Clocks, I2C, Serial and You

I bought a bunch of parts awhile back with the good intention of building a bright, blue LED clock for my desk at work. Unfortunately, I got side tracked and the parts sat in my parts bin for a month or two. When I had a little too much caffeine in my system last weekend, I hit the parts box and built that clock. Needless to say it wasn’t as easy as it looked…

Parts List

  • 1x Arduino
  • 1x Sparkfun Serial 7-Segment Display
  • 1x Macetech Chronodot
  • 1x Solderless Breadboard


  • SFE Display Slave Select to Pin 10
  • SFE Display MOSI to 11
  • SFE Display MISO to 12
  • SFE Display SCK to 13
  • SFE Display VCC to 5v
  • SFE Display GND to GND
  • Chronodot SDA to Arduino Pin 4
  • Chronodot SCL to Arduino Pin 5
  • Chronodot VCC to 5v
  • Chronodot GND to GND


The code below is a modified version of the Chronodot demo code. If you uncomment the set_time() call, it will set the time to the HH:MM passed to the function.


About Willa

Infosec princess with a penchant for secure coding, hacker, mother of one, and wife of @nifty_ba.