Connecting pc to real world

I'm in the early stages of planning a HA system for a house we're going to
build in about 2 years. I'm a DIY kinda guy and am planning to use a
touchscreen pc to control security, heating/cooling, solar water heating,
landscape watering etc. We're not real big on audio/video, so probably won't
have any of that integrated into the system. Writing the code to control
everything is within my abilities. My question is how does the pc
communicate with the real world. The touch screen that I'll be using has a
USB port and a serial port. How exactly do I connect the various sensors,
both contact closure and analog to the pc and how do I connect the pc to the
various pumps, valves and external systems to be controlled? I presume some
sort of I/O device that plugs into either the serial or USB port and
provides X number of 'channels', but I've googled around and haven't come up
with anything. I'm looking at perhaps 100 input and half that number of
output channels. How do you guys do it?
Reply to
Paul in Redland
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USB is rather limited as far as distance. After about 12' you need a repeater.
Your best bet is serial. I would recommend converting the serial to RS485. You can then find lots of devices that can daisy-chain on the RS485 bus. There are also ways to expand a single RS232 port to handle a lot of I/O. A few places to visit to get an idea of what's available...
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Have you considered using TCP/IP?
"Paul >I'm in the early stages of planning a HA system for a house we're going to
Reply to
Dave Houston
One way is to use cat.5 ethernet cable or telephone cable then connect many mcu's in a one-wire communication in a open-collector setup. Use spare pair for power.
Reply to
Probably the easiest way to connect your computer/house to the world is through web based applications. You could use the Apache web server, or ready made products like HomeSeer for the server side. I/O on the computer seems now to be mostly via a serial port (or USB to serial adapter, search ebay for edgeport and similar adapters). Below is an inexpensive serial I/O board you could get to start experimenting with.
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