TDS Sensor Application in Laser Communication for Automatic Water Monitoring Systems

TDS automatic data collection was designed based on a sensor and Arduino board using red laser beam communication. The sensor was calibrated by measuring 4 different water solutions using a commercial TDS Meter compared with the TDS sensor output. The calibrated sensor was then tested in laser communication where the data processed by first Arduino was modulated by red laser frequency through pulse-width-modulation (PWM) schemes. The modulated signal was sent via a laser beam where solar cell captured it as a photodetector in the receiver. The received data was demodulated inside the second Arduino to be displayed in a serial monitor for communication performance observation. As the result, the link distance of TDS data transmission can reach 25 m and 4 m in free-space and water medium, respectively. When the transmission channel was a water environment, the link distance will be depended on PWM types utilized in the experiment.