Final Project
About Color Pegs...
I set out to design an interactive toy that helps toddlers understand colors, shapes, and spatial relationships. In addition to teaching primary colors, I wanted to demonstrate secondary color principles as well, so I made the illuminated color splotch glow the appropriate secondary color any time two pegs were inserted into their corresponding holes.
The behind the scenes magic is pulled off by three hall effect sensors that relay signals to a single ATTiny44 microcontroller when they sense the magnetic field from a magenet embedded into the bottom (and top) of each peg. My code detects each of the 8 possible combinations and instructs the LED to illuminate the correct color!
Bill of Materials:
- 5/4 Maple – 9” x 13”
- 8/4 Maple – 3” x 10”- 3mm clear acrylic
- 3mm plywood
- 3x - Hall Effect sensors
- 1x RGB LED
- 1x - ATtiny44 microcontroller
- 2x - 1K resistors
- 1x - 499 resistor
- 1x - 10K resistor
- 1x - 1uf capacitor
- 1x – FTDI cable
- 1x – Red vinyl
- 1x – Yellow vinyl
- 1x – Blue vinyl
- 7x – #4 x 1/2" Round head wood screws
- 1x – #8 x 1/2" Countersink head wood screw
- 1x – #10-24 Countersink head machine screw
- 1x – #10-24 Machine nut
Licensing considerations:
I hope this project inspires you to make this or something like it for yourself. In fact, I have chosen a Creative Commons "Attribution-ShareAlike CC BY-SA" license for my design so you can do just that. This license lets you remix, tweak, and build upon my work even for commercial purposes, as long as you credit me and you license your new creations under the identical terms.
These links will allow you to learn more about the License Deed and the Legal Code .
An Important word about Safety!
If you do build this design for yourself, I strongly advise you to improve two things. I feel it is paramount that you do so if you even remotely think it will be used by a small child.
First and most importantly, design a better way to securely hold the magnets into the wooden blocks. My design uses simple vinyl stickers. This is not remotely robust enough to ensure that the magnets stay in place while a child plays with the toy. These small magnets not only pose a choking hazard, but can also cause internal damage and create life-threatening complications if more than one magnet is swallowed. A robust method of holding the magnets in place would include at least two mechanical restraints - for example epoxy to hold the magnet in a counterbored hole followed by a metal covering plate that is screwed into the wooden block. Please heed this warning!
Secondly, please consider a self contained power source. I'm using an FDTI cable which could pose a strangularion hazard for young children!
As a father of two boys, I take their safety more seriously than anything in this world. I urge you to consider the safety of those who might use your creations as well.
To learn more about how I build this project, check out my Final Project Development page.
Download my SolidWorks 2018 files
Download my SolidWorks PCB files
Download my Fabrication files for ShopBot, Laser Cutter, Roland Mill and Vinyl, 3D Printer