mmVital-Signs

Millimeter-wave vital-signs detection

The mmVital-Signs project aims at vital signs detection and provide standard python API from Texas Instrument (TI) mmWave hardware, such as xWR14xx, xWR16xx and xWR68xx.

Experiment Environment

Detection range covers the hemicircle area at 0m ~ 8.6m, refers to Part.3

Demo

Theory

• Biology

Typical body surface displacement parameters due to breathing and hear-beat are：

• FMCW Basics

Periodic linearly-increasing frequency chirps (known as Frequency-Modulated Continuous Wave (FMCW)) are transmitted by radar towards the object：

Transmitted FMCW signal is given by $$s(t)=e^{j\cdot(2\pi f_ct+\pi \frac{B}{T}t^2)}$$ , it means that we can measure the changes of phase in back waves to predict the movement as $$\Delta \phi = \frac{4\pi\Delta d}{\lambda}$$

• Chirp Configuration for Demo

100 ADC Samples per chirp. Chirp duration is 50 ms based on the IF sampling rate of 2 MHz

Vital signs waveform is sampled along the “slow time axis” hence the vital signs sampling rate is equal to the Frame-rate of system

Requirements