To make your Inchworm go, you need to attach the Circuit Playground Express board, the battery pack, and the servo to the cardboard body. And everything has to be connected with wires, without letting them get in the way of the moving parts. |
Peel-and-stick Velcro dots let you reposition or remove the CPX as needed. They also give you some clearance between the CPX board and the cardboard. That makes it easier to attach alligator clips to the board.
Just press one side of the Velcro onto the back of the board and the matching side on the front of the Inchworm.
In the example here, the hook (scratchy) side is attached to the CPX and the loop (soft) side is attached to the cardboard. |
Prep the Servo
Unlike a regular motor, a servo can only swing back and forth in a semi-circle, 180 degrees. But a servo is also self-aware -- it knows which direction it's facing. That means with a little coding, you can tell it where to turn!
To make the Inchworm crawl, you will program the servo to turn all the way towards the front, and then swing all the way towards the back, over and over. This motion pulls the front and back of the Inchworm together and then releases them, so the Inchworm moves slowly forward.
But before you attach the servo, you have to set it up so that the arm is facing in the right direction.
Hold the servo so the end with the wires is facing up when you are looking straight down at it. Press the one-armed horn (also called a half horn) onto the shaft of the motor so it is pointing to the right (three o'clock position).
This way the adhesive dot you use to attach the servo to the cardboard robot body will stick to the tape instead of the servo. It makes the servo easier to remove -- and also helps keep the servo firmly attached to the cardboard. |
Now that it's prepped and ready to go, you can attach the servo to the cardboard. Extra-strength adhesive dots are a simple way to glue the servo in place.
Press the glued side of the servo onto the cardboard with the wire end facing the front of the Inchworm.
When the Inchworm is standing up, the wires face up towards the top fold in the cardboard. |
Battery Holder Options
The battery holder contains your robot's On/Off switch. Make sure to attach the holder with the switch facing out! And position it so the wires face the CPX, since you have to plug them into the JST connector.
Tip: Keep in mind that the battery holder is the heaviest part on the Inchworm. You may want to try sticking it on with tape in different places and giving it a test run with all the electronics working before attaching it permanently.
If you have the battery holder with the belt clip, you can cut a slot in the cardboard and clip it right on. Be careful not to bend the cardboard as you insert it.
If there's no belt clip, use two or more adhesive dots to attach the battery holder to the cardboard. |