Instructables

How to build a circuit which converts AC power from a bike dynamo to the USB standard

What: I will show you how to build a circuit which converts AC power from a bike dynamo to the USB standard for charing USB devices.
What will NOT be covered: Attaching and using a bike dynamo, the fine details of soldering,detailed information about electrical circuits, attaching the circuit to your bike.

Difficulty: Moderately Hard, due to soldering requirements.
                                                                                         How To Solder for beginners:
                                                    

Time: 1-3 hours
Required Tools/Equipment: Bike, Bike Dynamo (Bottle or Hub), Soldering iron, Electrical Solder, Wire strippers/cutters, Volt meter(Optional for testing), housing to attach the circuit to your bike.

 
  Note  Note:  Make sure you use electrical (rosin core) solder and NOT plumbing solder.  Using plumbing solder can damage the connections and circuit components because it uses a stronger acid flux.
 
Required materials (I will list the part numbers which I used from Newark): 
OKI-78SR-5 (7v-36v  to 5v DC voltage regulator)                                    $4.69
GSIB1580-E3 (Single-Phase Single In-Line Bridge Rectifier)                  $2.11
2222 021 16682(25v 6800 microF capacitor)                                         $5.83
2222 138 36109 (25v 10 microF capacitor)                                           $2.08
292303-1 (USB type A receptacle)                                                      $1.51
VECTOR ELECTRONICS – 8001 – PCB (Printed Circuit Board)            $25.66
WH18-00-25 (Hook-up wire 25FT 18 AWG)                                           $5.57
                                                                                       Shipping:     $10.00
                                                                         Total(Without Tax):    $58.66

 
Why: Imagine yourself cruising along on your bike and suddenly you get a flat.  You pull off to the side of the trail and start rifling through your saddle pack to grab your  cellphone and call for back up, but you discover that there is a problem, your phone is dead. Now you are stuck and the only thing you can do is walk to the nearest town, luckily it's only 10 miles away.  Now lets imagine a situation that is even worse than that, you are a cruising a long and your tunes cut out.Your iPod has died, and you were only half way into your ride. You cannot stop now but there is no music to keep you going, this is a problem.  What a nightmare that would be.  Now lets imagine that you had some mystical device, from the heavens themselves, which could power any USB device that you own. 

Disclaimer: I am not an electrical engineer, and this circuit has not been tested due to my soldering failures.  This is merely a DIY work in progress that I am posting for feedback and future improvements.
Caution Caution: Use at your own risk!
 
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pd0wdv6 months ago

I am sorry to correct you, but the wiring diagram is not correct:

the bottom lead of the diode bridge should go to the bottom connection (earth) of the generator.

Further more, this is a nice and simple project. Well done!