It is a Micro-wave Doppler effect sensor. The principle is simple : it sends microwave and does the difference between the sended wave frequency and the response wave frequency.
The difference of frequency is proportionnal to the speed of the object it detects.
But, as you might expect it, I have a problem : I've spent some time working on the output signal, it's a sine signal which amplitude is around 10 to 100 mV depending on the size and the distance of the object.
My problem is that I can't find a SIMPLE solution to amplify this signal in order to use it with an Arduino. I've tried several Amp Op such as LM381 or TL082 but with no luck : the LM381 doesn't work with AC signals and the TL082 seems to not detect the input signal (so it can't amplify it!!).
Your link is not opening for me (times out, my problem I think).
Post your op amp circuit. A simple non-inverting summing amplifier with a gain of 50 running from +5V & Gnd with 2.5V of DC offset added should let you see a ~0 to 5V signal coming out for the arduino to convert.
Using a simple excel spreadsheet and some assumptions:
Vout/Vin = 5V/0.1V = gain of 50
Thus (1+R4/R3) = 50, R4=500 & R3=10 yields gain of 51, close enough
Plugging in steady state V1 = 0V, V2 = 2.5V/50, output voltage of 2.5V, R3 & R4 above,
yields R2 = 9 * R1. 100K & 10K are close enough
R1 = 10K
R2 = 100K
R3 = 10K
R4 = 500K
V2 = 0.05V
For V1 = 0.01V, Vout = 0.695V
For V1 - 0.1V, Vout = 4.868V
Similar results should be achievable.
If your op amp won't do that full of a voltage range, lower the gain and increase the offset:
V2 = 0.1V, R4=400K:
If you want is a square wave out then all you need is a single op amp and a potentiometer and voltage divider.
Put your input signal on the +input
Put +5 on one pot leg, the other to ground. From the wiper leg, 100K to 10k to ground. Junction of 100k/10K to op amp input. This will give you finer control of your 'trip point' for comparison. For examplem with the pot in the middle, wiper is 2.5V, but op amp will see ~0.225V. Dial the trim pot down until you get nice signal from the op amp with your 10mV input from the uwave device.
The max gain is something over 10,000 with the two stages. Note the 2.2 nF caps across the feedback resistors--they filter out the higher frequencies, so the circuit as given is applicable to low velocity situations like motion detection of people. According to the table at the end of the data sheet, at 10.525 GHz, doppler frequency in Hz = 31.36 * velocity in mph, so at say 10 mph f would be about 314 Hz and the 2.2 nF cap impedance would be much less than the 1 M resistors.
I try to use hb-100 to detect motion. I successfully build the suggested amplifier in the documentation. Now it reads the A0 analog input and write trough serial port to PC where I can display the waves, which frequency and amplitude is changing when I move my hand in front of the sensor.
Have anybody some example source code, to convert this usable speed information?
Can I have the size of the moving object with this sensor? Or the distance?
My project is speed detection of vehicles using HB100 sensor.
I require an amplifier circuit for the IF output of HB100 which can:
Amplify signals from micro volts to 8 volts.
Pass frequencies upto 3Khz.
(Optional) the output of the amplifier if possible should be a square wave.
Sir please send the picture of the amplifier circuit diagram. There is no one to help or guide
us here. We are fully dependent on your solution to this problem.
Micro volts suggests to me a moving coil or moving magnet hi-fi cartridge pre-amp.
That would get you to line levels.
Don't try to do it in all in one stage.
AWOL:
Micro volts suggests to me a moving coil or moving magnet hi-fi cartridge pre-amp.
That would get you to line levels.
Don't try to do it in all in one stage.
Thank You sir for your reply.
I have got a circuit given along with the product. The problem is,
Its bandwidth is only 5Hz-60 Hz, any frequency above that is getting attenuated. I require an upper cut off of 3Khz.
The amplification is from micro volts to 4 volts. But I require an output voltage of 9V.
I will post the amplifier circuit. Please suggest me suitable changes 1. To amplify signals upto 3Khz.
2. To increase the output voltage to 9V.
Check this Micro-Doppler radar Module at Ancortek, website : www.ancortek.com . It can be applied to industry Automation, Medical Monitoring/Diagnosis, and Safety/Security, education and lab
