Bicycle Exhibit

Hello Everyone
I work in the exhibits industry and am updating an older exhibit for a science center and need some advice on incorporating Arduino into it.

The exhibit is a children's bicycle, stationary with the rear wheel lifted and covered so that the kids can pedal freely but can't stick their fingers in the spokes. On the wall in front of the bike is a screen with a static image saying "Start pedaling". Once the child started pedaling the bike, the screen switches to POV footage of a helmet cam of someone biking. The intent of the exhibit is for kids to learn hand signals and bike safety.

10 years ago, when it was created, they used a small generator, a series of dvd players and switching boxes to make it all work. The weak spot is the generator and the kids would burn it up about once a month. This facility sees over a 1000 kids 0-10 years old every day so the exhibit gets a lot of abuse.

My goal is to remove the mechanical components and use arduino to make this exhibit fairly maintenance free. All the media will be updated and put onto a basic media player. I need advice on the right components to use to trigger the POV media once the kid is pedaling the bike. Optical sensor maybe? I have a basic working knowledge of arduino and I know there are several ways to accomplish this but I'm not sure which one is best. Thank you in advance for any help and advice you can offer. Cheers

You might consider a Hall magnetic sensor. I believe that's what the bike computers use.

Optical sensor and slots in the wheels may work quite well indeed to detect movement here.