Introduction

Clean and safe water is a fundamental requirement for human health, agriculture, industry, and ecosystems. However, water sources are increasingly affected by pollutants due to urbanization, industrialization, and agricultural activities. Traditional laboratory-based water testing methods are time-intensive, require manual sampling, and lack real-time capabilities.
To address these challenges, this project presents a Smart Water Quality Monitoring System using Raspberry Pi, which is capable of continuously monitoring vital water parameters such as pH level, turbidity (clarity), temperature, and Total Dissolved Solids (TDS). By integrating sensors with a Raspberry Pi microcontroller and using digital displays and connectivity features, this system enables real-time, remote, and automated monitoring of water quality. The system is especially suitable for water treatment plants, rivers, reservoirs, and aquaculture where continuous monitoring is crucial.

Working Principle

The core principle of the system lies in sensing and digitizing physical and chemical characteristics of water using electronic sensors. Each sensor measures a specific parameter:

• The pH sensor provides a voltage that varies according to the hydrogen ion concentration in water.

• The turbidity sensor uses infrared light scattering to measure the amount of suspended particles.

• The TDS sensor determines electrical conductivity which correlates to dissolved solids in water.

• The temperature sensor (DS18B20) provides digital temperature readings.

These sensors (except the digital temperature sensor) typically output analog signals. As the Raspberry Pi lacks an analog-to-digital interface, the MCP3008 ADC is used to convert analog signals to digital. The Raspberry Pi reads these digital values via SPI, processes the data, and displays it on an I2C LCD. The system can also log and transmit this data for further analysis or alert generation.

Methodology

1. Sensor Deployment: Sensors are submerged or exposed to a water sample in a controlled container. Their outputs are calibrated based on reference conditions.

2. Data Acquisition:

   • Analog sensors (pH, turbidity, TDS) are connected to an MCP3008 ADC.

   • The DS18B20 temperature sensor is connected to a GPIO pin for 1-Wire digital communication.

3. Signal Processing:

   • ADC data is read using the Raspberry Pi’s SPI interface.

   • Sensor data is converted into standard units (e.g., pH scale, NTU for turbidity, °C for temperature, ppm for TDS).

4. Display and Monitoring:

   • Real-time data is shown on a 16x2 or 20x4 I2C LCD display.

   • The system may log data to a local file or transmit to a cloud platform (if networked).

5. Threshold and Alerts:

   • The system can compare readings to predefined safe thresholds.

   • In case of critical deviation, alerts or warnings can be triggered via buzzer/display/logging.

Components Used