Low Cost, Battery Powered, TDS Meter Using MCU and PSoC

This low-cost Total Dissolved Solids (TDS) meter measures water quality by evaluating the electrical conductivity of a water sample. The system centers around a PSoC microcontroller development board, which features flexible, configurable internal analog and digital blocks. Dual electrodes are submerged into the water sample to act as a conductivity sensor. Because dissolved ions in the water allow electrical current to flow between the dual electrodes, the conductivity changes proportionally with the concentration of dissolved solids. To measure this accurately without causing rapid electrode polarization, the circuit utilizes discrete passive components like resistors and capacitors configured into RC networks to condition the excitation and measurement signals. The PSoC microcontroller processes the resulting analog signals, converting the raw electrical measurements into a meaningful TDS value. Finally, the calculated water purity data is rendered directly onto an LCD or LED display module for easy real-time viewing. Powered by an internal battery, the entire architecture remains isolated from mains power, allowing safe portability for field measurements.

Water quality monitoring in residential, commercial, and industrial applications to assess drinking water purity and contaminant levels.