Doppler Sensor circuit

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?

They used an amplifier because the signal output by the sensor is too small to be measured by the Arduino.

For your sensor, I suggest to follow the manufacturer's recommendations. Surely there is an application note for it. If not, you will have to do some investigation.

jremington: They used an amplifier because the signal output by the sensor is too small to be measured by the Arduino.

For your sensor, I suggest to follow the manufacturer's recommendations. Surely there is an application note for it. If not, you will have to do some investigation.

Thanks for your answer. I have sent the email to the company and hope they will have one for me. But if I have to investigate one, how can I know the rate of amplification that I need?

The results of your investigation will tell you what you need to do. If the signal is 100 times too small to detect, amplify by a factor of 100.

You should have a look at these modules I have tried and that work quite well

RCWL-0516-microwave-radar-sensor-module-Human-body 0.47 € (free shipping)

rcwl-0516-1.png
rcwl-0516-2.png

Whandall: You should have a look at these modules I have tried and that work quite well

Thanks for you suggestion, do you mean that you can use this module directly with your Arduino without any amplification? If yes, I think I`ll get some and try ;)

Yes, you need no other components or libraries, it's just a digital signal.

In combination with ESPs some people reported false triggers, but a filter in the power rail can solve that.

I tried the modules with 5V Arduinos (some with NRF24L01+) and they work well.

I just found that for doppler sensor below 10GHz they usually used 4 Pins or more. For doppler sensor above 10GHz there is only 3 Pins, Vcc GND and IF. What does IF means? Why we only need one pin in high frequency module?