This Project is meant for Boy Scouts.

lots of 9-volt batteries

This is an easy community service project that can help get your troop more well-known in your town. You should check with your local fire/police department to see if you can cooperate with them.

Acquire a supply of 9-volt batteries, either purchased or donated from a local hardware store.

Send scouts into local neighborhoods, working in teams of 3, offering to check smoke detectors and replace batteries as needed.

Having a flyer to hand out to residents about the need to periodically check detectors is a good idea, even better if it is on fire department letterhead.