My new house is outfited with an old (I mean 20 years old) intercom system. Although the system itself is still functional, I want to create a new open-source and flexible system to replace the existing system. Since my background is in Computer Egineering (which includes some electrical engineering), I thought it might be a good change of pace for me to move away from a software oly project towards something that is more electronic in nature. In other words, somewhat of a "crafts for geeks" project :)

I have already started to post about the project on SebbyLive but thought it might be a good idea to do a quick recap of what I have so far. Obviously not too much since I am in the early design stages.

Main Goal

The main design goal is to create a replacement for my current home intercom system. Of course, by taking advantage of current technology, I want to integrate features such as:

  • Touch screen LCD display, allowing a more friendly user interface
  • Support for streaming audio and video (from security camera or TV feed)
  • Home automation (control of lighting and other electronics) from the touch panels
  • Sensor integration such as motion sensors and temperature sensors
  • And probably much more as I start doing the actual design

With this in mind, I want to keep the design as open as possible so new features can be added in the future without the need for a complete redesign. The first step so far has been to select the right CPU and architecture to work with. Since one of my goals is to have a touchscreen panel in almost every room of the house there are a few key things I had to keep in mind.

  • Cost: Since there will be a panel unit in almost every room, the cost per unit needs to be as low as possible
  • Flexibility: Although there may be an initial set of features that will be integrated, the design should allow the addition of new features and sensors with little effort
  • Ease of Use: The user interface is an important part. Although, I am the geeky type. Non-geeks, such as my wife, need to be able to use the system
  • Easy of Installation: The idea is to make the installation process as easy as possible. Since we already have an old system in place, we want to use as much of the existing infrastructure as possible (as long as it does not interfere with other design goals)

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:
    • 32MB SDRAM
    • 8MB "burst flash"
  • 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:
    • One RS232 port
    • One CMOS-level port
  • 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)

TahoeTop

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 this month so I should be recieving my board within the next few weeks and can start playing around with it...