Reddit reviews Lowrider Dynamo Generator 12V 6W. Bike Light Part, Bicycle lightpart, Beach Cruiser, Chopper, Limo, Stretch Bike, BMX, Track, Fixie

Well if you have an exercise bike with a spinning wheel and had a sporting goods or cycle shop open near you, something like this is always handy. Also, some exercise bikes have them built in if they're they type that the display comes on when you start to pedal. Or if you get creative, an alternator off a car held to the bike wheel will have the same effect.

We have a decent number of power outages in my area from time to time so I've used a dynamo like that on a stationary bike to charge my cell and ecig in the past. Works pretty well and gives you something to do while waiting things out and reading a book.

Edit: Also a car battery or the battery out of a riding mower will work as well if you have a charger that will take 12v input.

• Bike Dynamo (12V Max)
  
• Adafruit LiPoly boost charger
  
• Li-ion Cell (3.7 V)
  
  Thanks for the correction on pronunciation, I am sure it will aid in my future communication. It seems that the dynamo I ordered is AC. I will have to verify using an oscilloscope or multimeter whether that is true or not.

That sounds really expencive... Have you thought about just attaching bike dynamos to the wheels, and using a simple arduino script to figure out the speed? Or have an RPM measurer at the middle of the wheel (like a computer-fan would work, those usually have RPM measuring built in, that you can also relatively easily read out). Or even have a dynamo-like little wheel pressing against the big wheel, where you measure the RPM of the small wheel. That way you could easily calculate the distance driven with this wheel (taking the circumference of the little wheel, and multiplying it with the RPM, would give you the distance/minute).