RC-Time

Keith Hilton

From Chapter 5 "What's A Microcontroller"; I have wondered since 2004 how the basic stamp and RC-Time could be applied to an audio signal. With the exception of turning it on, off, or volume up and down. What would RC-Time added to the output of a guitar's pre-amp do? Crazy but interesting thought, as the sine wave voltage would be constantly changing. The RC-Time capacitor and resistor would be fixed. Might be distortion, but some guitar players use a lot of distortion.

Keith Hilton

Instead of the output of a guitar's pre-amp, how about adding RC-Time to the feedback loop of a OP-Amp used as a guitar's pre-amp? Has anyone tried this?

Mike Green

The Stamps, particularly the BS2, are relatively slow. An RCTIME statement takes on the order of 220us to execute and a lot of other statements are similar. A tight loop with an RCTIME statement might take on the order of 1ms to execute. That's in the low frequency audio range. You might be able to use an RCTIME statement to set the volume level using a voltage controlled op-amp and vary the volume maybe to make a tremolo or something like that, but the Stamps are not fast enough to do much more than that sort of thing.

The Propeller has been used to make a guitar effects box (see here).

Keith Hilton

Thanks Mike. Always trying to figure out how to apply the samples in the book.

erco

Per Mike, a Stamp is way too slow. A simple analog circuit will give better real-time audio distortion. I was just marvelling at my kids' $5 Toys R Us voice-changing megaphone, which has several slide switches to affect their voice from robotic to alien & more.