Determining the Right Platform For the Panels

Although you may think the server architecture (i.e the box that drives everything is the most important), I believe the key factor in getting my system running is making the right decisions in terms of the architecture that will be used for the user interface panels. There are several key considerations that need to be factored in when making the desicion.

Consideration: Cost

Cost is probably one of the most significant considerations that needs to be made in regards to choices for the user interface panels. Since there will likely be a panel in each room, the overal cost of an installation will be directly proportional to the cost of each individual panel. Other components such as the server is a one-time fixed expense and altough also cost sensitive, it will definetly have less of an impact on the overall cost of a project.

Consideration: Flexibility

Flexibility is another key factor for me. Although there are a certain set of features I am interested in from the start, I want to be able to add additional features in the future. This means that the hardware (and software) should be flexible enough so that new features and hardware components could be added later on with minimal effort.

Consideration: Ease of Development

Well, call me lazy. But this project is indeed a part time hobby. So I want the best and quickest return on my time. So the architecture that I pick should be easy enough to develop for that the amount of time dealing with specific quirks be minimal. To me this also implies the need to use a high level language rather than writing and debugging assembly code.

Possible Options

I Spent several days surfing the net and looking at several options. Then I came across one processor/architecture option which answered most of my needs.

Freescale has unveiled a reference design that runs the .NET Micro Framework and targets Windows Vista SideShow, among other applications. The i.MXS Development Kit is based on a highly-integrated SoC (system-on-chip), and supports designs such as external laptop displays that run mini-applications without booting-up a laptop. The core of the kit is a small form-factor reference board based on a Freescale i.MXS applications processor, a "highly integrated" SoC built around an ARM920T processor. The kit also includes a 2.5-inch QVGA color LCD panel, a USB interface, and an expansion connector for add-on modules to support functions such as Bluetooth or ZigBee wireless.

Key features of the development board, according to Freescale, include:

• Processor -- i.MXS applications processor, based on ARM920T core
• On-board memory:
• I2C and SSI bus connector for connection to external audio CODEC SMbus interface
• On-board 2.5-inch QVGA resolution LCD with backlight
• USB 1.1 interface
• Serial ports:
• 11 digital I/O lines for keypad/button inputs
• Clock source crystal: 32 kilohertz
• LED power indicator
• Powered by USB bus voltage or external power adapter
• Provides headers for custom add-on modules 

That being said, the actual dev kit from freescale is fairly pricey at $600. But two main things stood out. The all in one processor offered by free scale. And the new .NET Micro Framework. Ok, I am biased since I do indeed work for Microsoft. But the idea of being able to develop the home automation code in C# is really attractive to me and would make the process so much easier. After digging a little more I stumbled upon a company named Embeded Fusion which has been developing it's own .NET Micro Framework solution around the freescale architecture...

The "Tahoe" development platform provides an ideal development system for the Meridian CPU and the .NET Micro Framework. The platform includes:

• Meridian CPU with .NET Micro Framework
• 2.7 inch LCD
• Push Buttons (9) (5 arranged in classic NSEW with center pattern)
• Easy access to all of the pins from the Meridian CPU
• Power adapter
• DB-9 serial
• SDK with customized emulator for .NET Micro Framework
• Lot's of sample code! (Including custom emulator extensions and managed drivers)

Their dev kit does appear to offer more options and is more attractively priced at $300. So I have ordered one. :)

They are starting production in April 2007 so I should be recieving my board within the next few weeks and can start playing around with it...

The .NET Micro Framework

The use of the .NET Micro Framework  is a significant plus for me. Like I sasid, I am biased since I do indeed work for Microsoft. But the idea of being able to develop the home automation code in C# is really attractive to me and would make the process so much easier. And this also allows me to have a potentially heterogenous configuration of panel architectures in the future as long as they have support for the framework.

As an example, below is a video that shows the framework in use for the development of a simple Space Invaders game as well as a control mechanism for a robot. It's pretty sleek and neat!