[bjpirt]

One of the nicest data through sound implementations I came across was in a kid's toy (often the best source of innovation)

It was a "Bob the Builder" play set and when you wheeled around a digger, etc the main base would play a matching sound. I immediately started investigating and was impressed to see no batteries in the movable vehicles. I realised that each vehicle made a clicking sound as you moved it and the ID was encoded into this which the base station picked up. Pretty impressive to do this regardless of how fast the vehicle was moved by the child.

[stavros]

Was it based on the frequency of the click?

[sejje]

>Pretty impressive to do this regardless of how fast the vehicle was moved by the child.

Probably not, eh?

[stavros]

Probably yes, because the frequency of a note doesn't change based on how quickly the next note is played after it.

[sejje]

Guess I misunderstood. The first time you said "frequency of the click" -- I would personally respond with clicks per second.

"Frequency of the note" in your next comment clears it up. It probably was that, you're right.