Author Topic: low power MicroWave for intrusion  (Read 860 times)

MoonKnight

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low power MicroWave for intrusion
« on: August 24, 2016, 08:44:23 AM »
I'm trying to find a low power Microwave for a curtain detector im designing. needs to have about 15m range, and low current.
can you recommend some options? or point me the right place to start my research?

overlord

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Re: low power MicroWave for intrusion
« Reply #1 on: September 16, 2016, 12:43:46 PM »
Hello,
you need to have a multi sensor design. Some commercial battery powered radar sensors have an additional PIR sensor which does not waste so much power.
If the PIR sensor is signaling Motion turn on the radar and analyze waveform to filter out small animals and high speed movements from larger intruders. (FFT)
A typical radar sensor is using 30-40 mA when operating, but some of them can be pulsed with a certain duty ccyle to save power up to 1:1000
This beast is very sensitive. I have finished the analog circuit. FFT is still in the making.
https://www.conrad.de/de/universelles-radar-sensormodul-bb-thermo-technik-rsm-3650-betriebsspannung-33-v-502374.html but US has other frequencies!
There are very good papers on the following websites, describing several aspects on how to interface radar sensors in the analog and digital parts of the circuit:
http://www.innosent.de/en/services/downloads/application-notes/
http://www.innosent.de/fileadmin/media/dokumente/Downloads/Application_Note_I_-_web.pdf describes analog amplifier circuit
http://www.innosent.de/fileadmin/media/dokumente/Downloads/Application_Note_III_-_web.pdf describes pulsing to save power
An FFT example with that sensor is here: http://shop.weidmann-elektronik.de/index.php?page=product&info=9&dl_media=106
My plan is to use low power pir + radar sensor with Moteino to have an intelligent animal resistant intruder alert to avoid false alarms.
But first I need to understand the Moteoino Platform more deeply especially low power design.

Best Regards,
René