A bioimpedance (BioZ) sensor with two sensing electrodes is employed to measure the chest impedance.  The breath-by-breath breathing rate is calculated using the time difference between two BioZ signal peaks, and the results are validated against a commercial respiration monitoring belt.  The experiment measurements show that the BioZ sensor patch can be used to monitor the breathing rate accurately in static conditions with a low mean absolute error (MAE) of 0.71 breath-per-minute (bpm) and can detect breathing rate effectively in a dynamic environment as well. 
BioZ
The recorded data is transmitted via a Bluetooth module to a computer for online data computation and waveform visualization. 
Bluetooth