Wednesday, October 02, 2019

Wandering Tag - Discreet GPS tag for people and pets

It's been a while since I've posted any ramblings.  Those (few) souls who have been following my sporadic blogging and rants (thank you all dozen or so of you ;)  may remember me going on about "elderly monitoring" (I even had a side blog addressing this).

An decenet Elderly monitoring system would include some lightweight tracking capabilities (i.e. for early dementia sufferers who tend to wander from the house).

I've been working on and off of such a device.  I kept running into walls regarding how to do long range communication of geolocation.  Cellular is obvious but is costly, requires a "subscription" and is at the mercy of the telcos. I wanted something more in control of the user (consumer).  Basically: No subscription needed.

Enter LoRa.  Well, enter LoRa like capabilities: hundreds of meters range RF.  In testing some simple LoRa modules I've been able to get reliably around 800 meters (approx 1/2 mile), in a sub-urban (e.g. building, trees, hills, etc) environment, with a small trace antenna broadcasting to a large whip antenna (at 915Mhz).  I should be able to get further but these initial tests were with conservative bandwidth and spread factor settings.

This is actually an adequate range to track a "wandering" elderly person. When my mother-in-law lived with us and she would "take off" early in the AM (before we woke),  we always found her within a quarter to half mile radius (siting on a bench or at the local McDonalds).

In addition, this is probably adequate range for tracking pets (e.g. dogs that get out of the yard, cats that decide to go missing, etc).  So, I'll probably focus on that as an initial target.

I've gotten requests for pointers to "pet tracker" products.  I found a few, with Amazon's Fetch  being the gorilla in the room.  (Amazon's solution sounds like yet another way for them to gather more private data on people... I don't want to do that).

Now, to be clear,  I'm talking LoRa and not LoRaWAN.  I know that there are asset tracking devices out there that do LoRaWAN (and rely on infrastructures like the Things Network).  There are also "Tile" trackers that rely on social networks (i.e. people with apps installed on their phones that help the "community" find a lost pet).

What I want is a completely private system that requires no external "subscription" or "social network".  So, you would run a LoRa base station in your home (e.g. nothing fancy, maybe an ESP32 + LoRa + large antenna) and talk with it using your smartphone via Wi-Fi or BLE.  The basestation would also be "portable" so you could take it with you (walking or in a vehicle) to do live tracking of the pet.

Of course, it may make sense for you to use something like twilio to forward events to your smartphone when you aren't home, but that would be an option (not a requirement).

I am working on this now and have made quite interesting progress.  I intend the design and code to be open sourced (in particular: GPL'd) and there will be some interesting sizing as well as power saving tricks.

More to come... stay tuned.