How to Use tds probe: Examples, Pinouts, and Specs

A TDS (Total Dissolved Solids) probe is a sensor used to measure the concentration of dissolved solids in a liquid, typically water. It is commonly used in water quality testing, aquariums, hydroponics, and various industrial applications. The TDS value is an important parameter for assessing the purity of water and ensuring it meets specific standards for various uses.

1. Power Supply: Connect the VCC pin to a 3.3V or 5V power supply.
2. Ground: Connect the GND pin to the ground of the power supply.
3. Analog Output: Connect the AOUT pin to an analog input pin on a microcontroller (e.g., Arduino).

  +-------------------+
  |                   |
  |   TDS Probe       |
  |                   |
  |   +-----+-----+   |
  |   | VCC | GND |   |
  |   +-----+-----+   |
  |       |     |     |
  |       |     |     |
  +-------|-----|-----+
          |     |
         5V    GND
          |     |
          |     |
  +-------|-----|-----+
  |       |     |     |
  |     Arduino UNO   |
  |                   |
  |   +-----+-----+   |
  |   | A0  | GND |   |
  |   +-----+-----+   |
  |       |           |
  |       |           |
  +-------|-----------+
          |
         AOUT

• Calibration: Regularly calibrate the TDS probe using a standard solution to ensure accurate readings.
• Temperature Compensation: TDS readings can be affected by temperature. Use a temperature sensor for compensation if high accuracy is required.
• Cleaning: Keep the probe clean to avoid contamination and ensure accurate measurements. Rinse with distilled water after each use.
• Avoid Air Bubbles: Ensure there are no air bubbles on the probe surface during measurement, as this can affect the readings.

// TDS Probe Example Code for Arduino UNO

const int TDS_PIN = A0; // Analog pin connected to TDS probe
float voltage, tdsValue;

void setup() {
  Serial.begin(9600); // Initialize serial communication
}

void loop() {
  int sensorValue = analogRead(TDS_PIN); // Read analog value from TDS probe
  voltage = sensorValue * (5.0 / 1023.0); // Convert analog value to voltage
  tdsValue = (133.42 * voltage * voltage * voltage - 255.86 * voltage * voltage 
              + 857.39 * voltage) * 0.5; // Convert voltage to TDS value (ppm)
  
  Serial.print("TDS Value: ");
  Serial.print(tdsValue);
  Serial.println(" ppm");
  
  delay(1000); // Wait for 1 second before next reading
}

1. Inaccurate Readings:

   • Solution: Ensure the probe is calibrated correctly. Check for any contamination or air bubbles on the probe surface.

2. No Output Signal:

   • Solution: Verify the connections. Ensure the power supply voltage is within the specified range (3.3V - 5V).

3. Fluctuating Readings:

   • Solution: Stabilize the liquid sample. Ensure the probe is fully submerged and there are no air bubbles.

Q1: How often should I calibrate the TDS probe?

• A1: It is recommended to calibrate the TDS probe at least once a month or whenever you notice inconsistent readings.

Q2: Can I use the TDS probe in hot water?

• A2: The TDS probe is designed to operate within a temperature range of 0°C to 60°C. Using it in hotter water may damage the probe or affect accuracy.

Q3: How do I clean the TDS probe?

• A3: Rinse the probe with distilled water after each use. For thorough cleaning, use a soft brush and mild detergent, then rinse with distilled water.

By following this documentation, users can effectively utilize the TDS probe for accurate water quality measurements in various applications.