Mobile Power: Homemade USB Charger

Before heading out for a tour of the Pacific Coast, I hobbled together this USB charger to use with my SONdelux hub on a 700c wheel:

Please excuse the mess; I threw everything together the night before I left. The next version will be much sleeker. It weighs almost nothing and cost me only about $5. The circuit I used is a [very] slightly modified version of this one (which includes detailed instructions):

 I got most of my parts from Jameco with a couple additions from Radio Shack:

* Diode bridge rectifier 100V 1.5 amp [turns the AC current coming from your hub into DC, far left on the schematic]
* 2 Zener diodes 15V 5W [placed end-to-end at the beginning of the circuit for overvoltage protection; apparently you can hit 100V with these hubs which would fry your regulator]
* 2200 uF capacitor [for power smoothing, I might add a bigger on to future iterations]
* .47 uF capacitor [tantalum should be used for this and the next one]
* LM2940 regulator [this is a low dropout regulator, which means you will hit 5V at lower speeds. You could also use an LM7805, but they waste more voltage]
* paper clips and a binder clip [the heat sink for the regulator wouldn't fit into the box, so I just clipped some stuff onto it as a very rudimentary heat sink]
* 22 uF capacitor [tantalum]
* Female USB A [there are four pins on it, the outside ones are + and - and the middle ones should be soldered to each other for some devices to charge]
*Prototyping board [soldered everything on this, got it at Radio Shack]
*Project box [also from Radio Shack, although, with better planning, this could all be a lot smaller]
*9 volt battery leads

I added two new wires to my hub and wired them to my front rack, where I added the battery leads to be able to snap the charger on and off (or other things I make in the future):

I decided to use the the charger to charge an intermediary battery since I didn't want to risk frying my devices by giving them variable voltages when I slowed down or stopped. I also liked the idea of being able to charge anything I needed once I got to camp. I chose the inexplicably, but perhaps appropriately named Dynamo-On-the-Go battery from RAVPower which was able to charge my phone and mp3 player several times between charges [note: the first one I ordered didn't work, but the replacement seems fine so far]. If I wanted to charge my stuff directly while riding, I would still use the battery and charge my devices while charging the battery (they have separate inputs and outputs). There are some really small ones that would probably work well, like this one.

And here's the thing all hooked up:

So far, so good, although I really only had to charge the battery once on my twelve day trip. I cheated and stayed inside a couple times where I charged my phone. But I was able to charge the battery to full with the charger and fill up my mp3 player and phone. More road testing to follow...

Here are a couple shots from the trip:

Mark's first braze job is still holding together after some loaded trail testing. More photos on my photo blog.

Portland to Oakland, two weeks on two wheels

Just returned from a two week tour from Portland to Oakland with my oldest buddy in the world.
The ride out of Portland:
Chrome dome:
Clearcut road:
Arrival near Cape Lookout. Dave and Amanda showed us the rad route to the beach:

Cheese Nip:

Our two rigs at Umpqua lighthouse campground. Fourth of July weekend, hence the flags. We heard through friends that the flags might serve as camouflage for us and win us some social graces on the crowded roads.

A fresh bud knocked from a tree in the insane headwind we had just been riding in.

Butter herb mac and cheese, with Tapatio Doritos added. Mix this with cold beer and you've got a gut bomb party!
Brookings:
The Riv in the Redwoods
Double crotch shot in hollow Redwood:

Old bike logo in Fortuna:

We ran into this very friendly guy named Scott having coffee on the Avenue of the Giants. At first I didn't notice that he was riding an 85/86 Stumpjumper, but as you can imagine I was pretty pumped to talk to him about it. He was living the dream; he told us that 3 days a week he rides his bike to his canoe, throws the bike in, canoes down, and takes the bike back out to ride it to get coffee. Killer!
Avenue of the Giants:
Lunch at the totally incredible Peg House and a day off in the Eel River. NEVER DON'T STOP:
Balh Hornin'
Then there was this guy. We got a pretty good chuckle when he drank two bottles of wine and passed out perpendicular to his tent (inside):
At the finish of the Leggett hills:

Met our friend Tamar in Elk:
Rad old general store:
Fogggggggggy
And done! Lagunitas Pale Ale donut explosion on the ferry to SF:
Ryan and the Foggen Gate Bridge. The ferry was the right choice!