In a previous serie of articles I showed you my progress in writing a Arduino Due driver for the Adafruit 16×32 LED matrix. Last few days I’ve focussed more on adding support for a simple font and displaying text characters, but actually during this implementation I discovered the solution behind 2 programming mistakes that were still left in the driver code. With this solved, I starting thinking about how to implement a font. After thinking of my own way of implementing this I also looked at how it was done in the original driver for Arduino Uno and actually some of the ideas matched. So I could really easy copy, adjust and implement the code for displaying characters, displaying ‘HELLO’ is now a matter of writing 6 lines of code!
After this I implemented code for reading a I2C compatible ADT7410 temperature sensor and use it for displaying the room temperature. Next I included and implemented code I’d already written before which allowed me to use the Adafruit C3300 (Wifi / SD) shield. The code connects the Arduino to the local WLAN and do NTP request to synchronize a software made clock with the internet. Furthermore it can also read and write data from/to an SD card. The SD card is used to hold the WLAN settings, it does this at boot time and it is only milliseconds later when it will use this data to configure and make the WiFi connection to you LAN. Voila, altogether there we have it: an Arduino based self synchronizing clock!