i will show you how to make a generator easily.for this you will need common and cheap things.ihave given drawn pictures instead of real picture. so it may noybe so clear.with this generator you may not produce that much energy but still it may generate enough electricity to light up a led bulb.
you will need the following things:
1)an iron nail of 15-20 cm.
2)a card board sheet.
3)a strong magnet.
4)copper wire of 28-30 gauge.