How to Use Bar02 Pressure/Depth Sensor: Examples, Pinouts, and Specs

The Bar02 Pressure/Depth Sensor from Blue Robotics is a high-precision sensor designed to measure the pressure of the environment around it, which can be used to calculate depth when submerged in a liquid, typically water. It is ideal for a wide range of applications, including oceanographic research, water level monitoring, and underwater vehicle depth determination.

• Underwater robotics and ROVs (Remotely Operated Vehicles)
• Water level monitoring in tanks and reservoirs
• Diving computers and depth gauges
• Environmental monitoring and oceanographic research
• Weather stations for barometric pressure readings

• Operating Voltage: 3.3V to 5V
• Pressure Range: 0 to 10 bar (0 to 145 psi)
• Depth Range: 0 to 100 meters (0 to 328 feet) in water
• Operating Temperature: -40°C to +85°C
• Accuracy: ± 0.1% FS (Full Scale)
• Resolution: 0.2 mbar (0.02 kPa)
• Output: I2C digital interface

1. Power Supply: Connect the VCC pin to a 3.3V or 5V power supply from your microcontroller or power management board.
2. Data Lines: Connect the SDA and SCL pins to the corresponding I2C data and clock lines on your microcontroller.
3. Ground: Connect the GND pin to the ground of your system.

• Ensure that the power supply is within the specified voltage range to prevent damage.
• Use pull-up resistors on the I2C data lines if they are not already present on your microcontroller board.
• Keep the sensor away from direct sunlight and sources of heat to maintain accuracy.
• When used underwater, ensure that the sensor's housing is properly sealed against water ingress.
• Calibrate the sensor if necessary, especially for precise depth measurements.

#include <Wire.h>

// Bar02 I2C address (check datasheet for your sensor's address)
const byte sensorAddress = 0x76;

void setup() {
  Wire.begin(); // Initialize I2C
  Serial.begin(9600); // Start serial communication at 9600 baud
}

void loop() {
  Wire.beginTransmission(sensorAddress);
  // Request 3 bytes from the sensor
  Wire.requestFrom(sensorAddress, 3);
  if (Wire.available() == 3) {
    // Read the bytes if available
    byte highByte = Wire.read();
    byte midByte = Wire.read();
    byte lowByte = Wire.read();
    
    // Combine the bytes into a 24-bit number
    long pressure_raw = (long)highByte << 16 | (long)midByte << 8 | lowByte;
    
    // Convert the raw value to pressure in mbar
    double pressure_mbar = pressure_raw / 4096.0;
    
    // Print the pressure value to the serial monitor
    Serial.print("Pressure: ");
    Serial.print(pressure_mbar);
    Serial.println(" mbar");
  }
  Wire.endTransmission();
  
  delay(1000); // Wait for a second before reading again
}

• Inaccurate Readings: Ensure the sensor is calibrated and not exposed to rapid temperature changes.
• No Data on I2C: Check the wiring, ensure pull-up resistors are in place, and verify that the correct I2C address is being used.
• Sensor Not Responding: Make sure the sensor is powered with the correct voltage and the ground is properly connected.

• Calibration: Follow the manufacturer's instructions for calibration to ensure accuracy.
• Wiring Check: Double-check all connections and solder joints for reliability.
• Pull-Up Resistors: If data is not being received, add 4.7kΩ pull-up resistors to the SDA and SCL lines.
• I2C Scanning: Use an I2C scanner sketch to confirm the sensor's address and connectivity.

Q: Can the Bar02 sensor be used in saltwater? A: Yes, but ensure that the sensor's housing is appropriate for saltwater use to prevent corrosion.

Q: What is the maximum depth the Bar02 sensor can measure? A: The sensor can measure depths up to 100 meters (328 feet) in water.

Q: How do I convert pressure readings to depth? A: Depth in meters can be approximated by dividing the pressure in mbar by 100 (assuming freshwater and standard gravity).

Q: Is the sensor temperature compensated? A: Yes, the Bar02 sensor includes temperature compensation for accurate readings over its operating temperature range.