Hi, I was trying to build a circuit with a Doppler sensor to detect the motion. I have google some similar projects and find that they made a amplifier circuit before output the signal to Arduino. For example, on page 5 of amplifier circuit for HB100.
What is the reason to do that?
I am using MDU2400
from the data sheet, I don`t find any detail about the amplifier circuit. What should I pay attention to if I required to build the amplifier circuit by myself? Should I just use the amplifier circuit from HB100?