EYE on NPI - ST LPS28DFW Dual Full-Scale, Absolute Digital Output Barometer #EYEonNPI @DigiKey
Channel: Adafruit Industries
Date: 2022-08-04

This week's EYE ON NPI is taking us on a deep dive into the world of waterproof pressure sensors - it's ST's LPS28DFW Dual Full-Scale, Absolute Digital Output Barometer (https://www.digikey.com/en/product-highlight/s/stmicroelectronics/lps28dfw-digital-output-barometer), an easy-to-use I2C temperature and pressure sensor that can go down to 4060hPa for use underwater!

We have used and highlighted many pressure sensors (https://www.adafruit.com/?q=pressure+sensor&sort=BestMatch) over the years here at the 'fruit including the ST LPS22 (https://www.adafruit.com/product/4633), ST LPS25 (https://www.adafruit.com/product/4530) , ST LPS33 (https://www.adafruit.com/product/4414) and ST LPS35 (https://www.adafruit.com/product/4258). Yep that's a lot of ST pressure sensors! Each one has slightly different precision: like many companies making sensors, ST has gotten better and better at making sensors, with each new model getting better accuracy/precision.

The LPS28 is a big step up in capabilities - almost all baro/pressure sensors are good up to 1060hPA which is basically sea level pressure (naturally 1013hPA) or in a high pressure weather system.  The moment you want to go underwater (https://en.wikipedia.org/wiki/Underwater_diving), the ambient pressure increases rapidly by 1 Bar (equal to "1 Atmosphere" or 1000hPa) for every 10 meters. That is to say, 10 meters down you'll be at 2000hPa, and at 30 meters, 4000hPa! But, like we said - most pressure sensors folks use cannot be used at such low pressures - which is why this sensor is the diggity - not only does it have a waterproof gel but you can actually use it underwater!

The interface for this sensor is also nice and easy: I2C or I3C (https://blog.adafruit.com/2022/05/12/eye-on-npi-nxp-p3s0200gm-i3c-switch-with-hardware-select-and-enable-eyeonnpi-nxp-digikey/) with one address pin and one alert/interrupt pin. The sensors are calibrated in the ST factory and thankfully are loaded into the ASIC on boot, so you can just read the pressure directly from the I2C register address without doing any funky math.

Ready to dive into using this sensor? You are in luck as there's even an eval board available (https://www.digikey.com/short/42rrvp2v) for quick connection and testing without any soldering required. And of course, this ST LPS28DFW NPI is available and in stock right now at Digi-Key for immediate shipment (https://www.digikey.com/short/1wrmj51m). Order today and you'll be swimming in sensor data by tomorrow afternoon!