue value and converts it into TDS reading in Parts Per Million (ppm). There are many TDS sensors for Arduino, which have different reference and analogue out voltages. Here, I have used a sensor having an output between 0 V – 2.3 V for the measurement of TDS value. TDS meter manufacturing companies implement a code in their devices that contains a formula for converting the output (voltage) into ppm. You simply need to get that code, modify and include it in your code, which will allow you to update the TDS value of water on the OLED display in real-time. Next, install the U8g2 library for interfacing with the SSD 1306 display.
Fig 2.

Fig 3.
Connection

Fig 4.Connection
Testing
Put the sensor in water samples from lakes, ponds, taps and RO filters to monitor and test the TDS in real-time.
Fig 5.Testing prototype

Fig 6.Showing TDS value