Faraday bag for presence sensor?


(Mark Nelson) #1

I have a next door neighbor who has a key to my house. I’d naturally like to have her use a presence sensor, so when I see the door open event, it is accompanied by the return of the sensor on the key ring I’ve given her.

This would all work great if not for the fact that she is in the townhouse immediately adjacent to mine, so her presence sensor shows up whether she is in her house or mine.

I have a backpack and suitcase with mesh lined pockets that are supposed to block cell phone reception. (They seem to do that.) But the don’t block the presence sensor.

Wrapping it up in a couple of turns of aluminum foil does the job.

Putting it in a stainless steel sauce pan with a steel lid does not block it.

What I am looking for is a handy, small, easy to use container that is very effective at blocking the presence sensor. Then I can ask my neighbor to keep the key in that until she comes over the house to put away a package or whatever.

Given the failure of the sauce pan, I’m guessing an Altoids tin will fail as well, although I haven’t tried it yet.

Anyone given this odd problem a try?

  • Mark

(Alex) #2

Pop out the battery or reinsert the plastic tag that keeps the circuit open?


(Chrisb) #3

Wrapping it up in a couple of turns of aluminum foil does the job.

Aluminum foil you say??

On a serious note, what about wrapping the inside of a container in foil? A small box or whatever (with a lid), lined with three or four layers of foil might be enough to block the signal.


(Mark Nelson) #4

That’s a pretty awkward thing to be asking someone to do every time they use the key. Remember, this is my neighbor, doing me a favor :slight_smile: