I am in the brainstorming phase here. Any help is appreciated.
Here in the 35,000 ft2 school we have 12 2-stage HVAC rooftop units (RTUs), each with a thermostat attached. The current thermostats are controlled with 24VAC, supplied by the RTUs, with battery backup. I would like to accomplish the following:
- Consolidate all of the thermostat controls to one central location with a display and buttons for control.
- Take temperature readings in a maximum of 35 locations in the building and deliver them back to the central location (master arduino?) for logging/analysis/and thermostat operation.
In its most simple form, that is the idea. The end goal will include a bank of 7 segment or lcd displays and a set of buttons for the different units to allow control similar to a traditional wall-mounted thermostat. Perhaps one day a web interface with graphs, etc.
I am pretty sure I will need an arduino for each RTU, although, perhaps I can get enough close together to consolidate two or three units to be controlled by the same board. In other words, I don't think I can run 200 feet of cable from the contacts in the furthest RTU directly to an arduino in the central location. (I think there are some distance limitations for the cable here.) Hence a separate arduino for each unit, I am thinking a pro mini, perhaps?
Physically connecting things will not be a problem, nor will running any additional low voltage for arduinos or sensors, we have a drop ceiling and plenty of space to play with.
Now for my questions:
- For sensors, should I go the route of 1-wire devices, and if so, can I control them with an adapter like the HA7S or the DS2482-800? Or should I look into something else?
- Am I beyond the capabilities of an arduino network, should I jump to something more robust like a Raspberry Pi? Or maybe combine the two?