All that's needed is a Webcam, Flashlight, Free Software, and about $15 worth of analog electronics that you can get from radio shack.
This system allows remote control (via the internet) of actuators (motors, etc) at your home. It works by sensing changes in brightness at particular locations on your home computer screen (locations at which the sensors are taped). These changes in brightness are remotely controlled by you via a yahoo messenger webcam video feed between your work computer and your home computer.
For example: you're at work with a computer, a webcam, and yahoo messenger's video broadcasting activated. Your home computer is also running yahoo messenger and has a full screen view of your work computer's webcam video feed. At work you shine a flashlight into your webcam's field of view at specific locations. By varying where you shine the flashlight into your work computer's webcam you will be activating different sensors/motors at your home computer.
If this is confusing make sure to watch the video.
Advantages of this system over much more complicated systems:
= Optical isolation of PC from actuators (motors, etc)
= Uses only cheap analog components available from radioshack
= Allows control of as many actuators as desired.
= Does not require knowledge of computer programming, or server administration (i.e. PHP and Apache)
= More secure than remote desktop access software such as VNC, etc because yahoo messenger does not allow access to control your entire computer. (as far as I know,.....this last advantage might not be totally true :)
Step 1: Supplies
soldering iron $8
wire wrapping tool $7
(you can wire wrap directly onto component leads instead of soldering. it's less permanent but ok for prototyping)
30 gauge wire wrap wire: $4
needed as a flexible wire between screen mounted photoresistors and the breadboard.
photoresistor 5 pack: $3
2n222 transistors or relays $3
DC power supply (you probably have this): $20
you can find these in the garbage, or you probably have spare ones from appliances you don't use any more. the voltage output you need depends on the size of the motors you use. many medium sized motors need between 9 and 12 volts.
breadboard for testing $8