Here's a reel that is simple to make and requires few parts. - Margaret
Start with a motor.
I added two bricks to this clear motor and stood it on its
side.
You'll need these LEGO pieces
to make the reel.
The string for your reel will wind around the
yellow wheel. The two grey wheels help keep the string on the
wheel.
Cut a piece of string for your
reel. Thread one end through a hole in one of the grey wheels
and knot it securely.
Wind the string around the yellow
wheel a couple of times to get it started.
Next, attach the thing you plan
to reel in. I am going to make this zebra move.
Here's a program that I tried
with the reel. I set the power to 30 so it wouldn't move too
fast. This makes the zebra move forward just a little bit
at a time.