Breathing Back Pressure Data Analysis

I've uploaded some datasets of the blower in different modes, and the measured current and whether I am exhaling (0) or inhaling (1). The breath signal is generated by me pressing a button. Visualizing the current data suggest that is look very easy to detect the breath back-pressure in CPAP mode, and it seems possible to detect asychronous breathing in bipap mode.

This uses the visualization code here.

Current sensing is using this version of the schematic. It uses a 0.1 ohm 1 watt current sensing resistor. As the current draw by the BLDC motor goes up, the voltage across the sense resistor increases. This voltage passes through a small RC filter to smooth out noise before being read by an analog input on the Arduino. The reference voltage is a 1.1V internal reference which gives ~1mV of resolution using the 10bit ADC, which corresponds to ~10mA current resolution.