I am attempting a project that I would like to eventually work by itself without the need for an Arduino board. I have created the project as a standalone on a breadboard and tested it with power coming from the Arduino's 5v power line. (Nothing else is connected to the Arduino board apart from 5v power). With power coming from the Arduino everything works as expected. I then followed the instructions on the Arduino on a Breadboard page for creating a 5v regulated power supply, and my project did not work correctly: only input from one of the four buttons I was using was recognised. I measured the voltage from my power supply circuit and it read 5.1v, so I presumed that this was not the problem.
My project consists of four pushbuttons as inputs with an 8x8 LED matrix controlled by a MAX7219 IC as an output. I measured the current drawn from the entire project and it was around 0.5A. The input power source going to my 5v regulated power supply is from a 12v, 5A power adaptor.
Does anyone know why I am experiencing problems? Thanks in advance, Andrew