There seems to be a lot of digital noise breaking through from the microcontroller to the analogue side. It might be PWM artefacts or just electrical noise pickup. It is particularly bad when using the display.
I've tried several power supplies and running from a 9V battery and the noise level is the same.
The board I'm using is the Keyestudio MEGA 2560 R3
Currently the noise level is such that the pedal is unusable.
sorry for my late reply, during the Christmas Holidays we have been away
It might be PWM artefacts or just electrical noise pickup. It is particularly bad when using the display.
to make sure if it is the input or the output stage the one that is creating the noise, you can try to load a sinewave generator and check how it sounds. Usually, the sinewave sounds great.
I've tried several power supplies and running from a 9V battery and the noise level is the same.
The power supply is 99% of the times the source or noise, so it is good to check that.
Currently the noise level is such that the pedal is unusable.
Arduino was never conceived for hi-fi audio, it is normal to have some background hiss but not no make it unusable.
The board I'm using is the Keyestudio MEGA 2560 R3
We had bad past experiences with Asian Arduino copies, sometimes they have a "cheaper" power supply that injects too much noise everywhere. It would be ideal if you could borrow an official one and see if the problem disappears..
It's been a while but I finally got a genuine Arduino Mega to test with.
I checked the voltages on your diagram and all was good except the two positions marked 3.7V (20 and 21 on Arduino header) that have serial data/clock so not possible to check with a simple multimeter.
Digital noise is still dominant when signal is through the effect. It isn't mains hum or audio hiss and it's very loud.
Do the effects sound as how they are suppose to, or sound kinda weird?
Tried Bitcrusher and if you have, does it actually sound as a effect or not?
As with mine, the bitcrusher doesn't actually work, if you go to setting 9 it just goes haywire. (similar issue as described by another member in the troubleshooting thread)
Plus whatever effect i have chosen to place on it, they all sound really terrible, not to mention the pedal is just noisy.
Plus whatever effect i have chosen to place on it, they all sound really terrible, not to mention the pedal is just noisy.
I am sorry to hear that, usually with the bit crusher you start feeling the effect after crushing 2 bits.
Maybe your input level is not high enough? try with the VR1 potentiometer, to get more input signal.
Arduino was never designed as an audio processor, with the pedalSHIELD project with "hack" the board so you can have fun and experiment programming your own effects. Usually, similar platforms use expensive components (and very hard to DIY as they are SMD, not through-hole), and of course, that systems use their own DSP language, which is way more complicated than plain C.
Because of that, the sound quality of the pedalSHIELD project is not the same as the one you would get from a pure analog guitar pedal. You will always get some subtle digital artifacts and low-level hiss, but the benefits from building your own guitar effects
Please tell us when it starts to noise.
It generates while you touch anything, Uninterrupted, or when you plug something in?
Why you call it noise?
Noises either way can generate inside of your circuitry or an external sourse.
What kind of noise is it?
Is it glitchy weird things that depends on presence of signal? (Try unplug guitar)
Or stable hummy kind of thing in background?
Not sure about that "Keyestudio MEGA 2560 R3" but try to borrow an original one from a friend to troubleshoot. Or at least look up if anybody else has a same issue.
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Noise have to be made when something is getting wrong however, people use to avoid it for some time but late on these noises use to irritate everyone and specially in IT related work
The bottom line is that the approach taken to pedalSHIELD MEGA is more " interesting idea" than a practical pedal.
Even just passing through the Arduino with no processing at all, the noise level and unpleasant distortion is unacceptable.
Using the Arduino PWM outputs for audio D/A is never likely to give usable results. Using a simple passive ladder network D/A would work better.
