Originally Posted by
jefnvk
I've used Pis and Arduinos at work, using them to devise a solution here is way overkill. Plenty of commercial examples can do exactly what I want cheaper and in a much smaller packaging.
As to the phone, I do generally use one in my back jersey pocket to record the track, but leaving the screen on all day kills the battery too fast, and pulling it out becomes cumbersome. Speed is fun to know, but what I really like being able to know is distance to turns and such, for better navigation.
I mount my phone to the handlebar using a Quadlock mount and case. It's very solid and secure. If I'm going to ride for more than an hour, I connect the phone to an external battery. With that, I can keep the phone's charge level up to 100% all day, and this is with one of the smaller batteries available; it's about the size of a computer mouse, a little longer and narrower. The battery sits in my tool bag which is lashed to the bottom of my saddle. The cable runs from the bag, along the top tube, to the phone. It's convenient enough for me, whether I want to keep the screen on or not. For rides of 90 minutes or less (which are most rides, for me), I either don't keep the screen on, or I watch the level. I've received warnings that I'm about to deplete the battery, but the ride hasn't been cut off yet after I turn the screen off.