Before actually drawing the circuit, first we need to understand the properties and functions of all the blocks.
The properties of different function blocks：
Autodesk Tinkercad Circuit have been used in designing and testing the circuit.
Fig. 1. Designing a "Syllable-Block" circuit(top) and a "Start-Block" circuit(bottom) using Tinkercad
2.1.2 Prototyping and Testing
The designed circuit were then build with an actual Arduino board. The code were also uploaded to it for testing and debugging. In the design, each blocks will be connected with three pins: two signal pins and one ground(GND) pin.
Fig. 2. A functional "Syllable-Block" circuit
Several more circuit prototype have been made for testing the connection between two or more blocks.
Fig. 3. Two functional "Syllable-Block" circuits being connected
2.1.3 Finalized Circuit Design
After going through designing, testing and debugging process, the circuit for all the blocks were finalized.
(Click below to view large image)
2.1.4 Circuit Shrinkage
The circuit prototype above is too large to be an actual playable building block for children. The size of the Arduino board and the breadboard are too big, and the circuit need to be self-contained without any USB wire connecting to computer. As this toolkit is targeting to children and younger age, their hand size also needed to be consider. It seems to be an acceptable size that each building block should be smaller or equal to the size of a standard Rubik's cube.
With the above components, the circuit were rebuild and the size has been decrease for around 50%.
Fig. 5. Original circuit prototype(top), and resized circuit(bottom)
Since this toolkit is designed for BVI students, every building blocks have to be easily connected without the help of vision. Therefore, I came up with an idea of using magnet and conductive tapes to build the connection. By doing so, the blocks can be easily snap with each other and the signal can also be transmitted.
Fig. 7. Two wooden boxes and with a simple circuit have been made for testing different conductive tape
The result suggested that conductive fiber could be a better choice in connecting the circuit between two building blocks.
Fig. 8. Test result for copper tape(left) and conductive fiber tape(right)