Return To Build


Basic Mechanisms


Cable System

Steps 1 2 3 4 5 6 7 8 9 10 11 12 13

Step 1

The cable system transfers the servo’s circular movement to a bending movement.

Popular uses of the cable system include bending necks and wiggling fingers. What will you create?

Step 2


  • Hummingbird Controller (Bit Controller pictured. The Duo controller will also work)
  • Battery Pack or AC Plug Position
  • Servo (Your servo may look different)
  • X Servo Horn

Suggested Craft Supplies

  • Hot Glue Gun
  • Heavy Duty Hole Punch
  • Scissors
  • Blade
  • Marker
  • String (About 40 cm)
  • Drinking Straw
  • Scrap Cardboard
  • Cardboard Box with Flaps (For beginners, we have found the 6x6x6 box works best)
Step 3

Double knot the end of the string to the servo horn.

Step 4

From the scrap cardboard, cut a strip of cardboard. This one is roughly 16cm by 4cm. Your cardboard strip can be a little larger or a little smaller to accommodate your design. 

Step 5

Fold the strip of cardboard into 4 equal sections.

Step 6

Cut 3 small pieces from the straw. Each piece should be about 3 cm long.

Step 7

Hot glue the the 3 pieces of the straw to 3 sections of the cardboard strip.

Step 8

Punch a hole in the bottom section of the cardboard strip. The hole should be close to the crease.

Make 2 small cuts (about 1 cm in length) along the top left and top right of the cardboard strip

Step 9

Feed the string though the hole in the bottom section of the cardboard, then through each of the straws.

Step 10

Interlock the tabs on both sides of the box.

Step 11

Place the position servo near the edge of the box. Trace around the servo, then cut out the rectangle. Be sure to cut on the inside of the line so that the servo has a snug fit.

Step 12

Feed the wire into the box, then push the base of the servo through the hole until it is secure. If the hole was cut too large, a dab of hot glue may help to keep the servo in place.

Step 13

Glue the bottom section of the cardboard to the top of the box. The hole in the base of the cardboard strip should be in line with the servo shaft.

Push the servo horn onto the servo shaft. Pull the string until taut, and then wrap the sting around the top of the cardboard strip so that the string fits into the cuts on the left and right sides of the cardboard. Lock the string into place by fitting it through the cut on the the top section of the cardboard.

Need help getting started? Select your desired programming language and device from this page.