- There are five IO, each IO can be Input or Output
- Among the five IO, two of the IO can perform as PWM
- Among the five IO, three of the IO can perform as Analog Input
If you are using Arduino (or any other TTL device) to control 4 channel relays or more, I would suggest to use ULN2803 Line Driver instead of Transistors or FETs. You can use ULN2003 which is much more cheaper if you plan to use not more than 7 channel relays.
The ULN2803 Integrated Circuit (IC) is a "Eight-way Line Driver". It allows you to interface TTL signals (5v) with higher voltage/current (50V/500ma) loads.
As shown in figure 1 and figure 2, an Arduino is control 8 relays, one using ULN2803 line driver and the other one using transistors, both circuit are equivalent.
The Arduino Duemilanove (not Arduino Uno) is control by a computer over the network or internet via PHP. This article assumed that you already install WAMP web server & Arduino driver in your computer.
My Arduino Duemilanove is connecting to the USB port of my computer, the USB serial com port is detected as COM4.
Original project is on http://www.circuitcellar.com/avr2006/winners/AT3296.htm published in AVR contest 06 by Steven Savage. But the link is not available any more.
The interface plugs into a PS2 keyboard port on the PC and accepts commands from the infrared remote. I'm using an ordinary DVD remote (38KHz) to control my computer.
The original schematic is not correct, I had make the correction for PC Data & PC Clock of SV1.