A STEM Project: Using a Brown Dog Bit Board With A Microbit to Oscillate a Bow Tie on a Clown

A clown is a fun character to see at the Circus. In this blog posting, I make a circus clown with a movable bow tie, the clown's red nose blinks on and off. A message saying "Welcome to the Circus" is streamed across the LED display. The clown's bow tie oscillates back and forth when button A is pressed on the Microbit. When button B is pressed, the Microbit plays a song called "Entry of the Gladiators, a Thunder and Blazes March" by Julius Fucik, 1872 - 1916. When button A and B are pressed simultaneously, the clown's bow tie stops and goes back to its equilibrium position.

Here is a video of the Microbit in action.

The Microbit has a limited power supply of 3 volts. Motors that are powered by the Microbit, do not run well or not at all because of the limited power draw. I used a Brown Dog Crazy Circuits Bit Board. https://www.browndoggadgets.com/products/crazy-circuits-bit-board to expand the capabilities of my Microbit to use a 270 degree servo https://www.browndoggadgets.com/collections/crazy-circuits-kits-and-parts/products/brick-compatible-270-degree-servo

I made a paper box to contain the components necessary to operate this project. I made my box using a Silhouette Cameo, an electronic paper cutting machine.  I have included three different files where you can make this box.

You can print and cut the box and clown with scissors or use the files for an electronic paper cutter. I used 65 lb. white cardstock and Glue Dots for the design.  Here is the PDF. 

https://drive.google.com/file/d/1d8aqxi0_Ae8tVBtsLYb9M364WhA6dyet/view?usp=sharing 

Here is the .Studio file for a Silhouette cutting machine.

https://drive.google.com/file/d/1cxfqwBTAAvZvQsjJAOLAxb0lmttA7UZ3/view?usp=sharing

Here is the SVG for all other electronic cutting machines. I included a one inch square for reference.

https://drive.google.com/file/d/178PdETNbiDD28s2HuZ55q0SdjduZuq_c/view?usp=sharing

 

Make the Paper Box  

Half of the paper box has been made in the photo above.  

There is a structural beam that is added to the corners in the front of the box.  This is necessary to add more support to this area. The support is a beam with diagonal in the center.  To make this beam, glue is placed on three tabs as shown above and folded inward to adhere the glue. The sides of box are glued so that there is a slight gap at the bottom of the box to accommodate the  Brown Dog Bit Board.

Add a Glue Dot to the back of the battery pack.

Adhere the battery pack to the back of the box on the left side. Two Lego pieces are needed for the 270 degree Servo - I used 2 - 1 x 4 Lego pieces. 

The Microbit has been inserted onto the Brown Dog Bit Board. 

Attach the Lego pieces to the Servo and apply a Glue Dot to the center of the 1 x 4 Lego piece as shown above (the Glue Dots are clear but you can see them glisten a bit in the photo). Attach the servo to Pin 13. Set this aside.

Make the LED Light Assembly

Using a red LED light, (please note, the longer wire is positive), I made a holder for this LED light by using the following instructions in this YouTube video.  https://youtu.be/jmsu__UYTl8?si=dS8hfbSRW0h7QUfb 

Once the LED holder was made, I used two alligator clips; a yellow alligator clip was used for connecting the positive side of the light to pin 0 at the bottom of the Microbit .

A blue alligator clip was used for the connecting the ground side of the light to pin GND at the bottom of the Microbit. 

Insert the Bit Board into the Paper Box 

Insert the Brown Dog Bit Board into the paper box. Attach the Microbit by sliding the paper side tabs over the Microbit's buttons A and B.

Attach the servo to the paper box by adhering the Glue Dots that were previously attached to the 1 x 4  Lego pieces.

Attach the LED light in the other hole.

Program The Microbit

Here is the program that I used to operate my Microbit,

https://makecode.microbit.org/S39612-60287-56746-17009

The program does a few things.  It streams the message "Welcome to the Circus" across the LED display. When the left button is pressed, the bow tie moves back and forth. When the right button is pressed, the circus song is played. When both the left and right buttons are pressed, the bow tie stops its movement and goes to its center point.

Download the program to the Microbit.

Attach the battery wire to the Brown Dog Bit Board.  

(It is the red connector with the red and black wires that is slid into the two red squares on the bit board.)

Embellish the clown face and align the two holes on the face to the two holes on the box.

Place a Glue Dot on the tip of the servo shaft.

Attach the bow tie to this Glue Dot.

There is a door at the back of the paper box for easy accessibility to the battery.  The Servo and the LED light does not need to be disconnected to power on/off this project.