To open the garage door we'll make a mechanism that transfers the rotation of our servo to the rotation of the door.

We could try to mount the door directly to the servo's shaft, but this would be a bit tricky, and pretty bulky looking.

Instead, we'll transfer the rotation of the servo over a short distance using a pushrod made from a paperclip.

Take a look at the diagrams below -- there are a few key things to note:

• The servo shaft rotates clockwise, and the servo arm rotates along with it
• The pushrod translates (moves) to the right and slightly down as it is pushed by the servo arm
• The pushrod pushes the door's control horn to the right
• The door is on a hinge (made from a drinking straw) which rotates counterclockwise around the door pivot dowel

Later in the guide, we'll build a similar mechanism for our garage.