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Archive for the ‘sleep apnea’ Category

If you wear a CPAP (Continuous Positive Airway Pressure) mask to treat obstructive sleep apnea, you may wake up to find that you’ve flung the mask off during the night or adjusted it to the point that there’s a large air leak. To help with this problem, ‘ArtSuzhou’ has developed a CPAP monitor that measures air pressure via an MPXV7002DP sensor—often also used to determine the airspeed of RC models.

The device is controlled by an Arduino Nano, and when it detects improper pressure readings in alarm mode, it activates a small buzzer, displaying a “check mask” message. It can also be set up to run in manometer mode in order to observe pressure changes. 

More information—including required parts, print files, and code to make it run—can be found here.

CPAP (Continuous Positive Airway Pressure) machines can be life-changing for people with sleep apnea. [Scott Clandinin] benefits from his CPAP machine and devised a way to improve his quality of life even further with a non-destructive modification to monitor his machine’s humidifier.

With a CPAP machine, all air the wearer breathes is air that has gone through the machine. [Scott]’s CPAP machine has a small water reservoir which is heated to humidify the air before it goes to the wearer. However, depending on conditions the water reservoir may run dry during use, leading to the user waking up dried out and uncomfortable.

To solve this in a non-invasive way that required no modifications to the machine itself, [Scott] created a two-part device. The first part is a platform upon which the CPAP machine rests. A load cell interfaced to an HX711 Load Cell Amplifier allows an Arduino Nano to measure the mass of the CPAP machine plus the integrated water reservoir. By taking regular measurements, the Arduino can detect when the reservoir is about to run dry and sound an alarm. Getting one’s sleep interrupted by an alarm isn’t a pleasant way to wake up, but it’s much more pleasant than waking up dried out and uncomfortable from breathing hot, dry air for a while.

The second part of the device is a simple button interfaced to a hanger for the mask itself. While the mask is hung up, the system is idle. When the mask is removed from the hook, the system takes measurements and goes to work. This makes activation hassle-free, not to mention also avoids spurious alarms while the user removes and fills the water reservoir.

Non-invasive modifications to medical or other health-related devices is common, and a perfect example of nondestructive interfacing is the Eyedriveomatic which won the 2015 Hackaday Prize. Also, the HX711 Load Cell Amplifier has an Arduino library that was used in this bathroom scale refurb project.


Filed under: Arduino Hacks, Medical hacks, The Hackaday Prize


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