Santa's Sorting Hat




Introduction: Santa's Sorting Hat

About: I used to teach middle school science, but now I run my own online educational science website. I spend my days designing new projects for students and Makers to put together.

We've been working closely with Santa's Workshop to bring you this innovation in naughty or nice list communication. Now, you can check in real-time if your good and bad deeds have affected your standing on Santa's Naughty or Nice list! A fun project to make and share with your friends who's results may surprise you!

Over the holidays we created this cute shorting hat for a workshop we attended. The hat consists of a servo, Arduino, and a pushbutton and is powered by a USB Power Bank. It's a pretty simple build overall and a real big hit with kids of all ages.

This project could easily be adapted for other events or expanded on to animate a Harry Potter Sorting Hat, add in sound effects, or even mp3 sound effects via a cheap mp3 playback module.

If you like our projects and want to see more check us out on instagram, twitter, facebook, and or youtube!


    Brown Dog Gadgets does in fact sell kits and supplies, however you can most certainly build this project without buying a single thing from us. Though buying from us does help support small our small business and us building cool projects just like this.

    Electronics Needed:

    Craft Supplies Needed

    • LEGO Technics piece that fits over the Servo's LEGO axel horn
    • Popsicle Stick
    • Twine
    • Zip Ties (smallest size)
    • 1/4 inch EVA Foam
    • Craft Foam
    • Paper, and embellishments to decorate
    • A Santa Hat, or Fleece and a sewing machine to make your own
    • A Big White PomPom, Star, or other hat toppers

    Optional: A Silhouette or Cricut electronic cutting machine to cut out the design

    Teacher Notes

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    Step 1: Cut Strips of 1/4 Inch EVA/Craft Foam

    We first measured our heads and came up with some average measurements. You may want to tweak these depending on your head sizes.

    Cut strips of 1/4 inch EVA/Craft foam to these measurements:

    • 1.25 in x the Circumference of the head
    • 1.25 in x Over the top of the head front to back
    • 1.25 in x Over the top of the head side to side

    Attach the pieces with duct tape to make the structure as shown in the drawing. You may also use rubber cement.

    Step 2: Attach the Motor

      Since our LEGO compatible servo has flat edges and also some large holes it was very easy to tie it down. Other servos can be attached with glue or even strong foam tape.

      Attach the motor to the top of the structure by threading twine thought the foam, around the motor, and back thought the foam.

      Tie a big knot on each side to secure as shown.

      Step 3: Attach the Board

        The Crazy Circuits Robotics Board is designed to stick on LEGOs, which is why it has so many large holes on it. We took advantage of this to help us tie this down. If you're going to use a different Arduino board make sure you secure it down properly as to not cause shorts or breaks.

        Attach the Crazy Circuits board to the back of the structure using twine.

        Thread the twine through the holes in the Crazy Circuits board and tie a knot as shown.

        Step 4: Connect the Button

        The button will trigger the hat to make a Naughty or Nice decision when placed on a new wearer's head. :)

        Using conductive thread, connect the D9 pin to the positive pin of the button.

        Using a new piece of conductive thread, connect the ground pin to the ground pin of the button. Alternatively you could also use conductive tape, such as Maker Tape, to connect the Robotics Board to the pushbutton.

        Tip: Use a small piece of tape to hold the button in place while you sew. Trim any stray threads and use clear nail polish to set the thread once you've checked that it works.

        Use twine to tie the button to the inside of the hat structure with twine through holes D11 and D12.

        Step 5: Connect the Motor to the Board

          The reason we're using the Robotics Board is because of it's size, holes to help us tie things down, and built in pin headers to easily connect our servo.

          Connect the Servo to D3 as shown. You can wind the wire around the structure a few times first so that it takes up the slack.

          Step 6: Connect the Popsicle Stick to the Lego Arm

            Align the LEGO piece so that the "+" shaped motor connector hole sticks out beyond the stick, and mark two spots for holes to secure it.

            Drill two holes in the popsicle stick

            Secure the Lego piece to stick with zip ties.

            Trim the zip ties (not pictured)

            Step 7: Upload the Code

            Our Arduino code is extremely basic, feel free to change it if you want.

            Download, or copy and paste the code into the Arduino IDE.

            Upload the code to your Crazy Circuits board.

            If this is your first time using the Crazy Circuits Robotics Board, review this setup guide.

            Connect the LEGO piece to the top of the motor.

            Use a protractor to check the angle, and adjust the code if you'd like to change its behavior.

            Once you've set the "up" position, use a marker to mark the motorhead so that if the arm comes off you can put it back on in the correct position.

            Step 8: Make the Outer Ring

              Cut another piece of foam that is 3 in wide and as long as needed to wrap around the hat structure.

              Make or buy a Santa hat.

              Place the Santa hat over the new outer ring.

                Step 9: Power It Up!

                  We're just using a random USB power bank that we bought off amazon because it fit well in the hat. If you wanted to you could use a 3AA or AAA battery holder and connect it to the Robotics Board.

                  Plug in the USB battery pack.

                  Tuck the Santa hat around the edge of the outer ring. Insert the hat structure inside.

                  Insert the popsicle stick through the top of the hat, or otherwise secure it a the top.

                  You can choose to embellish the pom-pom, make it look like an arrow, or create a design that you like.

                  Step 10: Cut the File and Wear!

                    We designed a really cute "Naughty Or Nice" graphic which we cut out of craft foam. You could also use a Cameo Silhouette or laser cutter to make something as well. We've included a PDF of our vector design in case you want to print it off or machine cut it out.

                    Download and cut out the "Naughty or Nice?" template out of paper, craft foam, or any material that you like.

                    Use hot-glue to attach it to the front of the hat.

                    Then you're done! It's time to see which of your friends are naughty and which are nice!

                    To reiterate, it would be externally easy to turn this hat into something bigger and better using this basic design. Especially for Halloween. If you have some fun ideas please share them in the comments below!

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                      5 Discussions


                      26 days ago

                      I have to ask is it programmed for specific results or completely random.


                      4 weeks ago

                      We're going to try and expand this project into a Harry Potter sorting hat later this year. It would make for a nice halloween activity.


                      Reply 27 days ago

                      That will be amazing! I love this one too, it's so adorable!

                      Penolopy Bulnick
                      Penolopy Bulnick

                      4 weeks ago

                      This is just the cutest and it looks like the kids are just having so much fun!!!


                      4 weeks ago

                      The looks on their faces as they wait to know if they're naughty or nice had me cracking up. What a fun project! :D