Home Automation over IP

It has been a while since I started with my home automation over IP project. There has been a lot of progress but also some changes in the original design.

Previous posts:

Home automation over ethernet
The home automation over IP controller

Software

Right now the micro controller board with the Atmega168 can read analog inputs, switch relays and dim LEDs using pulse width modulation. However no logical decisions are made by the micro controller.

To do the logics I made a client and server application with Java that’s able to run JavaScript files in a script engine. The Java application retrieves the values from the micro controllers, executes the JavaScript and sends the updated values back to the micro controllers. It acts like some kind of soft PLC, running on a simple language like JavaScript.

Because the JavaScript based soft PLC has no GUI I integrated an extra webserver in it. Now it’s possible to create fancy interfaces with Adobe Flash or any other development tool that’s able to get and send data over HTTP.

A complete cycle is as follows:

1. retrieve IO status from micro controllers
2. execute script
3. retrieve modified IO status from script engine and put it in the IO buffer
4. apply modifications received by the server in IO buffer
5. flush the buffer to the micro controllers
6. goto step 1…

To avoid to much load on the network a cycle is only ran once every 200ms. For industrial purposes this could be to slow but for switching on and of lights in your house this is fast enough. When pushing a button in a Flash movie the delay is barely noticed.

Hardware

Beside the point that the modules will not be build in to a housing that can be mounted on a DIN rail there are no changes on the hardware part.

Can I get the source and schematics from this project?

At the moment, no. It might get open source one day, it might be not.