Track Breathing with Compact Pressure Sensor

For the past decade or so, many of us have been obsessively keeping track of vital statistic s— such as how many steps we’ve taken in a day, pulse, sleep, and other statistics. Monitoring how many breaths we take, as hacker “rabbitcreek” notes in this write-up, is a bit more difficult. Methods include measuring force around your midsection, a temperature sensor, or sip/blow switches, but this project instead explores an analog thin-film sensor normally used for detecting washing machine water levels. Rather than water, the device is set up to sense the subtle increase in pressure during exhalation.

The setup uses the diminutive Adafruit Feather 32u4 Adalogger, which conveniently includes both a LiPo connector and micro SD card slot. This small size allows the board, along with the MP3V5004G 0 to 3.92 kPa pressure sensor, to fit in a very small space that can, in fact, be housed in a former pill bottle. An array of RGB LEDs can even be added to the gadget in order to provide visual breathing indication.

While the sensor is currently limited to showing how often we breathe, not how much volume, it’s a novel use for an inexpensive appliance sensor. While collected data could possibly be useful after the fact, the indication that someone is breathing at all would also certainly be useful. One interesting configuration pictured in the tutorial shows that device attached to a snorkel. This could provide a way for others to see whether someone is breathing normally in the water, or if help is needed immediately.