# Adafruit LPS33/LPS35 Water Resistant Pressure Sensor ## Overview ![](https://cdn-learn.adafruit.com/assets/assets/000/076/550/medium800/sensors_4258_iso_02_ORIG_2019_06.jpg?1559951328) Sometimes you need to sense pressure when it's wet. And sometimes you need to know the relative changes in pressure as well as the absolute pressure. For the times you need to do both (or either), the LPS35HW is the pressure sensor for you. Combining protection from water intrusion with support for high precision relative and absolute measurements, this sensor will do what you need. With drivers for CircuitPython, Arduino, and Raspberry Pi, and support for I2C or SPI (Arduino only SPI support, for now) you'll be measuring pressure in moist situations in no time. Warning: ![](https://cdn-learn.adafruit.com/assets/assets/000/084/683/medium800/sensors_beauty_crop.jpg?1574279459) The LPS35HW has a fraternal twin, the LPS33HW. In nearly all respects the LPS33HW is the same as the LPS35HW however the LPS33HW has a bonus feature: a nozzle that can be used to seal it against an enclosure or perhaps a properly fitted tube of some sort. You'll want to make sure to use an appropriately sized o-ring to ensure a good seal. Like the LPS35HW, the LPS33HW chip inside is encased in a protective gel, however in the case of the LPS33HW, the gel is mentioned as being > ...designed for and proven to protect electronic components from long-term exposure to harsh environments such as water mixed with chlorine, bromine, commercial washing detergent and fuels, solvents and chemicals. Wow! That's a resilient sensor! Warning: ![](https://cdn-learn.adafruit.com/assets/assets/000/084/690/medium800/sensors_4414_quarter_ORIG_2019_11.jpg?1574279827) ![](https://cdn-learn.adafruit.com/assets/assets/000/076/551/medium800/sensors_4258_quarter_ORIG_2019_06.jpg?1559951438) # Capable sensors The ST LPS35HW is a water resistant barometric pressure and temperature sensor that is also safe to use in wet environments. The sensing element is nestled safely in a ceramic package and is encased in a waterproof gel that prevents water that gets into the sensor from interfering with readings. It does not carry any ratings for resistance to moisture so you probably don't want to take it to the bottom of the Mariana Trench, but it should work well for normal wet situations like weather stations or high humidity. ![](https://cdn-learn.adafruit.com/assets/assets/000/076/913/medium800/sensors_4258_kit_ORIG_2019_06.jpg?1560272994) Similarly the LPS33HW is ensconced in a protective gel that protects it from harsh environments. Additionally it is called out by the manufacturer (ST) in the datasheet as being suitable for applications such as weather station equipment or a moist, mouth-adjacent activity that we don't encourage. Let's just say it **seems well suited for things like sip-and-puff switches**. Along with not being afraid of getting wet, the LPS35HW and LPS33HW have 24bit pressure data and 16 bit temperature data, allowing it to deliver pressure readings with +/- 0.1% hPa accuracy. It can measure from 260 to 1260 hPa and is able to withstand pressure up to 20 times their measurement range. To help you take measurements to your requirements, the sensors also offer an adjustable data rate, as well as a low pass filter to remove noise from the signal. Finally, the onboard temperature compensation makes sure that your readings are always good and won't vary as the temperature changes. We placed these sensors on a breakout board with a 3.3V regulator and level shifting circuitry so it can be used by 3V or 5V power/logic devices. A small piece of header is also included, so you can solder it in for use with a breadboard. ## A Family Affair ![](https://cdn-learn.adafruit.com/assets/assets/000/084/691/medium800/sensors_33_stemma_conn_crop.jpg?1574279917) The **LPS33HW** also joins our growing family of boards with [SparkFun QUIIC](https://www.sparkfun.com/qwiic) compatible** [STEMMA QT](https://learn.adafruit.com/introducing-adafruit-stemma-qt)** connectors, allowing you to combine it with all sorts of [other sensors](https://www.adafruit.com/?q=adafruit%20stemma%20qt%20sensor), and even [displays](https://www.adafruit.com/?q=stemma%20qt%20display), all without needing to solder! Just plug and go/blow! ![](https://cdn-learn.adafruit.com/assets/assets/000/084/729/medium800/sensors_4414_demo_ORIG_2019_11.jpg?1574298062) - [Next Page](https://learn.adafruit.com/lps35hw-water-resistant-pressure-sensor/pinouts.md) ## Primary Products ### Adafruit