TDS (Total Dissolved Solids) is a measure of the combined total of organic and inorganic substances contained in water. It can be a general indicator of water quality. The unit of TDS measurement is ppm or milligrams per liter (mg/L). The larger the TDS value, the more dissolved substances in water.
In many consumer products, the TDS value is calculated by measuring the conductivity of water (in uS/cm), which is roughly 1 ppm TDS = 2uS/cm. Using parallel cylindrical electrodes with fixed distance as the measuring probe, the probe is placed in water and a voltage is applied between the two electrodes to measure the conductivity.
Factors affecting the accuracy of TDS measurement include water temperature, flow rate, etc. In general, the standard measurement temperature is 25°C. For each 1°C increment, the TDS value increases by about 2%. When measuring TDS, the water temperature is usually measured together for temperature compensation.
The Holtek TDS Workshop integrates the rich functions of TDS measurement, temperature measurement, button input, display, communication etc. You can complete the configurations and generate MCU codes in several steps. The TDS platform also has a calibration monitoring window to calibrate the device and monitor the measured TDS value continuously. The measurement records can be exported to an excel file.
Holtek provides six modules and the development board, ESK-TDS-100, that can work with the TDS platform. Each module includes a TDS sensor probe (TDS-37). The ESK-TDS-66F019 is a measurement module based on the MCU HT66F019.
The TDS modules support both single-channel and dual-channel measurements of TDS and temperature. But they do not support the LCD, LED, and button functions of the TDS Display Board (ESK-TDS-100). Either the UART or I2C can be used for communication.
Assembled dimension: 80 x 37 x 85 mm
Net weight: 8.5g (PCB)
1. TDS module ESK-TDS-66F019 x 1
2. TDS sensor probe (TDS-37) x 1