Power Box Redo
Lesson in event driven software
Introduction
When old projects become flaky, it can be fun to bring them back to life. In doing so, you can introduce upgrades and most likely have to polish up the software sketch or dive into a total rewrite.
Project Description
I build a box that had a 12 and 24 volt power supply in it that I thought would be nice to control with an Arduino so I could set a trip point for the current and monitor the actual current and display all these things. I wanted to control everything from a keypad. This generated a lot of features so I listed all the things I had to include. It worked great for a long time.
Six years later I got the box out to see if it still worked and it had become flaky. The display had a bunch of crazy characters come on that obsured the commands and therefore ruined the project. So I decided to rework the project.
I quickly realized the LCD display was too complex with a parallel interface. Nowadays this can be done with an I2C bus. The keypad had too many buttons. In general, too many wires made the design a mess. Also, the software sketch was awkward. The hardware was easy to replace but the software really needed to be rethought.
So the project ended up being about the software and how best to write interrupt event driven and debugging code. I built a hardware simulation of the old box and wrote extensive comments that displayed on the serial monitor so I would know where I was in the code and if the functionality was working correctly. I think you might enjoy seeing how the code works and plays well for a project you might have in mind.