Haven't posted for a while as I've been too busy drilling holes in walls, laying cables and generally trying to automate everything in sight. Heaven knows what will happen if the dog sits still for too long :-) But back to the plot. One the last update I'd got the basic hardware for automating the hallway lights installed and was about to install Cortex (the controlling software for Idratek).
I have to admit I'd thought long and hard about the platform to run Cortex on. Cortex runs under Windows so it needs to be a PC of some sort, but it's going to have to be on 24x7 so ideally it needs to be quiet, reliable, with a low power consumption and not too hot. It must, repeat MUST
, have a native RS232 port on it to allow it to talk to the Idranet system. It would also be useful it was small and could be mounted on a wall. As the system was going to be running 24x7 I also decided I wanted to run my music server (Slim Server
) on it and to have it act as a central file server, hence it'd need gigabit Ethernet and I'd need to be able to fit a fairly large hard disk to the system.
All of these lead me to look at the mini-ITX form factor (http://www.via.com.tw/en/initiatives/spearhead/mini-itx/
). For those of you not familiar with these, they are small form factor x86 motherboards with low-power consumption CPUs which means they can run unmodified Windows. They're aimed at the embedded market for building into other things where you need a PC as the controller. They're a little bit more expensive than standard motherboards but come with the CPU already fitted so all you really need to do is all memory and a disk.
The board I decided to use was the Via EPIA EN 12000G Fanless C7 Mini-ITX Board (http://www.via.com.tw/en/products/mainboards/motherboards.jsp?motherboard_id=399
). The advantages being a relatively high CPU speed (1.2GHz), DDR2 memory, SATA and Gigabit ethernet. While there is a slightly faster 1.5GHz model, the 1.2GHz one is fanless. The power consumption for this board is 25W, add about 10W for the disk drive and the system uses somewhat less than a 40W light bulb - not bad for a PC :-).
While there is a fine tradition of building mini-ITX boards into some really obscure things (http://www.mini-itx.com/projects.asp
) I decided to use a commercial case and went for a Travla C137 Mini-ITX Case - Black 120W (http://www.travla.com/Products/products.html
It's small, neat, takes a 3.5" HDD and a CD-RW drive and comes with brackets to allow it to be bolted to a wall. Perfect! Well nearly ... the EN12000G motherboard is quite new and it turned out that when you fitted it and the CD-RW drive to the case it doesn't quite fit. However a certain amount of swearing, bodging, and fairly heart stopping flexing of the memory DIMM later, it all fitted. <phew>
The CD-RW, USB and a Compact Flash slot are mounted in the side of the case and you can see the wall mounting brackets below.
I deliberately went for one with a CF slot so as CF capacities get larger and cheaper I can think about moving to a "diskless" system with the O/S and Cortex running from the CF. Additional data such as music files would be held on the HDD.
Once the hardware build was finished the O/S (Windows Server 2003) went on relatively smoothly and Cortex was loaded. I also loaded my music server (Slim Server
), and enabled the web server in Windows. Apart from that I left it alone. Over the years I've learnt that Windows can actually be a very stable O/S. The secret is to limited the number of jobs it's doing and not to fiddle with it.
Next: My Brain Hurts ...