It is ages since I updated everyone on where we are with a replacement for Pebble Watches (Note that Pebble watches are still available, and are the lowest cost device I have found to use as a seizure detector, so I’d get one while they are available!)
A brief update on each of the trials we have been doing over the last year below. Note that Ben’s work means that Android Wear is well in the lead at the moment!
I got as far as a proof-of-concept for using an accelerometer chip with a small wifi enabled microcontroller (ESP8226). (See Custom Hardware Seizure Detector) But I struggled to get the power consumption down enough to get the battery life I needed. I also realised that realistically, for most people to use it, I’d have to manufacture it and sell it, which is a bit much of an undertaking for me, so that is on hold for now.
Garmin IQ Watches
This is a possibility, but I have been a bit disappointed with the reliability and memory leaks – I could definitely get it working though with a few evenings work on it. They are quite expensive compared to Pebbles though (£180 from amazon)….But Benjamin can tell it is not a Pebble and refuses to wear it, so I am using it for running at the moment!
I started on a proof-of-concept but didn’t get it properly connected up (I had some maths issues in the fourier transform library for android, which was not giving the same numbers as the one I use on pebble).
Ben Geisler has made great progress in getting the seizure detection working on Android Wear watches, and integrating it with the OpenSeizureDetector Alarm System. He has also got heart rate monitoring working too. His source code is on Github: https://github.com/mechanodroid/AndroidWear_SD/
So Ben’s work means that of all the alternatives I have looked at, Android Wear is looking like the closest to something we can release – over the next few weeks I will aim to incorporate Ben’s work into the main OpenSeizureDetector app and release it for testing.
We recently noticed that the battery life of our original Pebble was reducing, and it was becoming borderline if it would make it through the night (we need it to run from about 19:00 to 08:00 the next day – 13 hours).
I was surprised to find that increasing the “Data Transfer Period” from 20 seconds that I was using to 30 seconds made a huge difference to battery consumption – it easily lasts over night now with significant margin.
I think this must be because the gap between bluetooth transmissions is now long enough to allow bluetooth to go to sleep in between, which it was not doing previously, but I don’t know enough about bluetooth to know if that is true or not.
So, if you are having trouble with battery life, change Data Transfer Period (in pebble settings) to 30 seconds.
I would only do this once you are happy that the system is working properly, because it means that the data on the phone display will only update every 30 seconds, which is a long time to wait if you are testing it. It also means that initial start-up will take longer, because the system waits on the start-up screen until it receives a routine data update.
Changing the Data Transfer Period does not affect the alarm response though – if the watch detects a warning or alarm condition it sends data immediately, irrespective of the Data Transfer Period setting.