Received several sensors with Almond+ Kickstarter package, including a Securifi Door/Window Sensor.
Out of the box, several sensors show a Low Battery condition (the old Oct 2013 CR123A thing) yet continued to work for the next several months. All except this one sensor.
I thought it was a battery issue and ignored it until I got around to replacing the CR123A's which I did this past week. Same problem, this one sensor performed poorly, unreliably. Went through the usual, check the signal, reset and re-pair, even tested it with other magnets from other door sensors and no joy.
Then I tried a strong magnet I had laying around the garage and it worked !!
Just happened to have a couple tiny neodymium magnets laying around from an old project, dropped them into the housing and Success. This particular sensor, for whatever reason, just needed a little bit stronger magnet. Probably cost me a $1 in magnets to fix it, but that Door/Window Sensor is now very reliable.
Granted, should have been working in the first place, the whole battery thing is annoying and I'm sure I could have contacted Securifi Support for some satisfaction but for a dollar, I'm good.
$10 will get you 100 of the little guys and only a few are needed for this workaround fix.
http://www.amazon.com/Applied-Magnets-Earth-Neodymium-Discs/dp/B0012AUU84