In this project we will get the current altitude and temperature using an MPL3115A2 pressure sensor connected to an LCD keypad shield fitted to an Arduino Uno
Here is a little information regarding the sensor.
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
I used the following parts for this project
Schematics/Layout
lcd shield and MPL3115A2 layout
Code
We need to add a library via the library manager or download it from – https://github.com/adafruit/Adafruit_MPL3115A2_Library
#include <Wire.h>
#include <LiquidCrystal.h>
#include <Adafruit_MPL3115A2.h>
//setup for the LCD keypad shield
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);
Adafruit_MPL3115A2 baro = Adafruit_MPL3115A2();
void setup()
{
//init serial for some debug
Serial.begin(9600);
Serial.println("Adafruit_MPL3115A2 test!");
//init LCD
lcd.begin(16,2);
//line 1 - temperature
lcd.setCursor(0,0);
lcd.print("ALTITUDE");
//line 2 - humidity
lcd.setCursor(0,1);
lcd.print("TEMPERATURE");
}
void loop()
{
if (! baro.begin())
{
Serial.println("Couldnt find sensor");
return;
}
float pascals = baro.getPressure();
float altm = baro.getAltitude();
float tempC = baro.getTemperature();
//display readings on lcd
lcd.setCursor(0,0);
lcd.print("Alt = ");
lcd.print(altm);
lcd.print(" m");
lcd.setCursor(0,1);
lcd.print("Temp = ");
lcd.print(tempC);
lcd.print(" *c");
delay(500);
}
Output
Here is a video showing my results, you should get similar results on your LCD
Links
https://www.nxp.com/docs/en/data-sheet/MPL3115A2.pdf