Fun PaperCraft! 

Get creative and turn this project into a playful creation with colorful paper cutouts. Papercraft is an art form that uses paper as a medium to create three dimensional objects. Here we made Blink The Python Snake move with the help of a micro-servo and Circuit Playground Express.

Electronic Parts

We'll be using the Adafruit Circuit Playground to control a micro servo and power our project using a 3x AAA battery pack. This is all we need to create simple movements. But thats not all! Circuit Playground Express has tons of sensors (like accelerometer, light, sound and temperature sensors) to experiment with, not to mention the radiant glow of 10x NeoPixels!

Tools & Supplies

Assortment of materials and hand tools to work with.  

• Cardboard – 8.5x11 (2.6mm)
• Office paper – 8.5x11 
• Cutting Mat
• Ruler / T-Square
• Scissors
• X-Acto Knife
• 3x AAA Batteries

The enclosure is similar to cases that are designed to be made on a laser cutter. This design doesn't require screws or glue because of the tight tolerances in slots. Cardboard has a bit of flex so it can compress and fit through tight openings. The tabs extend beyond the slots to accommodate for slop during the cutting process. 

Paper Template

We designed the enclosure to be made out of cardboard. This is the type of cardboard most commonly used by UPS shipping boxes. It's around 2.6mm thick. If you're using a material that is thinner or thicker, it might not fit perfectly when assembling. The tabs and slots are designed for ~2.6mm clearances.

Cutting Parts

The template can be printed with an office/home inkjet printer. This can then be transferred to cardboard by cutting each part out and tracing it with a marker or sticking it to the surface. Either way, you can cut it out by hand or use a vinyl cutter like a Cricut or Silhouette.

Explode Wireframe

This animated GIF showcases the assembly of the case. Here's how the pieces fit together. Start with the left wall and insert the tabs from the three non-slotted parts. Then, insert the longer part to the bottom. Fit the remaining tabs into the slots of the right wall to hold everything together.

Along The Grain

When cutting the left and right pieces, it's important to orient the paper template so the corrugations are going along the length of the sides. This way the cardboard is a bit stronger and less likely to bend when cutting and handling. 

Making Cutouts

The slots and cutouts for the tabs and components can be a little tricky. I found it easier to freehand cut than using a ruler. Slowly insert the tip of the blade and cut in a reciprocating manner. Doing this several times will cut through the internal corrugations. Flip the part over and follow the cut by slightly scoring the outline.  

Mount Holes

The Circuit Playground Express board can be secured to this cardboard piece using M3 sized standoffs, screws and hex nuts. To make the holes I used a Dremel rotary tool with a 1/8in drill bit. You could also use a hand awl (commonly used for making holes in fabric when sewing or stitching).

Install Standoffs

These M3 female/male brass standoffs are 10mm in height. I got a variety pack from amazon. These have a threaded hole on one side and a male threaded end on the other. Insert the male end into the cardboard and fasten a hex nut to secure it in place. Repeat this process for all four mounting holes.

Secure CPX

Place the CPX over the four standoffs and orient the PCB so the mounting holes line up. Depending on your project, you'll want to orient the board so it's easy to access the JST and USB ports for connectivity. In my case I had the ports facing "right-side up". Insert and fasten 4x M3 machine screws through the top of the CPX going into the brass standoffs.  

Install Micro Servo

Start by inserting the cable from the micro servo into the cutout. Then, carefully press the body of the servo through. It should have a tight fitting. Using the two mounting screws that came with the micro servo, insert and fasten them to secure the servo.

Alligator Clips

Before we assemble the rest of the case, we'll need to hook up the wires. Connect three mini alligator clips to VOUT, A1 and GND labeled pads on the Circuit Playground Express board. Grab the male jumper connectors and thread them through the bottom cutout in the center of the CPX. This will make it easier to connect the micro servo to the mini alligator clips.

Connect Micro Servo

Grab the male jumper cables from the alligator clips and connect them to the female jumper cables on the micro servo. Make sure the connections are correct. Yellow (siginal) to A1, Blue (ground) to GND, and red(voltage) to VOUT. Double check these connections are correct.

Box Assembly

Start with one of the side pieces and the bottom piece. Insert the tabs into the slots and hold them together in place. While holding assembly in one hand, place the servo piece over in the center. Orient the piece so the tabs can insert into both the slots of the bottom and side pieces. Grab the cpx piece and insert the the tabs into the slot. Now the opposite side piece can be installed by fitting the tabs into the slots. Keep the orientation consistent with the opposite piece. Finally insert the last piece into the left and right sides.

Install Battery

Start by inserting the JST connector from the battery pack through the notch near the bottom piece. Thread the cable through the piece and connect it to the JST port on the  Circuit Playground Express. Press the battery through the side piece and push it through the opening in the opposite piece. To keep the wiring inside, fold the wire into a bundle and secure with a twisty tie.

Servo Movements

Micro servos come with a few different servo horns that can be used to attach to stuff. In our demo, we constructed a paper crafted version of Blinka. Using a piece of cardboard, you can secure the servo horn using included screws. The piece of cardboard can be glued to the lower back of Blinka.