This week I completed planning the circuit/code and began the fabrication process.
To complete the circuit I needed to add the clear/restart and submit buttons. I then needed to adjust the Arduino and p5 interface codes to accept these inputs. I ended up creating a four element key code for myself to send serially. Each element within each byte describes the RFID reader, RFID card, clear/restart button state, and the submit button state, respectively. For example a serial reading of “0L00” would mean the letter “L” RFID card was scanned on reader 0 and none of the buttons were pressed. The Arduino and p5 codes can be found at these links. Figure 1 shows the breadboard circuit with the buttons attached.
Once this was complete, I moved on to fabrication. I began by planning the coin design. Figure 2 shows a test of the coin design. These coins were laser cut out of 1/8” plywood. Each coin consists of 4 wood pieces and is designed to conceal the RFID tag without gluing them inside the coins permanently. The top piece is a 2 inch diameter circle with the alphabet symbol engraved on one side. The next two layers are rings with an outer diameter of 2 inches and an inner diameter of 1.75 inches. These layers create a housing for the RFID tag to sit inside. Next another solid round layer closes the RFID tag inside the cavity. I plan to use wood glue to attach the top to the two middle rings. However, in order to access the RFID if something breaks, I plan to use strong adhesive or velcro to attach the tag to the wood and the wood bottom to the rest of the coin.
Once I came up with this design I checked that the thickness of the wood did not impair the RFID scanning (Figure 3).
Next I laser cut the entire visual alphabet (Figure 4).
Finally, I soldered the circuit onto a perfboard (Figure 5) and prepared the final design for the display panel (Figure 6).
This display directly took into account elements that were conveyed by individuals who completed my playtest. The headphones and monitor symbols were suggested to me during the playtest. In the coming week I need to complete the enclosure and coin fabrication and conduct user testing. Once the user testing is complete I will make any minor changes necessary to get a final product.