How to Use 0-40kpa TM711 pressure sensor: Examples, Pinouts, and Specs

The 0-40kPa TM711 pressure sensor, manufactured by ZyrexRobotics (Part ID: Pressure Sensor), is a highly sensitive device designed to measure low-pressure ranges from 0 to 40 kPa. This sensor is ideal for applications requiring precise pressure monitoring, such as HVAC systems, weather stations, and industrial automation. Its compact design and reliable performance make it a popular choice for both hobbyists and professionals.

• HVAC systems for monitoring air pressure
• Weather stations for atmospheric pressure measurement
• Industrial automation for pressure control and monitoring
• Medical devices requiring low-pressure sensing
• Educational projects and prototyping

The following table outlines the key technical details of the 0-40kPa TM711 pressure sensor:

The TM711 pressure sensor has a 3-pin interface. The pinout is as follows:

To use the TM711 pressure sensor in a circuit:

1. Connect the VCC pin to a 3.3V or 5V power supply.
2. Connect the GND pin to the ground of your circuit.
3. Connect the OUT pin to an analog input pin of your microcontroller or ADC (Analog-to-Digital Converter).

• Ensure the supply voltage is within the specified range (3.3V to 5V) to avoid damaging the sensor.
• Use a stable power source to minimize noise in the output signal.
• Avoid exposing the sensor to pressures beyond its rated range (40 kPa) to prevent permanent damage.
• If using the sensor in a noisy environment, consider adding a capacitor (e.g., 0.1 µF) between the VCC and GND pins to filter out noise.

Below is an example of how to interface the TM711 pressure sensor with an Arduino UNO to read and display pressure values:

// TM711 Pressure Sensor Example with Arduino UNO
// Reads the analog output from the sensor and converts it to pressure (kPa)

const int sensorPin = A0; // Connect the OUT pin of the sensor to A0
const float sensorMinVoltage = 0.5; // Minimum output voltage (V) at 0 kPa
const float sensorMaxVoltage = 4.5; // Maximum output voltage (V) at 40 kPa
const float pressureRange = 40.0;   // Pressure range of the sensor (kPa)

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

void loop() {
  int sensorValue = analogRead(sensorPin); // Read the analog value (0-1023)
  float voltage = sensorValue * (5.0 / 1023.0); // Convert to voltage (0-5V)
  
  // Calculate pressure in kPa based on sensor output
  float pressure = (voltage - sensorMinVoltage) * (pressureRange / 
                    (sensorMaxVoltage - sensorMinVoltage));
  
  // Ensure pressure is within valid range
  if (pressure < 0) pressure = 0;
  if (pressure > pressureRange) pressure = pressureRange;

  // Print the pressure value to the Serial Monitor
  Serial.print("Pressure: ");
  Serial.print(pressure);
  Serial.println(" kPa");

  delay(500); // Wait for 500 ms before the next reading
}

• The above code assumes a 5V Arduino UNO. If using a 3.3V microcontroller, adjust the voltage calculations accordingly.
• Use the Serial Monitor in the Arduino IDE to view the pressure readings.

1. No Output Signal

   • Ensure the sensor is powered correctly (check VCC and GND connections).
   • Verify that the analog output pin (OUT) is connected to the correct input pin on your microcontroller.

2. Inaccurate Readings

   • Check for noise in the power supply and add a decoupling capacitor if necessary.
   • Ensure the sensor is not exposed to pressures outside its specified range.
   • Verify the calibration values in your code (e.g., sensorMinVoltage and sensorMaxVoltage).

3. Fluctuating Output

   • Ensure stable power supply voltage.
   • Check for loose or poor connections in the circuit.

Q: Can the TM711 measure negative pressure?
A: No, the TM711 is designed to measure pressures in the range of 0 to 40 kPa only.

Q: Can I use the TM711 with a 3.3V microcontroller?
A: Yes, the TM711 operates with a supply voltage of 3.3V to 5V. Ensure the output signal is within the ADC range of your microcontroller.

Q: How do I protect the sensor from overpressure?
A: Use a pressure relief valve or a mechanical limiter to prevent the sensor from being exposed to pressures beyond 40 kPa.

Q: Is the sensor waterproof?
A: No, the TM711 is not waterproof. Avoid exposing it to liquids or high humidity environments.

By following the guidelines and best practices outlined in this documentation, you can effectively integrate the 0-40kPa TM711 pressure sensor into your projects for reliable and accurate pressure measurements.