We designed these 2x3 dividers to be cut out of chipboard material. Our SVG files can be used on a laser cutter, cutting machine (like Cricut or Silhouette) or even 3D printed. Use a medium weight chipboard, it's about 1.6mm thick.
If you use a different material, make sure to measure the thickness. You may need to update the "slits" in the dividers to accommodate the materials thickness. The slits should be the same size as the material.
The bottom of the lunchbox is lined with a chipboard cutout that covers up the bottom. This helps keep the lunchbox clean in case things spill over. We used the same material as the dividers. You can also cutout the design out of foil card stock or patterned scrapbooking paper.
A NeoPixel strip can be lined along the inside of the lunchbox. Place the strip down with the LEDs facing inwards. Spread the strip so it's right up against the walls of the lunchbox. The strip is insulated with a silicone sheathing that proves grip so it holds together.
Use a bit of mounting tack to stick the circuit playground onto the inside of the cover. It looks great in the center of adabot's chest.