RC clock speeds are pretty inaccurate, if you consult the datasheet it gives the formula - but it probably won't be very close to the calculated value. Basically you only use an RC clock when the frequency doesn't matter.
The diagram you posted uses an old OTP PIC, you should use a more modern FLASH/EEPROM device that you can reprogram - also a number of the more modern devices (16F628, 16F819 etc.) have internal oscillators, it's probably a good idea to use those.
I know the pic is an older otp, but thats what is used in the orignal circuit, I'm just looking for a quick hack of this circuit to get the lights to change patterns/flash in reponse to music. So my plan was to just connect the clock somehow to an audio signal, (via VU meter, VCO, ect).
I know the pic is an older otp, but thats what is used in the orignal circuit, I'm just looking for a quick hack of this circuit to get the lights to change patterns/flash in reponse to music. So my plan was to just connect the clock somehow to an audio signal, (via VU meter, VCO, ect).
I don't know how it would work?, with a PIC that you're programming you could set the PIC to use an external clock (or for some OTP ones, buy the correct version of chip) - but this PIC is already programmed to use an RC oscillator.
Without the external oscillator components you 'may' be able to simply feed an external oscillator in to the oscillator pin?, but I've never tried it, so don't know if it would work or not.