micro:bit and bmp180 sensor example

This bmp180 from Bosch is the best low-cost sensing solution for measuring barometric pressure and temperature. The sensor is soldered onto a PCB with a 3.3V regulator, I2C level shifter and pull-up resistors on the I2C pins. The BMP180 replaces the BMP085.

Specification

• Pressure sensing range: 300-1100 hPa (9000m to -500m above sea level)
• Up to 0.03hPa / 0.25m resolution
• -40 to +85°C operational range, +-2°C temperature accuracy

Here is a breakout which makes it easy to use the sensor, link at the bottom.

Wiring and layout

Make the following connections

GND <-> GND

3V3 <-> VIN (or 3Vo)

P19 <-> SCL

P20 <-> SDA

Here is a layout drawn in fritzing

Code

You will need the Adafruit BMP085 library for this example, you can either download it or use the library manager in newer Arduino IDEs.

https://github.com/adafruit/Adafruit-BMP085-Library

In this example I am only looking at the temperature and pressure but there are other functions in the library

Source code

#include <Wire.h>
#include <Adafruit_BMP085.h>
 
Adafruit_BMP085 bmp;
 
void setup() 
{
  Serial.begin(9600);
  if (!bmp.begin()) 
  {
    Serial.println("Could not find BMP180 or BMP085 sensor at 0x77");
    while (1) {}
  }
}
 
void loop() 
{
  Serial.print("Temperature = ");
  Serial.print(bmp.readTemperature());
  Serial.println(" Celsius");
 
  Serial.print("Pressure = ");
  Serial.print(bmp.readPressure());
  Serial.println(" Pascal");
 
 
  Serial.println();
  delay(5000);
}

Output

Open the Serial monitor and you should see something like this

Temperature = 20.10 Celsius
Pressure = 100775 Pascal

Temperature = 20.00 Celsius
Pressure = 100773 Pascal

Temperature = 19.90 Celsius
Pressure = 100778 Pascal

Temperature = 25.80 Celsius
Pressure = 100835 Pascal

Links

Free Shipping 1PC BMP180 Digital Barometric Pressure Sensor Board Module compatible with BMP085 For Arduino