Mind you I started an internship so I haven't devoted the time necessary to tinker, but I can't figure out what the left toggle switch is mapped to and none of the sample code seems to use it.
Well apparently it's not mapped to any port which makes sense now that I've had time to read more. I'm guessing my switch is bad (or backwards?) since none of the effects (metronome, delay, etc) actually mix.
The "mix switch" is analog switch, this is why is not mapped to any port of the microcontroller:
If it is OFF (up position): nothing happens.
If it is ON (down position): the output processed wet signal from the Arduino board is mixed with the original input guitar signal. It is necessary to use it for some effects like delay, echo, chorus, etc...
Yetzederixx wrote: So switching out the mixing switch for a new one, and reversing it to match the toggle switches orientation, made no change in functionality.
Anyone got any troubleshooting ideas?
I should of said that changing out the toggle for a new one and changing its orientation didn't make it work. I get zero change no matter what position the switch is in.
Toggle switches don't have polarity, so they work the same in both orientations.
- With a multimeter you can check the connectivity:
- In one position it connects the middle point with ground.
- In the other position it connects the middle point with "nothing".
Hello,
I have 2 pedal shield boards : the PS rev G works fine but the PS rev F has exactly the same problem than yetzederixx one. The SW2 is a toggle switch ! Impossible to mix, it seems to have no signal on DAC0 or DAC1.
I spent few hours with schematics ... can't find the problem with my multimeter and now i will check with the scope.
Call you back for the results.
Hi, the change in revisions only affects the drawing on the back of the PCB, F and G (which is the current right now) have exactly the same layout and gerber files.
SW2 (on the left) is the mix switch,
- when is in up position, it allows the guitar input signal to go to ground, and never reaches the last summing op-amp.
- when is in down position, nothing stops the guitar input signal to go to the last op-amp in summing configuration.
To be sure that DAC0 and DAC1 are working properly you can load the sinewave generator.
Please be extra carefully checking DAC outputs,
it is very easy to blow them.
There are two test points on the shield to measure DAC0 and DAC1 after a capacitor, so there is no risk of high DC currents. Measure the DACs on pins 2 and 3 of the second TL072 is also a good point.
Thanks for your response, It's too late today for the scope but... by trying the shield without IC TL072, something strange happened :
With 2 TL072, power supply is -4.2V, +4.75V with USB connection.
With 1 TL072, power supply is -4.5V, +4.74V with USB connection.
Without TL072, power supply is -4.74V, +4.74V with USB connection.
With the metronome program, on the pin3 of the input TL072, i have 1V and in the forum it's said 0.1V...strange too...
Ok for me for the SW2, in_buffered signal to the ground (up) or added to DAC0 and DAC1 (down) in entrance of the output AOP.
I wish you a good night for today and call you back latter with my progress...
I remove those two TL072 : no problem of pin... and put it back in the board and, fantastic, now it works...
I believe there were a contact problem with one TL072.
As my scope was ready i took few pictures of signals.
The distorsion is interresting to see with a very small square signal when the sound is good. The loss of level is impressive before a good distorsion.