Microbit and LPS22HB absolute pressure sensor example
In this article we look at another pressure sensor – this time its the LPS22HB piezoresistive absolute pressure sensor and we will connect it to our Microbit
This is the sensor I used
Here is some technical information about this sensor
The LPS22HB is an ultra-compact piezoresistive absolute pressure sensor which functions as a digital output barometer. The device comprises a sensing element and an IC interface which communicates through I2C or SPI from the sensing element to the application.
The sensing element, which detects absolute pressure, consists of a suspended membrane manufactured using a dedicated process developed by ST.
The LPS22HB is available in a full-mold, holed LGA package (HLGA). It is guaranteed to operate over a temperature range extending from -40 °C to +85 °C. The package is holed to allow external pressure to reach the sensing element.
Features
- 260 to 1260 hPa absolute pressure range
- Current consumption down to 3 μA
- High overpressure capability: 20x full-scale
- Embedded temperature compensation
- 24-bit pressure data output
- 16-bit temperature data output
- ODR from 1 Hz to 75 Hz
- SPI and I²C interfaces
- Embedded FIFO
- Interrupt functions: Data Ready, FIFO flags, pressure thresholds
- Supply voltage: 1.7 to 3.6 V
- High shock survivability: 22,000 g
Parts Required
I used an expansion board connected to the Micro:bit, this makes it easier to connect sensors using connecting wire
Schematic/Connection
I used the I2C connection for the sensor
Microbit | Sensor |
3v3 | 3v3 |
Gnd | Gnd |
SDA – 20 | SDA |
SCL – 19 | SCL |
Code Example
This uses the library from hhttps://github.com/adrien3d/IO_LPS22HB
[codesyntax lang=”cpp”]
#include <Wire.h> #include "IO_LPS22HB.h" IO_LPS22HB lps22hb; void setup() { Serial.begin(9600); Serial.println("IoThings LPS22HB Arduino Test"); lps22hb.begin(0x5D); byte who_am_i = lps22hb.whoAmI(); Serial.print("Who Am I? 0x"); Serial.print(who_am_i, HEX); Serial.println(" (expected: 0xB1)"); if (who_am_i != LPS22HB_WHO_AM_I_VALUE) { Serial.println("Error while retrieving WHO_AM_I byte..."); while (true) { // loop forever } } } void loop() { Serial.print("P="); Serial.print(lps22hb.readPressure()); Serial.print(" mbar, T="); Serial.print(lps22hb.readTemperature()); Serial.println("C"); delay(300); }
[/codesyntax]
Output
Open the serial monitor and you should see something like this
P=1014.41 mbar, T=23.33C
P=1014.42 mbar, T=23.41C
P=1014.41 mbar, T=23.45C
P=1014.41 mbar, T=23.47C
P=1014.40 mbar, T=23.45C
P=1014.39 mbar, T=23.40C
Links
https://www.st.com/resource/en/datasheet/lps22hb.pdf