I cycle quite a lot, and I always carry my iPhone: not merely in case I need to call a ride home after a severe mechanical failure, but also for GPS navigation and to harvest data about my heartrate, pedal cadence and wheel speed. I think my Pebble watch has the potential to significantly enhance this setup.
The iPhone battery doesn’t last very long if I have the screen on with the brightness turned up all the time, so I can’t have the phone’s data accessible to me at all times: I have to stop cycling and fiddle with the phone if I want to look at the maps it contains or see what my heartrate/speed/cadence numbers look like. In practice this means I only look at the phone when I am aware that I am lost; this wastes a lot of time because I have often been lost for quite a long time before becoming aware of it. It also means that I can’t train to heartrate zones or use the cadence data to inform my gear selection on climbs.
My Pebble watch gives me a potential way around this: because its screen doesn’t need to be backlit and consumes minimal power unless it is being updated it can display everything I am interested in without consuming its battery or the iPhone’s battery.
There are two things which need to exist to make this a reality: a mechanism to get the data I want from my iPhone displayed on my Pebble and a mechanism to attach the Pebble to my bike where I can see it easily. For the former I have to wait until the Pebble guys open up their API to third-party developers, although I can already start using the preview watchface SDK to work on what the data display will look like.
However, I can build the bike-attachment mechanism now. I decided to design a mount to attach it in the stem area because the handlebars are a busy place on a road bike: I need most of the space for my hands and the small central area is (a) tapered and (b) significantly interfered-with by cables.
An interesting innovation I first saw on this iPhone mount on Shapeways is to replace the headset top cap; I like the idea of mounting the watch above the steerer tube because it means the strap can lie along the top of the stem where it can be tied down out of the wind with a velcro strap. I didn’t want to replace the top cap because it loaded in a complex way and its integrity is relatively important.
I therefore designed my Pebble mount to replace the topmost 5mm spacer in my headset stack. You can have a look at my 5mm spacer-replacement bike mount for Pebble watch on Shapeways, and as soon as I have received my order and validated it I will make it available for sale. Of course if it fails to work in some way I will be redesigning it instead.