For this project, we created a dog that performs a magic trick. The trick is that the dog “eats” a yellow ribbon, magically transforms it into a green ribbon, and then spits out the green ribbon.
How it works:
We had two motors, one medium motor at the back that would wheel the yellow ribbon in and one regular motor in the front that would wheel the green ribbon out. We connected two gears to the back motor to turn an axle in which part of the yellow ribbon was already secured to. We programmed the back motor to move forward for 5 seconds (the gears would in turn actually make the axle move backwards) which would take in all of the yellow ribbon. Then the front motor, which is connected to a wheel wrapped with a green ribbon, would move forward, causing the green ribbon to move out. We covered the top with paper and feathers to hide the wheels and two different colored ribbons.
In order to fit the EV3 into our design, we used the back of the EV3 as support for the wheels, and created 4 legs to stand the EV3 up. This way, we condensed the amount of space we used while still maintaining access to the EV3. In order to make it easier on us, we connected the EV3 to the laptop to directly send the program to avoid lifting our mechanism.