LowPowerLab Forum

Hardware support => RF - Range - Antennas - RFM69 library => Topic started by: ztill on August 09, 2015, 11:09:07 PM

Title: Will a RF jammer disrupt communication
Post by: ztill on August 09, 2015, 11:09:07 PM

I am interested in building a robust alarm system for my home - I just ordered a few items from here to experiment.

I know there is no system that is devoid for all vulnerabilities, but would it be fairly easy to disrupt communication between moteinos by creating high rf power noise around 915mhz for a 915mhz module? Is there an easy way to detect if such interference is happening?

Title: Re: Will a RF jammer disrupt communication
Post by: Felix on August 10, 2015, 10:09:15 AM

Yes a jammer will jam any radio communication, not just Moteinos.
The radios have a capability to read the RSSI as a means to detect interference. The send function already has that check. However if you need to detect jamming then you might need to build a more complex algorithm for that purpose.
Another way is to use another channel or use a FHSS technique for communication. Even so a jammer that jams the whole 915 spectrum could cut communication but in general it's fair to say that it would take a very high tech thief to do that, the kind that would break into Louvre not at your house :)

Title: Re: Will a RF jammer disrupt communication
Post by: ztill on August 10, 2015, 02:35:37 PM

Thanks for the reply Felix.

I'll look into RSSI.. Here is a paper (http://e-collection.library.ethz.ch/eserv/eth:1182/eth-1182-01.pdf) that shows that RSSI goes down as the noise becomes stronger, and other techniques to detect jamming.