Hopefully this will be of interest to some of you in here. I'll try and keep it short and to the point, but here's the obligatory rambling introduction: As a result of no longer being a student and having a proper full time job and everything, I've found since August that it just wasn't possible for me to do anywhere near as much cycling as I'd been able to as a student - back then I could take a couple of hours in the middle of the day to make the most of the quieter-than-rush-hour roads and the better-than-darkness visibility - making up for the lost work time in the evenings, that would be no good for cycling anyway.
So in an attempt to not completely lose my fitness over winter I bought a turbo trainer, set it up with my bike in my flat, and bought a Zephyr HxM Bluetooth heart rate monitoring strap: when on the trainer, the usual metric (using Google My Tracks to get speed/distance stats via GPS) was obviously useless. Now, I could have course have set up my Cateye cycle computer on the rear wheel, but - aside from the fact that the transmission is directional and it refused to pick up the signal from the back when I tried - I figured that knowing my 'speed' indoors would be largely meaningless.
So I arrived at the conclusion that heart rate would be the sole metric of interest. Now, having bought the Zephyr HxM you'd think I'd be all set. Well, not exactly: see, most if not all of the Android apps for it combine heart rate monitoring with various other sources (e.g. GPS in My Tracks case) - and the result is that they don't actually do much of interest with the heart rate data beyond graphing it.
As there wasn't anything that would do exactly what I wanted, I set about developing my own heart rate monitoring application for Android - called Cardio Grapher. So for the last couple of months I've spent all the time that I would have been on the trainer working on this app. I released version 1.0 on Wednesday, and I've just released version 1.1 (which adds support for Android 2.1+; version 1.0 only supported Android 2.3.3+). Finally I'm starting to use it in anger and actually do the whole Winter miles bring Summer smiles thing

.
My reasons for posting here then:
- Hopefully Cardio Grapher may be of interest/use to some of you - it'd be great if others find it useful and benefit from my work.
- If anyone has an Android 2.1 device and a Zephyr HxM it'd be great if you could try it out and respond with a "yes it works"/"no it doesn't work, and this is what happens".
Features:
- Live graphs of your heart rate over the last 1, 10 and 120 minutes.
- User specific heart rate training zones, helping you get the most you can from your training (based on formulae from
http://www.machinehead-software.co.uk/bike/heart_rate/heart_rate_calculator.html).
- Audio alerts when entering and exiting training zones.
- Can be set to keep the phone's screen on when in use.
- Can be set to automatically switch the phone's Bluetooth adapter off and on again when connecting to the HxM times out (this is a work around for a bug in the Bluetooth implementation on some phones).
- Reports the remaining battery charge level of the HxM.
While it doesn’t yet do that much more than the existing solutions (I consider it to be Beta quality at the moment), my intention with it (as you may guess from the name) is for it to solely work with heart rate data. As such, I intend over time to explore a number of ideas for metrics that can be used to gauge the quality of a workout and to track progress.
Cheers,
Mr. Brightside
Relevent links:
http://www.piggott.me.uk/blog/2011/12/15/cardio-grapher-beta/
https://market.android.com/details?id=net.cardiographer
http://www.zephyr-technology.com/consumer-hxm
http://www.heartratemonitor-app.com/ (where I bought mine from)