I am new to Arduino, although not programming, and would appreciate some advice.
I have a Mega2560 and display for my HMI and want to add several 'functional nodes' for want of a better description. I need to make a sensible decision about which board to use for the nodes.
Nodes will have different functions but for example I will want one with several PWM outputs, to regulate charge current for different solar panels. It would be handy if it also measured battery voltage and temperature That would be 4 digital outputs and 2 analogue inputs.
Another one will need to handle my generator, temp fuel, speed ..... The actual functionality isn't all that important in the greater scheme of things, if space or scan time are tight I will simply split the functionality over a few units.
However communication's are less simple. I need a multi-drop, multi-master serial network. Devices will need to broadcast information, for any other device to listen to and then utilise, as well as being able to respond to specifically addressed commands. Obviously the serial protocol will need to handle multiple devices competing for a single bus, RS485 esque, and I would rather not have to muck about with handshaking lines if possible.
The network will need to have a star/spur structure and legs as long as 100m I don't know much about protocol specifics, other than RS232 which will not work anyway, and even less about implementing them within the Arduino IDE.
I would be very interested in your thoughts RE specific devices and how I might go about creating the required network,