schematics HB100
http://www.aliexpress.com/store/product/Wireless-X-band-microwave-Doppler-radar-detector-probe-sensor-module-10-525GHz-HB100/915786_755702442.html


http://www.avrfreaks.net/forum/hb100-radar-module

https://www.youtube.com/watch?v=dGlPFnHuHr8
http://interface.khm.de/index.php/lab/interfaces-advanced/frequency-measurement-library/


https://seelio.com/w/egv/ghost-vision-non_contact-heartbeat-monitoring?student=johnlee