A TDS (Total Dissolved Solids) sensor measures the concentration of dissolved solids in a liquid, typically expressed in parts per million (ppm). It is widely used in water quality monitoring, aquariums, hydroponics, and water treatment systems to ensure the liquid's purity and suitability for specific applications. By detecting the electrical conductivity of the liquid, the sensor estimates the total dissolved solids present.
This circuit is an environmental monitoring system using an ESP32 microcontroller to collect data from various sensors, including temperature, humidity, air quality, pH, and TDS sensors. The collected data is displayed on an OLED screen, sent to ThingSpeak for remote monitoring, and email alerts are sent if critical thresholds are exceeded.
Open Project in Cirkit Designer
This circuit connects a TDS (Total Dissolved Solids) sensor to an ESP32 microcontroller. The TDS sensor's power is supplied by the ESP32's 3.3V and ground pins, and its analog output is connected to GPIO 35 of the ESP32 for measurement. The purpose of this circuit is to enable the ESP32 to read the TDS level of a solution, which is commonly used in water quality testing.
Open Project in Cirkit Designer
This circuit is a water quality monitoring system that uses an ESP32 microcontroller to measure TDS, pH, temperature, and turbidity of water. The system includes sensors for each parameter and a start switch, with data being displayed on a 16x2 I2C LCD and logged via serial communication.
Open Project in Cirkit Designer
This circuit is a water quality monitoring system using an Arduino Uno, which reads TDS values from a TDS sensor and displays the results on a 16x2 I2C LCD. A green LED indicates good water quality, while a SIM900A module sends an SMS alert if the water quality is poor.
Open Project in Cirkit DesignerBelow are the key technical details of a typical TDS sensor module:
| Parameter | Value |
|---|---|
| Operating Voltage | 3.3V - 5V DC |
| Operating Current | 10mA (typical) |
| Measurement Range | 0 - 1000 ppm |
| Accuracy | ±10% (25°C calibration) |
| Output Signal | Analog voltage (0 - 2.3V) |
| Temperature Compensation | Supported (via external circuitry) |
| Probe Material | Stainless steel |
| Cable Length | ~1 meter |
| Operating Temperature | 0°C - 60°C |
The TDS sensor module typically has three pins for connection:
| Pin | Name | Description |
|---|---|---|
| 1 | VCC | Power supply input (3.3V - 5V DC) |
| 2 | GND | Ground connection |
| 3 | AOUT | Analog output signal proportional to the TDS value |
Connect the Sensor Module:
VCC pin to the 5V or 3.3V power supply of your microcontroller.GND pin to the ground of your circuit.AOUT pin to an analog input pin of your microcontroller (e.g., Arduino).Calibrate the Sensor:
Place the Probe:
Read the Output:
AOUT pin.Below is an example of how to use a TDS sensor with an Arduino UNO:
// Define the analog pin connected to the TDS sensor
const int tdsPin = A0; // Analog pin A0 is used for the sensor's output
const float vRef = 5.0; // Reference voltage of the Arduino (5V for UNO)
const int adcResolution = 1024; // ADC resolution (10-bit for Arduino UNO)
void setup() {
Serial.begin(9600); // Initialize serial communication at 9600 baud
}
void loop() {
int sensorValue = analogRead(tdsPin); // Read the analog value from the sensor
float voltage = (sensorValue / float(adcResolution)) * vRef;
// Convert ADC value to voltage
float tdsValue = (voltage / 2.3) * 1000;
// Convert voltage to TDS value (assuming 0-2.3V maps to 0-1000 ppm)
Serial.print("TDS Value: ");
Serial.print(tdsValue);
Serial.println(" ppm"); // Print the TDS value in ppm
delay(1000); // Wait for 1 second before the next reading
}
Inaccurate Readings:
No Output Signal:
Fluctuating Readings:
Temperature Dependency:
Q: Can the TDS sensor measure salinity?
A: While the TDS sensor is not specifically designed for salinity, it can provide an approximate measurement since salinity contributes to the total dissolved solids.
Q: How often should I calibrate the sensor?
A: Calibration is recommended every few weeks or whenever the sensor is used in a new liquid.
Q: Can I use the TDS sensor in hot liquids?
A: The sensor is rated for temperatures up to 60°C. Avoid using it in liquids above this temperature to prevent damage.
Q: Is the TDS sensor suitable for measuring pure water?
A: Pure water has very low TDS levels, which may be below the sensor's detection range. It is better suited for measuring water with dissolved solids.