Originally Posted by
Aubergine
Yep that was my idea too. OP, here’s a pic of the Sanyo. As you see it mounts under the bottom bracket and runs off the front tire.
They worked better than bottle dynamos but not as well as a hub dynamo.
They operate on the REAR wheel.
I installed one on my spouse's bike. She rarely needs lights, but when she does, I can be sure she hasn't charged them, so this was a good choice. The drag annoys her, so I might eventually replace it with a hub dynamo. She doesn't want me to because of the weight, but she probably won't notice the difference.