Building a operation system at store

The goal for a operation system is

1. to automatic inform store people the new order for delivery or return.
2. since everyone is alert, they are moved to pack the new order without any command.
3. my learning on electronic control of lighting and alarm fixture.

I have been working on it for about 2 weeks. Since the end of last year 2009, i have bought a 19 inches LCD to be install at the store. Another 14 inches old LCD will be installed outside the office. I have do the software in about 3 days and keep improving on it till now.

The control of the electrical lighting is the difficult part for me. I have learn to solder and bought a set of electronic parts such as transistor, resistor, breadboard and prefboard. I have also taught myself how to read a multimeter by asking my brother in law and read from the internet.

The first method to control using the keyboard numlock does not work for me. The voltage difference between the led legs are 2 volts. I could not build a transistor switch because of the voltage not to the ground of 2 volts. After reading some books from the GE library, i still could not get a solution. Then on a bus journey to my Sunday accounting class today, i thought that I am at my end, maybe I should change my problem definition.

I search internet on my iphone and read about using serial port from usb and someone has already done it with solid state relay with a usb serial port adapter. I think it will be my new path and working with software to control the serial port will be easier for me. Will be working on it next week!