List of hardware and software components:
a. Dorgem freeware
b. Inpout.dll c++ library
c. PHP and Javascript
d. Webcam
e. Server with .Net framework and unused printer port slot

Now, setting up the webcam surveillance should be easy. In fact, high performance webcam with built in FTP client and Wifi support is already in the market to be used in this kind of environment. If you are using Dorgem, it allows you to save the webcam image as file or via FTP easily in a predefined interval. The only tricky part is perhaps writing a Javascript or META to refresh the image in the user’s browser automatically in an interval.

Next is how we can control the external hardware via printer port. This can be done using the readily available libraries for the printer port here: http://logix4u.net/Legacy_Ports/Parallel_Port/Inpout32.dll_for_Windows_98/2000/NT/XP.html. I assume that you are familiar with the architecture and pin connections of the parallel port.

A typical printer port supports only up to 8 data bits. Although this is sufficient for control up to 8 devices, you can still extend the port by connecting the widely used PPI 8255.

After you have tested, compiled and built the printer port C++ or VB program, you need to write a simple PHP program. This program should utilize the ‘EXEC’ command to run the C++ or VB program. Your C++ or VB program should allow parameter passing with the PHP script.

Also to note is the low voltage supplied out from the data bit pins. This means that you may find it hard to use without any amplifying work. In my case, I decided to use a NPN transistor to amplify the signal so that I can use it to do switching through a control relay.

For more information about this project,  please contact me at sehhorng@gmail.com