After we got our idea to work from, we made the claw with a turning table on it to grab the spools. After this, we made a an elevator to elevate that claw. Once that was done, we made the base to hold everything. The biggest problem we've faced was to build a claw that would have a tight grab on the spool. Another problem was the batteries, we had to much power needed for them. But, at the end, both were solved.