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.

bmp180 module
bmp180 module

 

Wiring and layout

Make the following connections

GND <-> GND

3V3 <-> VIN (or 3Vo)

P19 <-> SCL

P20 <-> SDA

Here is a layout drawn in fritzing

microbit and bmp180
microbit and bmp180

 

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

#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