EYE on NPI – TDK AVD Series Low-Profile Pressure Transmitters

This week's EYE ON NPI can make a big difference in how fast you get temperature and differential pressure data into your next design - it's TDK's AVD Series Low-Profile Pressure Transmitters (https://www.digikey.com/en/product-highlight/e/epcos/avd-series-low-profile-pressure-transmitters). They're all-in-one, ready-to-use temperature and pressure modules with ports, analog management circuit and a simple I2C interface that can quickly integrated into any microcontroller or microcomputer product. These are differential pressure sensor modules: that means they will be able to measure the positive or negative difference between two ports. Very handy when you just need to know how an internal cavity pressure measures up against outside air pressure. A common use case for these sorts of sensors is HVAC systems with filters to keep dust and debris out of the system where it could clog the motors or make air dirty. The filters eventually fill with dirt (https://www.flickr.com/photos/ivydawned/4020166274/) and the HVAC has to spend more and more energy to push the air through the clogged filter. While maintenance staff could check the filters weekly, for a large building that could get very time consuming. Instead, a sensor like this one could measure the differential pressure once a day and notify staff when the change increases past some threshold. We like the small, fully-integrated design of this sensor. There's a nice plastic enclosure, two barbed ports, and dual JST SH 5-pin (https://www.digikey.com/en/products/detail/jst-sales-america-inc/SHR-05V-S/759884) connectors that can be used for I2C connectivity. These aren't quite STEMMA QT connectors, but we were able to fashion a simple adapter for a demo. The I2C interface is very simple: there's no register map, just read 4 bytes over I2C and perform some simple calculations to determine temperature and pressure. We were able to throw together some Arduino code to read data and display it on an OLED in under an hour. The sensor comes in three varieties: 1.6kPa, 10kPa and 700kPa ranges (https://www.digikey.com/en/product-highlight/e/epcos/avd-series-low-profile-pressure-transmitters). The code and wiring is the same for all three, you can just change the range multiplier depending on which one you've got. Finally, for fast mechanical integration, there's a well-detailed dimensional drawing and a STEP 3D file with all the elements rendered in color. While this module is more expensive than a raw analog differential piezo pressure sensor - having the device packaged, linearized and digitized makes it very easy to integrate and install. And you can tell they did a really great job making this a quality sensor module! Best of all, all three versions of the TDK AVD Series Low-Profile Pressure Transmitters are in stock right now at Digi-Key for immediate shipment (https://www.digikey.com/short/90n7wrj5). Take the pressure off of yourself, and order today - you'll be able to add a professional quality, ready-to-install differential pressure sensor by tomorrow afternoon.