The Arduino Pro Mini will be selected as the controller due to its small size and reliability. This micro controller is small. I ordered 2 of them from Sparkfun and they arrived in a few days. They don’t come with header pins installed. This is a plus because I have the option to header or wire it in a way the is dictated by the design.
Here is a pin out map of the Arduino Pro Mini for reference.
I had some reservations about how to power the controller. I wasn’t sure if the micro controller came with a voltage regulator or not. Turns out it did. The RAW supply voltage can be 3.3Vdc to 12Vdc for my 3.3V boards. The 5V boards use a range from 5-12 instead. There is voltage input pin from a regulated supply. This could be handy if I need to use a more efficient regulator or use an external regulator to supply more peripherals.
Programing the board was another area of uncertainty. The micro controller doesn’t have a USB connection, so I had to use the FTDI Basic Breakout from Sparkfun. It turned out to be easier than I thought. The pin out connection with the micro controller is outlined here in this diagram:
The controller will need to be protected from the elements. Accessibility to the programing port will need to be considered. This will allow system improvements through firmware updates. The controller should be programmed to use the least amount of power possible.