Once upon a time, actually I don’t know the time because I don’t have a working alarm clock. I decided to take apart my own alarm clock to get a glimpse of the inside components and tinker around with it.
The idea is to make a new alarm clock with an Arduino and a WiFi or Bluetooth module that I can control with my smartphone. I took the led display out of the alarm clock and I hoped that it would connect easily to a breadboard and Arduino. But because it came out of a old alarm clock I need to build a my own interface with shift registers and a multi/demulitiplexer.
As you can see I attached the led display to a breadboard, this was for testing purposes to see if I could get it working on a breadboard. I’ll probably use some code and electrical design from this blog post as an reference to this project. Hopefully in a couple of weeks I got a working alarm clock again.
While searching on the internet I found a LED display driver chip, the MAX7219CNG. Because the led display is common cathode display, this should work together, and it saves me the hassle of thinkering with a demultiplexer.