X-band Motion sensor

Hi,

I have recently purchased an X-band sensor from a nearby store and i tried connecting it to arduino powering it up and Using analod read to read the sensor value, but the sensor shows constant value of 14 and there is very minute or no change when i try to move in front of it, the sensor has also not got any pot for sensitivity adjustment .

here is the link of the sensor

http://www.ebay.com/itm/Wireless-Module-Microwave-Doppler-Radar-Motion-Sensor-/201344051790

the sensor is the same without pot for sensitvity adjustments, i tried searching about the sensor but could'nt find anything, can you also help me with the schematic to add the sensitivity pot, please help.

thank you.

Some doppler radar sensors output a sine wave that is the difference of the sent frequency and the received frequency. http://www.egr.msu.edu/classes/ece480/capstone/spring10/group05/documents/justin_app.pdf

The received signal is then mixed with this set signal, which produces an output that is a sinusoid containing the frequency difference between the output and receiver signals.

Without the datasheet, you are working in the dark. Do you have an o-scope?

i am usig this for motion detection not for speed measurements and yeah i do have the data sheet, no i dont bt i can use one from the school lab i will try to find the output waveform but how do i read the waveform using ardunino. My plan is to sound an alarm when motion detected.

here is the pdf of sensor specs provided by the seller: http://www.robomart.com/index.php?route=account/product2pdf&productid=507

he has written that a sensitivity trim pot is provided bt i see no pot here. can you please help.

That datasheet needs some improvement. I don't see any interface pins on it. Besides the power and ground pins, there is supposed to be an Output pin and an IF pin, correct?

The Output pin is supposed to output a digital signal.

The frequency of the Output pin's high/low signal oscillation corresponds to the speed of the motion.

If there is no Output pin, and you are trying to use the IF pin, then this applies:

The magnitude of the Doppler Shift is proportional to reflection of transmitted energy and is in the range of microvolts (?V). A high gain low frequency amplifier is usually connected to the IF terminal in order to amplify the Doppler shift to a processable level.

yeah there is only an if pin and no out pin so how do i read the signal using arduino and i dont think it has an amp too do i have to connect an amp exterally from the output ? will ua741 do the job. i have seen the sparkfun sensor it has a second board with the potentiometer connected if anyone who has the sensor can open it up and post its pic it might help.

the sparfun sensor is something like the one in the above link.

You will probably need the amp and a frequency to voltage converter. That would be the easiest. Here is one that is recommended for the device you are using. It has the hi-gain amp and frequency to voltage converter in one package. http://www.ti.com/lit/ds/symlink/lm2907-n.pdf

edit: Or with the Parallax unit, you can check the OUT pin (should be digital) and time the change from LOW to HIGH and HIGH to LOW. You can poll it or use an interrupt.

ok but i have found a sample schematic which is linked below would this serve the cause like the schematic is basically amplifynig the if output so once the output is amplified i can read it ?? the link shows three schematics but doesnt xplain what each one does can you help me with it ?

http://www.aliexpress.com/item/Wireless-X-band-microwave-Doppler-radar-detector-probe-sensor-module-10-525GHz-HB100/755702442.html

I told you how. You need to connect the OUTPUT to a digital pin that supports interrupts. That is the easiest for me. Personally, I would set one interrupt( LOW to HIGH or rising edge) and track the time (milliseconds or microseconds) between interrupts.

okay i got it thanks for the help :)

plz send me code of 10ghz x band motion detector for range 9meter including frequency measurement upto 9 meter

AMBREEN: plz send me code of 10ghz x band motion detector for range 9meter including frequency measurement upto 9 meter

Please don't HIGHJACK an old thread on the forum. Start your own. But no one here will supply code to you or anyone else. We will help you with your effort.

What have you done so far?

Paul