Electrical Connections

Use the assembly instructions for attaching the Circuit Playground Express to the Crickit.

The servo plugs into the Crickit board in the block of pins marked Servo at the first spot marked 1. The lightest color (yellow/orange) connects to the signal pin near the board edge. The connector side with the black wire faces the center of the board.

For the DC motor, use alligator clips to the motor wires, connect the pin ends to the Motor 2 pins (the ground and Motor 1 pins are unused). The clips will connect to the motor connection wires. If you ever find the fan running backwards, power off the project and swap the alligator connections which will reverse the direction of the motor.

The Wand

If you have very long bubble wand handles, you may need to trim them. About 8 cm / 3" works well but you'll want to check the mechanics of your setup to ensure things will work.

Select a servo horn from the package that comes with the servo. I used the X shaped horn but the double inline one is fine. The wand will be connected to the servo horn using the long pointy screws that come with the servo.

Drill two holes using a tiny drill bit that matches holes in the horn. Take the horn and using a short screw, connect the horn to the servo.

Screw the wand onto the horn.  Alternatively you can try to hot glue or super glue the wand onto the horn. Gluing will not allow removal of the wand and since the wand covers the horn attachment screw, the horn is permanently attached. Screws would be best.

Attach the horn to the servo body with the short screw provided. If you use the longer screw it might damage the servo. The longer screws are used to attach items like the wand to the horn.
The wand screwed onto the horn and flat top Lego pieces glued onto the motor mounts.

Mounting the Motor and Servo

I chose Lego to build mounts for this project. It allowed for positioning both the servo and the fan motor in many different ways to find the best configuration.

To make the DC motor Lego compatible, I super glued two pieces, one 2x1, another 2x2 - both with flat heads. For the Servo, I used two 2x2 flat head pieces. If you do not have these pieces in your Lego box, they can be obtained from https://shop.lego.com. If you need additional "standard" pieces to mount the motor and fan, plan on picking those pieces up at the same time.

Super glue two 2x2 tiles onto the servo and one each 2x2 and 2x1 onto the DC Motor Mount. Allow to dry.

You can now snap the DC motor into the motor holder and press on the fan blades.

Your Bubble Container

Your container with all the bubble solution in it should preferably be square and deep:

  • A bit deeper than the diameter of the bubble wand so the servo can fully dunk the wand into the solution and coat the surface. Less than a full dunk does not guarantee the wand has the full amount of solution to produce bubbles.
  • Square helps fit against the base of the servo. When the wand is moved by the servo up and down, you need to ensure the wand does not hit any part of the bubble mixture container, bottom or sides.

Leftover food containers and takeout containers might work. The one below came as a craft container from Michaels.

Check your plastic container selection for a somewhat deep rectangular or square container, a bit deeper than the diameter of your bubble wand.

This guide was first published on Aug 22, 2018. It was last updated on Aug 22, 2018.

This page (Sub-Assemblies) was last updated on Aug 16, 2018.

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