Curious if anyone has managed to tame voltage output well enough for getting quantized pitch values out of bela pepper.

Assuming 5v output, mapped 0-1 within PD, 1v would be equal to .2 in PD. Divide that by 12 for semitones and you get .0166666666 (6 repeating).

The problem appears to be that real voltage output deviates quite a bit from calculated values within PD. The deviation also seems to grow slightly as pitch gets higher. I know this is expected because analog values are not THAT precise.

Has anyone ever found a way to compensate for this and get closer to desired values?

hmm the DAC output should be very precise, on rev A and rev B capes. The newer rev C, which we started shipping this January, may have a channel-specific scale and offset error and you should use calibration to fix that. E.g.: measure the voltage at 0.2 and at 0.6 and use those two values to rescale your range so that it tracks well between 0.0 and 0.95.

    giuliomoro thank you. I had been playing with scaled output, but not correctly. I have pepper tracking beautifully now.

    The question I have is, if I share this with other people, will that scaling goof up their tuning?

    I did receive a Rev C board only a few weeks ago shortly after you got them in stock.

        jonbenderr The question I have is, if I share this with other people, will that scaling goof up their tuning?

        yes. The scaling calibration is board-specific.

            giuliomoro that's kind of a bummer, but understandable.

            I guess anyone who took the leap into this world is probably well equipped to deal with those adjustments, so I will still be sure to share once my current project is wrapped up.

                jonbenderr that's kind of a bummer, but understandable.

                I mean, the difference across boards should be minimal, but if you are looking for mV-accurate CV out, then individual calibrations are needed.

                What does your calibration code look like right now?

                    giuliomoro sorry for the delay.

                    So I ended up just using a scale~ object right before the output.

                    So the attributes for that were hi/low input of .2 to .6 to hi/low output of .185 to .5728. I know those values seem very random, but I was just subtracting the difference of actual output from desired output...which lead to near perfect voltage output of 2 volts, 3 volts and any other voltage desired.

                    Also might be worth mentioning I am using the properly built cyclone externals.

                    I'm kind of thinking maybe I could build some sort of calibration routine into the patch? Not that I think this is going to be of some great interest to anyone, that might be a fun project though.

                    It's actually a recreation/interpretation of the Eventide Misha/Samchilean/interval style sequencer.

                        jonbenderr I'm kind of thinking maybe I could build some sort of calibration routine into the patch? Not that I think this is going to be of some great interest to anyone, that might be a fun project though.

                        i think that would be very helpful ... I think you'll need to measure at least one channel's output manually with a DVM in order to use it as a reference to calibrate everything else.

                          5 days later