SparkFun Absolute Digital Barometer - LPS28DFW (Qwiic) Hookup Guide

Contributors: El Duderino
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Hardware Overview

In this section we'll take a closer look at the LPS28DFW and other hardware on these Qwiic breakouts.

LPS28DFW Absolute Pressure Sensor

The LPS28DFW from STMicroelectronics is a digital output absolute pressure sensor with a gel-filled metal lid protecting the sensing element from moisture making it ideal for applications such as water depth measurements or other pressure-sensing projects in wet environments.

Highlighting the LPS28DFW on the standard breakout. Highlighting the LPS28DFW on the micro breakout.

The LPS28DFW has two user-selectable measurement ranges (260 to 1260hPa and 260 to 4060hPa) with an absolute pressure accuracy of 0.5hPa and supports output data rates of 1 to 200Hz. The sensor supports communication over I2C and MIPI I3CSM interfaces (though I3C communication is not covered in this guide or the Arduino Library). The table below outlines some of the parameters for the LPS28DFW. For a complete overview of the sensor, refer to the datasheet.

Parameter Min. Typ. Max. Units Notes
Supply Voltage 1.7 - 3.6 V Breakouts run the sensor at 3.3V
Supply Current - 1.7 - µA Average Selection (AVG)=4 and Output Data Rate (ODR)=1Hz.
- 9.4 - AVG=128 and ODR=1Hz.
- 0.9 - Sensor in power-down mode.
Operating Temperature Range -40 - +85 °C
Operating Pressure Range
Mode 1 260 - 1260 hPa
Mode 2 260 - 4060
Pressure Sensitivity
Mode 1 - 4096 - LSB/hPa
Mode 2 - 2048 -
Relative Pressure Accuracy Test Conditions:
Mode 1 - ±0.015 - hPa Temp. = 25°C Press.=800~1100hPa
Mode 2 - ±1 - Temp. = 25°C Press. = 2060~4060hPa

I2C Interface

The standard size routes the I2C interface to a pair of Qwiic connectors as well as a 0.1"-spaced PTH header for users who prefer a traditional soldered connection. Both breakouts route the sensor's interrupt (INT) pin to a PTH pin.

Highlighting the communication interfaces on the standard breakout. Highlighting the communication interfaces on the micro breakout.

Both boards set the LPS28DFW's I2C address to 0x5C by default. Adjust the ADR jumper to change to the alternate address (0x5D) or open it completely to toggle the address using the ADR PTH pin (Standard size only). More information on this jumper in the Solder Jumpers section below.

Solder Jumpers

Both LPS28DFW Qwiic breakouts have three solder jumpers labeled: PWR, I2C, and ADR. The table below outlines the jumpers' label, default state, function, and any notes about their behavior.

Highlighting the communication interfaces on the standard breakout. Highlighting the communication interfaces on the micro breakout.
Label Default State Function Notes
PWR CLOSED Completes the Power LED circuit. Open to disable the Power LED.
I2C CLOSED Pulls the SDA/SCL lines to VCC (3.3V) through a pair of 10kΩ resistors. Open to disable pull-up resistors on the I2C lines.
ADR SEE NOTE Sets the I2C address of the LPS28DFW. I2C address is 0x5C by default. Sever the trace connecting the center pad to the pad labeled 0x5C and connect it to the pad labeled 0x5D to change the address.

Board Dimensions

The boards match the Standard and Micro form-factors for Qwiic breakouts measuring 1" x 1" (Standard) and 0.5" x 0.3" (Micro). The Standard breakout has four mounting holes and the Micro has one. All mounting holes fit a size 4-40 screw.

Standard Qwiic breakout dimensions. Qwiic Micro breakout dimensions.