Before we began this project, we wanted to create something that could positively impact those often marginalized by the educational system. We came up with the idea for the Crimson Cube to hopefully merge our hardware experience with an impactful idea.

Our initial idea was to run all the inputs, outputs and WiFi module off of the NodeMCU microcontroller for simplicity. This was not possible upon the conclusion of the Hackathon due to issues outlined below.

Connecting to the internet to push to Firebase was done by utilizing the ESP8266WiFi library. The NodeMCU connected to a personal hotspot hosted by a laptop which allowed for a connection that only required an SSID and password. This was done as the existing networks in the area required an SSID as well as username and password.

As our design requirements included a time and date stamp for each input (which was required for effectively displaying information on the front end), we had to pull instantaneous time stamps. This was done through the NTPClient library. The ESP8266 would connect to the server and pull date and time information. A function was then written to pull time stamps whenever an input was activated.

We considered many different methods of uploading data from the Cube itself to the front end such as creating our own database through MySQL. However, we ended up using the FirebaseArduino library to call the Firebase API from the ESP8266 which simplified the process. This method also required the ArduinoJSON library as Firebase stores data in JSON format. The library allowed us to package each input with a time and date stamp into a JSON object which would then be pushed to Firebase.

Throughout the project there were many issues that occurred with the hardware. One of the largest issues was that we did not have an external power supply such as a battery for the NodeMCU or the Arduino. It was not feasible for us to bring one with us to the Hackathon due to airline regulations. Due to this, all the inputs, outputs and the WiFi module were run off the boards themselves. As expected, they were not able to power all these components simultaneously and the boards failed. In order to complete the Hackathon with a semi-complete project, we decided to split the inputs onto the Arduino inside the housing and the data transfer onto the NodeMCU. The Arduino separately handled inputs and outputted the relevant information on it's LEDs while the NodeMCU lived on a breadboard with buttons to demonstrate data transfer to the Firebase server.

Another issue we encountered was the limitations of the physical pins on the NodeMCU and Arduino. Due to the large amount of inputs and outputs we had, it was not possible to incorporate all elements of the project. In addition to this, the NodeMCU has many GPIO pins which have to be held in certain positions on either boot or throughout the program or else it will crash or get stuck in bootloader mode. This further reduced the available pins and made integrating all features very difficult.

A significant bug I encountered was errors outputted on the serial monitor due to the watchdog timer. At the time, I was unfamiliar with watchdogs and did not realize I was repeatedly triggering the hardware watchdog. This was due to implementing another members code which was not completely compatible with mine and creating an infinite loop. Eventually I solved the issue by eliminating the loop and was able to continue. These bugs were also littered around various compiler issues within the Arduino IDE which made them very challenging to pinpoint.

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