micro:bit and MPL3115A2 absolute pressure sensor example
The MPL3115A2 is a compact, piezoresistive, absolute pressure sensor with an I2C digital interface. MPL3115A2 has a wide operating range of 20 kPa to 110 kPa, a range that covers all surface elevations on earth. The MEMS is temperature compensated utilizing an on-chip temperature sensor. The pressure and temperature data is fed into a high resolution ADC to provide fully compensated and digitized outputs for pressure in Pascals and temperature in °C.
The compensated pressure output can then be converted to altitude, utilizing the formula stated in Section 9.1.3 “Pressure/altitude” provided in meters.The internal processing in MPL3115A2 removes compensation and unit conversion load from the system MCU, simplifying system design
Parts List
Quantity | Link |
1 | MPL3115A2 I2C Intelligent Temperature Pressure Altitude Sensor V2.0 for Arduino |
1 | BBC micro:bit bulk micro-controller with motion detection, compass, LED display and Bluetooth |
Schematics/Layout
Code
Again we use a library –https://github.com/adafruit/Adafruit_MPL3115A2_Library
[codesyntax lang=”cpp”]
#include <Wire.h> #include <Adafruit_MPL3115A2.h> // Power by connecting Vin to 3-5V, GND to GND // Uses I2C - connect SCL to the SCL pin, SDA to SDA pin // See the Wire tutorial for pinouts for each Arduino // http://arduino.cc/en/reference/wire Adafruit_MPL3115A2 baro = Adafruit_MPL3115A2(); void setup() { Serial.begin(9600); Serial.println("Adafruit_MPL3115A2 test!"); } void loop() { if (! baro.begin()) { Serial.println("Couldnt find sensor"); return; float pascals = baro.getPressure(); // Our weather page presents pressure in Inches (Hg) // Use http://www.onlineconversion.com/pressure.htm for other units Serial.print(pascals/3377); Serial.println(" Inches (Hg)"); float altm = baro.getAltitude(); Serial.print(altm); Serial.println(" meters"); float tempC = baro.getTemperature(); Serial.print(tempC); Serial.println("*C"); delay(250); } }
[/codesyntax]
Output
Open the serial monito
Adafruit_MPL3115A2 test!
30.17 Inches (Hg)
-48.25 meters
35.75*C
30.17 Inches (Hg)
-47.81 meters
35.63*C
30.17 Inches (Hg)
-48.00 meters
35.56*C
30.17 Inches (Hg)
-47.81 meters
35.44*C
Links
https://www.nxp.com/docs/en/data-sheet/MPL3115A2.pdf
MPL3115A2 I2C Intelligent Temperature Pressure Altitude Sensor V2.0 for Arduino