This is a pretty big project. Yes, get an arduino MEGA 2560 R3 for this job.
So far, this is a very minimal project. any of the basic units could work.
Start with a piece of paper or Excel.
- How many analog inputs
- How many digital inputs
- How many digital outputs
- How many digital outputs requiring drivers (relays, FETs, etc.)
- What kind of display? How many outputs are required?
- How many voltages? 5V, 3.3V, others?
Then you have an idea of whether you are talking about an UNO or a Mega. Personally, if I do not know what I really want to do, I design on a Mega and par-down later to a 328 (mini, UNO, naked board) if possible. The UNO only has 2K of SRAM and the Mega2560 has 8K and that along can be a show-stopper if you need large arrays in SRAM. Static Arrays can be placed in flash for look-up tables with just a small performance hit... they require space in the "code' area.
read this: Arduino Memories | Memories of an Arduino | Adafruit Learning System
Whatever you do, please consider a authentic Arduino as your first one because it is far easier to get help from this forum as most folks have a UNO or a Mega2560. When you go off and get a one-off or a two-off product, the pinouts do not always match up and some strange issues may occur. It's your choice, but you have now been warned.
Ray