# New product: LPS25H pressure/altitude sensor carrier

Posted by Kevin on 28 May 2014
Tags: new products

We’ve just released a carrier board for ST’s newest pressure sensor, the LPS25H, and we’re also lowering the price of our LPS331AP carrier.

Like the LPS331AP, the LPS25H provides pressure readings over a range of 260 mbar to 1260 mbar (26 kPa to 126 kPa), and this data can be used to calculate the sensor’s altitude. Our LPS25H carrier mounts the sensor on a 0.4″ × 0.8″ board (0.1″ shorter than our earlier LPS331AP carrier) that breaks out all of its pins, and as usual, we’ve included level shifters and a regulator to make it easy to use in a 5 V system.

Compared to its predecessor, the LPS25H features improved accuracy and reduced noise in its pressure readings. The difference is noticeable in a comparison of altitude estimates from two stationary sensors:

The LPS25H also adds an entirely new feature: it has an embedded FIFO (First In, First Out) buffer, which can be used to store a number of readings for simultaneous transmission, or it can calculate a moving average of up to 32 pressure readings. This averaging smooths the noise in the output even more, as the following graphs demonstrate:

To help you get started with the LPS25H, we will be updating our Arduino library soon to support it. In addition, we plan to do some more comprehensive tests to better demonstrate how the LPS25H, with its moving average feature, compares with the LPS331AP and other pressure sensors.

Kevin,

The LPH25H has several settings for sampling rate of pressure and temperature, averaging sample size, and separate averaging in the FIFO. I would be interested to see the various LPH25H register settings used for the test. Is the code available?

Jeff
Hi, Jeff.

The data for this comparison was taken with a sampling rate of 12.5 Hz for both sensors and all other settings left at their power-on defaults (except for additionally enabling the hardware moving average for some tests); see the enableDefault() function here:
https://github.com/pololu/lps-arduino/blob/master/LPS/LPS.cpp.

- Kevin