tx'ing/rx'ing general questions on methods.

Hello, i have more of a general "overview of methods" question. i will use an example for this. ipod controlling, "http://www.rosiedaniel.com/2007/09/ipod-arduino-love.html" for example, progomatically, how to they "sniff" the serial bus? how do they obtain the hex code for button pushes? how do they display it so you can see the data incoming so you can replicate it? sorry for all the questions, my main goal isnt to interface to an ipod, its more or less in the long run learn how to interface with existing controller boards etc. more for curiosity though.

does anyone have a link to a source code example?

or a link to a schematic of external serial wiring etc?

Don't have an Ipod, but in your example, the Serial bus isn't really sniffed. The arduino is just connected and apparently the Ipod expects serial commands. The arduino also checks which pins(/buttons) are activated and if one is it sends the responding command to the Ipod.

In this specific case, arduino is more or less sniffing an number of input pins for changes, sends 'm to the Ipod and... the Ipod more or less sniffs the data stream for commands.

Loads of devices controlled by a serial port require special commands to function. If you wanted to control an Ipod you would need to get a list of commands possible, find out how to get the Ipod in command mode (if it isn't in that mode standard already) and send the right commands.

In some cases the commands needed may seem quite cryptic, in other cases they're more text-based.