Introduction: Shake to Decide

I created a decision making machine that spins a light around the disc when shaken, finally landing on one choice. Different ways you might use this could be to decide what meal to cook, what activity to do to cure boredom, or even what workout to do for the day. Follow along to see how I made it!


  • Circuit Playground Express controller
  • 3 AAA batteries
  • AAA battery pack
  • Laptop
  • Wooden panel (mine is 6x6")
  • Felt
  • Embroidery thread
  • Glue
  • Scissors
  • Card stock or thick paper
  • Acrylic paint and brush
  • Masking tape
  • Ruler
  • Pencil

Step 1: Program Your Microcontroller

Use Adafruit to program the disc so that a single white photon light circles the border at decreasing speed until it finally lands on a single light. This tutorial was helpful for me to understand how to program the wheel response to a hard shake. The main tools to understand for this program are the two variables, "time" and "delay." To customize the length and speed of the cycle, change the numbers of these two variables to suit your preference for speed and time.

I skipped steps 7 and 8 and went straight to step 9, because I did not want the controller to make any sounds until it lands on the final choice. I also decided that the board would only respond to an 8g shake, making it harder to accidentally trigger the response. In photon set pen hue, I eventually decided on changing it to "pick random number between 0 and 255," so that the color would be different on every shake.

Step 2: Create Your Cover

For my project, I didn't want the circuit board to show, so I cut out a paper cover for it.

On the back of your paper, trace your microcontroller and mark out the placement of the lights. Use a sharp tool like a pin or an awl to poke pinholes for the light to shine through. Use the tip of a pencil to widen the holes in necessary.

Cut out a strip of paper 6" in length and 1/4" in width. Rap this around the edge of your disk, applying tape on the inside, without covering the holes. Use the scissors to cut a small space for your chord to go through. Now, you should be able to slip the cover right over the controller.

Step 3: Sew a Pocket for the Battery Pack

I used felt for my pocket, but most fabrics would work for this.

To measure, I wrapped the felt around my battery pack and cut myself some extra material to trim later. I folded the felt in half and stitched two sides closed, leaving one open to slide the battery pack in and out. I attached it to the back of the panel using fabric glue.

In the future, I might chose to reattach this using velcro instead, so it can come off with the battery pack.

Step 4: Attach the Controller

Identify the center of the board by drawing lines with a ruler from corner to corner. Use tape to secure the circuit board to the panel, making sure none of the LEDs are covered. Attach the battery pack to the circuit board and put it in its pocket on the back. Tape down the chord so it will not move around. Next, fit your paper cover over circuit, and join it to the board around the edges with tape.

Step 5: Sketch Out Your Cover

Measure your board and cut a piece of multimedia or bristol paper the same size. Cut out a circle in the center, so the paper can slip over the controller cover.

Use a ruler to mark out the lines that radiate from the lights in the center towards the edge of the panel. Then draw lines between each of these markings all the way to the edge, so that each light corresponds with a wedge.

Decide how many different colors you want to paint your "wheel". I decided I wanted three colors total, so I marked the wedges with 1, 2, and 3 to key me colors for later.

Note: there are two gaps in the controller where there are no lights, so I used these extra wedges as a place to label the purpose of the device.

Step 6: Paint Your Design

Remove the paper from the top of your board before painting. Use masking tape to mask off the lines around the wedges you are painting first.

Pay attention to the drying time of your acrylic paint, and make sure to wait the full time before taping over an area you have painted already. I made the mistake of taping one of the sections too soon, and when I removed the tape, it pulled off some of the paint with it.

Step 7: Label Your Wedges

Now it is time to decide what to decide! If, for example, you want your spinner to tell you what to cook for dinner, write the name of a different meal in each wedge, excluding the two wedges that do not correspond to lights.

I chose to attach my final design with velcro so I would have the option to change with other labels to fit different scenarios.

Attach your design to the board, lining it up so the labels match to the lights.

Step 8: Give It a Shake!

Turn on the battery pack and give the board a hard shake to decide your fate!