I ordered robot charms from Beads Labels Etsy shop (Hong Kong). Great shop, the charms arrived in just over a week. There are a number of metal robot charms available on Etsy, but very limited in the way of plastic charms.
I picked up some plastic lace, springs, pony beads, and key fobs at my local beading store and got to work with 17 kids aged 4 and 5. The kids were able to do this project themselves and only required an adult to finish off the hardware.
Here's a little collage of just *some* of the backpacks
1. Cut a piece of plastic lace about 20 cm long (you decide how long you want your pull) (20 cm will be end up being about a 7 cm pull)
2. Thread the robot charm to the middle of the lace
3. Now thread the spring through both pieces of lace it will rest on the robot
4. Thread assorted pony beads and leave about 3 cm at the top
5. Double tie the pull to the metal fob and tuck the ends back under the pony beads.
6. Attach to your zipper and admire.
Other posts in this series include the Robot Tunic and Robot Garland
This post is linked to Someday Crafts Back to School Idea Share