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The life and times of james Hart: his family, his music, life in Luton and his occasional escapes onto the internet.

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Saturday, 3 September 2016

Re-using an old Android phone as a DIY cycle computer

As first phones, the Samsung Galaxy Young gave the offspring a first opportunity to use a smartphone but without too much stress about losing / breaking it. It's a very basic Android phone (running 2.3.6 - Gingerbread) with a small screen and not much onboard memory, so it wasn't long into their teenage years before they saved up for slightly more sophisticated devices.

Consequently, these old phones, in their fold-over cases, have been sitting idle for a while. In the meantime, I've been looking into the latest generation of cycle computers - mainly the GPS enabled ones that can sync with fitness apps (such as MapMyRide, Strava) and wondered if it might be possible to make use of the GPS on a basic Android smartphone to give an idea of how fast and far I'm going. It doesn't make sense to spend upwards of £100 on a Garmin Edge if I can re-use some old technology with a screen, a GPS and a bit of processing power.


Since these phones don't have much memory, and run a rather old version of Android and have a tiny (compared to modern devices!) screen, I was a little concerned that there wouldn't be an app available for it. However, Endomondo downloaded without any problems, and seems to run very well. It's simple to set-up and use; I created an account on the main website, and used that to log in to the app. It can create workouts and routes for various different sports, and some had already been uploaded for the area I live, so I might try them! The only downside is that, to display the map, it requires an internet connection; although I downloaded the map tiles in Google Maps, Endomondo doesn't seem to be able to be able to gain access to them, so I couldn't view the map as I was cycling. However, this app definitely shows promise - the next challenge is to get it onto a bike!

Attaching it to the bike

I've always recommended a case to give a mobile phone that extra bit of protection; even more so, I tend to use one that folds over the screen so it doesn't get scratched. These aren't too expensive - we had already bought one for a couple of pounds from Amazon and it was this that I used as a basis for the bicycle mount. I removed the leather case part, leaving only the plastic enclosure, into which the phone clips nice and securely. Marking holes along a 2 to 2.5cm square in the middle of the enclosure, I cut, then filed, a pair of slots for a hook and eye strap to loop through, and applied a small piece of rubber padding (actually a self-adhesive tyre patch!) to the back of the phone to stop it slipping. This seemed to work very nicely - all I needed to do was trim the tie wrap down to the right length to encircle the handlebars and it was ready to go.

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Going for a ride

Fortunately the rain held off for long enough to allow me to go for a brief ride into town and along the cycle track to Dunstable. It seemed to work very well indeed - and didn't fall off, which was my main worry! When I arrived home and back into wifi coverage, it synchronised both trips with the site, and there it is! If I have one concern, it's that it seems to be measuring the speed a little high - the total journey time, distance and average speed work out at the end, but I wonder if it might be displaying the speed in km/h. Otherwise, though, I feel like I've saved a bit of money, and I think it's working very effectively. Battery life certainly seems sufficient to keep it going on an afternoon's cycle ride, even with the screen display set to wait 30 minutes before turning off. All-in-all a pretty good use for an old mobile phone, I think!


Posted by james at 6:29 PM

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