Hi, I am new to the arduino platform. I have been using a Lego Mindstorms NXT with the software that comes with it and have some experience in batch programming. My dad co-ownes a manufacturing company and wants me to design a system for him that can take the data from a switch (SPST and closes when cycles) that counts how many times the machine cycles and put it into a Microsoft Excel spreadsheet with each machine having its own count display. We have a price limit of about $5000-$8000 and want a system that can be expanded upon to around 30 machines easily. The arduino was my natural choice since I have heard of it being used in many projects.
The first thing I want to do is decide what interface to use. I do NOT want to have a few arduino megas that are monitoring multiple machines. It would take out the part of adding to the size easily. I have thought of using XBee modules on some fios, ethernet connection to a large hub dedicated to the arduinos, and coaxial connections. Connecting the Rx and Tx pins together is not an option as the area this will have to cover is a rectangle of about 1000yd by 300yd. Standard RF circuits are also out of the question as they would be interfered by the large 200hp motors and the large collection of other noisy goods. (both physically and RF)
My plans are to first decide a parts list, make a hello world demonstrating that this is possible, and finally buy the rest of the parts to make it possible. You will know when I buy them as stocks of one arduino or another will drop dramatically.
Just remember when you respond, I do not know much about the programming language and am still learning it. I plan to buy two arduinos tomorrow, a couple ethernet shields, and an xbee set. And just out of curiosity, what is the record of the most arduinos connected into a network like the one I'm planing on?