The Pebble Smart-Watch seizure detector is looking very promising. The software to run on the watch itself seems to be quite reliable at detecting shaking, without giving false alarms during normal activities.
The watch application is published on the Pebble App Store.
We have a rudimentary android app working that talks to the Pebble watch and acts as a web server that clients can query to get the alarm status etc. This is on the Google Play Store.
You can see a demo here: https://plus.google.com/+GrahamJones/posts/P9mWstgqP8N?pid=6111006693838101826&oid=106497137253664241170.
The main issue currently is that it works fine with the phone plugged in and charging, but if it is running on battery, the web server goes to sleep so does not work. For my application this is ok, because we will always be using it in the house, but for it to be useful for others we may want it to work outdoors – I think there is an android permission to stop the phone sleeping that I will have to use.
But, looking promising!
All source code is on the project Github Repository.