Bicycle iPhone and USB Charging
This was my pet project for about six months back in 2009: A bicycle-mounted system for generating electricity, storing it, and charging several USB devices, mainly an iPhone and a GPS tracking unit.
In 2024, fifteen years later, there are dozens of products on the market that serve this function, and it seems silly to build one from scratch. I’ve updated the conclusion of this document reflect that, but left the rest unchanged, since it’s a fun reference for people doing small electronics projects and goes on a few neat tangents.
Oh, and you’ll notice I rant a lot about how amazing the iPhone is on a bike, which may invite some eye-rolling, like, “no duh it’s amazing, Captain Observo.” Well, every human is now surgically attached to a smartphone by the time they enter Middle School, but in 2009 that wasn’t the case. It’s hard to imagine, but most people didn’t even have a cellphone, to say nothing of a smartphone.
Anyway, here we go!
Traveling on a bike with a perpetually-charged iPhone is fantastic. You think I’m exaggerating, right? Try it sometime. Then you’ll want to build a battery pack. How convenient, there’s a guide for that right here!
I started this project with very little engineering knowledge, and I’ve tried to put everything I’ve learned into these pages. My hope is that you, fellow geek and/or bicyclist, can use this information to create an electrical system of your own. I’ve also listed parts, so that if you want, you can go step-by-step and recreate what I’ve done.
The sections are listed on the right. Each one is packed with links, photographs, and Q&A pieces. The Q&A pieces are condensed; only the question is visible until you click on it, like so:
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Suppose you’re biking at night, on a route you’ve never taken, and the road loses shape and changes to dirt. The iPhone is right there on your handlebars, so you press a few buttons, and instantly you get a daytime satellite photograph of the entire woods. There in the center is a glowing dot, showing where you are. As you ride on, you can glance down at the dot and confirm that, yes, there’s the tree you should be seeing, and there’s the spot where the road bends,… et cetera. In addition, the iPhone is playing music for you. And checking your email. And if the woods are getting spooky, you can call someone up and ask them to tell you jokes.
All with one device. Frankly, it’s like having “cheat mode” for a bicycle. It turns your bike into a mobile command center. With a few bars of signal, I am just as connected to the digital world and my social network as I am when sitting at home.
Before we proceed I must warn you about two things: First, the materials I chose are expensive, relative to other materials out there. For example, to store power, I could have just bought a handful of those lithium batteries that power digital cameras and flashlights. Lots of people do; and there’s nothing wrong with that. Instead I purchased two Lithium-Iron Phosphate batteries – a new battery type that is very stable at high or low temperatures.
The second warning is this: You will need to make use of a soldering iron! Nothing fancy – just wiring. If that’s scary, here’s what you need to do:
Go scouting around town for big featureless buildings. Look in the windows of each one until you spot cubicles. Walk into the building and yell two sentences: “Does anyone here know how to use a soldering iron? Ten minutes’ work and I’ll buy you lunch.” Engineers love lunch.
And while we’re on the subject of engineers, I would like to thank some people:
- Matt, for his excellent advice about enclosure materials and manufacturing, and his proofreading.
- Tavys, for his endless patience explaining Ohm’s Law to me ten different ways until I got it, teaching me how to use a voltmeter, and answering endless n00b questions about battery behavior, regulators, circuit design, testing, and procurement. Could not have done it without him.
- Sherrila, who proofread, helped me with soldering, and has acted as “pit crew” on countless bike rides while I completed this project.
Happy hacking!
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