LPS33HW Water Resistant Pressure Sensor - STEMMA QT [Adafruit LPS33HW Water Resistant Pressure Sensor - STEMMA QT](https://www.adafruit.com/product/4414) Sometimes you need to sense pressure in a damp or caustic environment. And sometimes you need to know the relative changes in pressure as well as the absolute pressure. For the times you need to do both (or either), the LPS33HW is the pressure sensor for you. Combining protection from water... In Stock [Buy Now](https://www.adafruit.com/product/4414) [Related Guides to the Product](https://learn.adafruit.com/products/4414/guides) ## Featured Products ### Adafruit LPS35HW Water Resistant Pressure Sensor [Adafruit LPS35HW Water Resistant Pressure Sensor](https://www.adafruit.com/product/4258) Sometimes you need to sense pressure in a damp environment. And sometimes you need to know the relative changes in pressure as well as the absolute pressure. For the times you need to do both (or either), the LPS35HW is the pressure sensor for you. Combining protection from water intrusion... In Stock [Buy Now](https://www.adafruit.com/product/4258) [Related Guides to the Product](https://learn.adafruit.com/products/4258/guides) ### STEMMA QT / Qwiic JST SH 4-pin to Premium Male Headers Cable [STEMMA QT / Qwiic JST SH 4-pin to Premium Male Headers Cable](https://www.adafruit.com/product/4209) This 4-wire cable is a little over 150mm / 6" long and fitted with JST-SH female 4-pin connectors on one end and premium Dupont male headers on the other. Compared with the chunkier JST-PH these are 1mm pitch instead of 2mm, but still have a nice latching feel, while being easy to insert... In Stock [Buy Now](https://www.adafruit.com/product/4209) [Related Guides to the Product](https://learn.adafruit.com/products/4209/guides) ### STEMMA QT / Qwiic JST SH 4-pin Cable with Premium Female Sockets [STEMMA QT / Qwiic JST SH 4-pin Cable with Premium Female Sockets](https://www.adafruit.com/product/4397) This 4-wire cable is a little over 150mm / 6" long and fitted with JST-SH female 4-pin connectors on one end and premium female headers on the other. Compared with the chunkier JST-PH these are 1mm pitch instead of 2mm, but still have a nice latching feel, while being easy to insert and... In Stock [Buy Now](https://www.adafruit.com/product/4397) [Related Guides to the Product](https://learn.adafruit.com/products/4397/guides) ### STEMMA QT / Qwiic JST SH 4-pin Cable - 100mm Long [STEMMA QT / Qwiic JST SH 4-pin Cable - 100mm Long](https://www.adafruit.com/product/4210) This 4-wire cable is a little over 100mm / 4" long and fitted with JST-SH female 4-pin connectors on both ends. Compared with the chunkier JST-PH these are 1mm pitch instead of 2mm, but still have a nice latching feel, while being easy to insert and remove. Out of Stock [Buy Now](https://www.adafruit.com/product/4210) [Related Guides to the Product](https://learn.adafruit.com/products/4210/guides) ## Related Guides - [CircuitPython Powered Sip & Puff with ST LPS33HW Pressure Sensor](https://learn.adafruit.com/st-lps33-and-circuitpython-sip-and-puff.md) - [Adafruit NeoSlider](https://learn.adafruit.com/adafruit-neoslider.md) - [Adafruit QT 3V to 5V Level Booster Breakout](https://learn.adafruit.com/adafruit-qt-3v-to-5v-level-booster-breakout.md) - [Alohamora Bottle](https://learn.adafruit.com/alohamora-bottle.md) - [Adafruit Bluefruit LE Shield](https://learn.adafruit.com/adafruit-bluefruit-le-shield.md) - [Using the Bluefruit Dashboard with Web Bluetooth in Chrome](https://learn.adafruit.com/bluefruit-dashboard-web-bluetooth-chrome.md) - [itsaSNAP Apple Health Status Board](https://learn.adafruit.com/itssnap-apple-fitness-status-board.md) - [Adafruit QT Py ESP32-C3 WiFi Dev Board](https://learn.adafruit.com/adafruit-qt-py-esp32-c3-wifi-dev-board.md) - [CircuitPython on the nRF52](https://learn.adafruit.com/circuitpython-on-the-nrf52.md) - [Adafruit Feather RP2040 with DVI Output Port](https://learn.adafruit.com/adafruit-feather-rp2040-dvi.md) - [Adafruit ADS7830 8-Channel 8-Bit ADC](https://learn.adafruit.com/adafruit-ads7830-8-channel-8-bit-adc.md) - [Adafruit HTS221 - Temperature & Humidity Sensor](https://learn.adafruit.com/adafruit-hts221-temperature-humidity-sensor.md) - [Adafruit I2S Audio Bonnet for Raspberry Pi ](https://learn.adafruit.com/adafruit-i2s-audio-bonnet-for-raspberry-pi.md) - [Simple Arduino-based USB VID & PID tester](https://learn.adafruit.com/simple-arduino-based-usb-vid-and-pid-tester.md) - [Adafruit DC Power BFF](https://learn.adafruit.com/adafruit-dc-power-bff.md)