It's been a while since I've posted about my home monitoring system.
A couple of years ago, my Mother-in-law lived alone in a Condo and was prone to leave her stove on accidentally and other forgetful things. I started working on a home care monitor for the "Independent Elderly". It would include basic occupancy trackers, water overflow detectors and stove/kitchen monitoring (to make sure it isn't left unattended and to monitor her eating habits).
Well, fast forward to.. my dementia diagnosed Mother-in-law moved in just over a year ago. So, the problems are a bit different. She wanders. She gets up in the middle of the night to go to the bathroom and can't find her way back to her bedroom. She may go upstairs in the dark and stumble or venture outside. Sometimes, during the day she may decide to walk home... to her childhood home, several states away. She is old, but fast.
The current system uses "cheap" X10 RF motion detectors and door monitors. I can review past activities (e.g. when did she get up this morning? Did she frequent the bathroom last night?) or I can be alerted to the house door being opened (Is she just checking the weather? Is she going to sit on the porch? Is she going to make a run for it?).
The alerting system consists of some software I wrote (runs under Linux on a small Intel NUC PC) and it, currently, sends XMPP (Jabber/Chat) messages to a cloud server (on Digital Ocean) which runs Prosody XMPP server. My wife and I are connected to this server using XMPP chat software (Xabber) on our Android phones. We can query the monitoring system from our phone or be chimed when the door opens.
It has run well for a year now. :)
But, now that my Mother-in-law is prone to taking long unannounced walks, this system is not enough.
The phone chimes when the door is opened. Is it one of the kids? Is it her checking the weather? Is the door already opened from a previous check? Is she *really* still sitting on the porch 10 minutes from now?
So, after an early phone call one morning, from the Police (she managed to get several blocks from the house before sunrise), we decided we needed to invest in a tracking solution.
Most tracking solutions either involve GPS (battery drain, and overkill -- if we know that she has left we can pretty much find her in a matter of minutes -- if we know she has left.
Not a lot of solutions out there. Found one on an Alzheimers website. It *only* requires recharging every 48 hours. Ugh. What do we do while it charges? Do we need to buy two?
So, I decided to look into BT LE (Bluetooth LE). I had built several BT LE tags years ago and was interested to see what the state of the art was today. Apparently, Fitbit uses BT LE beaconing. That is, every second or so it broadcasts it's address so your phone can handily connect to it on demand.
BTE has a very limited range, but that's okay.
Also, Apple has been pushing "iBeacon" for their own (non-elderly) tracking purposes. They have a spec and a number of hardware vendors. I found this tag on Amazon for $14. Although meant to be used with Apple devices, it does a simple BTE beacon/broadcast that I can readily track. This is perfect size to be "hidden" in her purse (in a small crevice/pocket) and the battery should last 6 months - 1 year (I'll assume 3 months and schedule an early battery replacement).
Armed with the BT 4.0 PCI card in my NUC, I attacked this challenge a week ago. Now I have a rudimentary system that will let me know when my Mother-in-law has ventured beyond the front porch. My android phone (running Xabber) is notified whenever the tag goes out of range.
There is a lot of work to perfect this, but I am happy with the preliminary results. I will be moving the notifier beyond the phone (maybe home media -- DNLA/TV/etc or just speakers on the NUC) and making it work locally in case we lose Internet connectivity.
I will be releasing the software into open source within the next few weeks.