Tone Control

[ksquared]

Is it possible to use, a variable tone generator to control your robot? 

Also.... is there a way to modify this circuit to be variable?
http://my.integritynet.com.au/purdic/square-wave-generator.htm

The creator is so aesthetically pleased with this design he does not like the idea as much, at least not in his Q&A.  I've built several 555 versions of these, variable and not, and would like to at least (kind of) build one to emulate those sans timer. 

Thanks!

[waltr]

Read the text: R1C1 and R1C2 determine the timing of the circuit. By making these variable the frequency can be changed.

It is possible to control a robot with a variable tone generator, also by whistling.
It just may not be great control.

[ksquared]

Is it possible to use, a variable tone generator to control your robot?  

Also.... is there a way to modify this circuit to be variable?
http://my.integritynet.com.au/purdic/square-wave-generator.htm

The creator is so aesthetically pleased with this design he does not like the idea as much, at least not in his Q&A.  I've built several 555 versions of these, variable and not, and would like to at least (kind of) build one to emulate those sans timer.  

Thanks!

Ahhhh.... yes you put that well...

EDIT:

"The ON / OFF period (called "mark/space" ratio for the purists) - look back at fig 1 that's what it's for, is determined by R1C1 and R2C2. If we make R1 = R2 and C1 = C2 it can be shown mathematically, (and I won't bore you) that Fo = 0.7 / (R * C)"

What is the equation from which that is derived?  If its not inconvenient, does someone more competent happen to see that?  Thanks again...