ESP8266 and LPS22HB absolute pressure sensor example

In this article we look at another absolute pressure sensor – this time its the LPS22HB

Once again lets look at this sensor from the manufacturers perspective

Description

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 List

Here are the parts I used

Name Links
Wemos Mini
LPS22HB
Connecting cables

 

Schematic/Connection

 

esp8266 and LPS22HB
esp8266 and LPS22HB

 

Code Example

This uses the library from https://github.com/adrien3d/IO_LPS22HB

This is the default example which works fine

 

/***************************************************************************
  This is a library for the LPS22HB Absolute Digital Barometer

  Designed to work with all kinds of LPS22HB Breakout Boards

  These sensors use I2C, 2 pins are required to interface, as this :
	VDD to 3.3V DC
	SCL to A5
	SDA to A4
	GND to common groud 

  Written by Adrien Chapelet for IoThings
 ***************************************************************************/

#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);
}

 

Output

Open the serial monitor and you should see something like this – I put my finger on the sensor, hence the value is rising

P=983.26 mbar, T=27.88C
P=983.22 mbar, T=28.27C
P=983.24 mbar, T=28.60C
P=983.24 mbar, T=28.93C
P=983.27 mbar, T=29.23C
P=983.24 mbar, T=29.50C
P=983.24 mbar, T=29.71C
P=983.25 mbar, T=29.89C
P=983.26 mbar, T=30.05C
P=983.25 mbar, T=30.21C
P=983.23 mbar, T=30.34C

I wanted to check the pressure out so I visited the following website – https://www.worldweatheronline.com . There are several others.

They stated that the pressure was – Pressure: 992 mb

So not to bad

Links

https://www.st.com/resource/en/datasheet/lps22hb.pdf

 

 

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