My son found this in our yard… and now we’re wondering what this strange thing is. Do you recognize what’s in the photo?…

• Hub Dynamo – built inside the wheel hub (more modern but still mechanical).

Pros of the old dynamo lights

• No batteries needed 

• Works whenever the bike moves

• Durable and simple

Cons

• Light becomes dim when riding slowly

• Adds a little resistance while pedaling

• Can slip in rain if it touches the tire

 These generators were very common on bikes in Europe and older bicycles around the world.

If you want, I can also show you pictures of old bicycle dynamos or how to connect one to modern LED lights.