yes, atmega 328p is the same of Arduino Uno. One of them should be enough for all the machine. I'm developing a project that has much more calculations involved and the Arduino is working well.
Can I ask you which limitations did you find withe the Arduino IDE? I know that the Atmel IDE is more powerful but actually I had never found any limitation with the Arduino IDE.
thanks.
memory wise i could definitely fit it on the one chip if there wasn't as much temp monitoring throughout the system but even with that said a microcontroller is a single core chip so trying to run two continuous processes simultaneously won't work.
a form of temp control could be integrated to act as an interrupt but the accuracy of the control isn't ideal when dealing with that kinda temp or for trying to maintain a long lasting blade.
running temperature control on a single chip allows full continuous monitoring and control of the temp circuit without effect the rest of the system
if you don't think this is right drop me a private message and we can talk about it.
for the arduino ide it just isn't very efficient with memory and automatically including .h files because it assumes you need them isn't always ideal.
would like to hear about this project your working on. drop me a private message if you wanna chat about it