Fun questions 
the project is to take mechanical energy and convert it to electrical energy.
we will have a generator on top of the bag which goes to a powerbank which will power the arduino. (we got some tips from our teacher how to charge and discharge at the same time because that is prob the hardest part)
further we are going to get the arduino and all other components to the bottom of the bag and glue them or screw we are not sure yet and give them some cover of protection, and the powerbank prob will go there to. after all that we will make like a tiny door (can't figure the correct english word) so the powerbank will be easily accesseble to put in a charger if our generator will not give enough power, because we haven't learned yet how to calc how much the generator can deliver.
overall quite a fun project just pretty difficult if you're doing everything for the 1st or 2nd time.