Arduino LED Matrix Clock

thingiverse

This is a straightforward Desk Clock constructed from five 8x8 LED matrices and an Arduino Nano / Pro Mini. The clock utilizes a DS3231 RTC IC, which not only provides highly accurate timekeeping but also delivers a temperature reading. Although the accuracy of this feature may be slightly compromised, it serves its purpose well. To switch between normal Time-Display and Date / Temperature Reading modes, users can employ a touch sensor (TTP223) or button. The matrices (powered by MAX7219 driver), RTC, and touch sensor are readily available for purchase on e-Bay or Aliexpress. Unfortunately, the LEDs and their driver chip tend to generate excessive heat, rendering it impractical to obtain an accurate temperature reading of the environment. In response, I opted for a DHT11 sensor located at a distance from the clock's core components, connected via one of the former data lines in an old USB cable. This setup allows for effective communication with the sensor, and since I²C communication employs two wires, it would be feasible to position the RTC at the end of the cable as well. To incorporate the heat-spreader of an old Intel Pentium 4 as a touch button on top, I utilized its large metal surface area. This increased trigger distance significantly, rendering wall-mounting the clock impossible. Fortunately, the sensitivity of the touch-sensor can be adjusted to suit individual preferences (see last image). In addition to the provided 3D-printable model, I have uploaded the necessary Arduino-Code on GitHub: https://github.com/wilhelmzeuschner/arduino_led_matrix_clock. If you decide to build this project and would like to express your gratitude, I'd be more than happy to see a post in the "Makes" section.