Got it - didn't realize that in a mono jack S&R are shorted, but of course they are.
But, there's always a way.
A digital switch/relay SPST NC could be put at this junction for a foot switch:
Then in software for a foot switch, the switch...
Mono jack will not work with this socket configuration. A mono jack has the Sleeve+Ring as one contact. The jack socket in the circuit above has the T+R shorted = all three contacts will be shorted to GND, no matter what the switch position is...
@Pio. Ok, first of all, absolutely brilliant! You are so far ahead of my understanding and I start to get what you're doing here. Just fabulous!
I wonder if a digital pot could be used for RV1? Something like this...
Fantastic ideas!
In fact I was headed that way thinking about using a relay or an analog switch IC, which sounds similar to what you suggested.
Probably an analog switch would be the way to go because it’s solid state and then I could implement...
Back in the days of old (yes, I am that old), we used to use CD4066 digital switches to be able to route signals from anywhere to anywhere under microprocessor (8051 and/or 8085) control. I don't know what a modern-day equivalent of the CD4066...
Hi again @Pio, just a question on the inputs - it looks like T and R are both connected?
Am I understanding the schematic correctly? I guess I'm not clear on how this could work then? Is this circuit meant to somehow handle if T/R is flipped to...
Absolutely incredible @Pio - seriously you've been so incredibly generous with your wisdom and your time! Honestly, your response is an absolute wealth of information!!!
I will go through it slowly to understand it as well as I possibly can. I...
with the input connection as in the posted schematic, where R+T are tied together, there is no need to swap the polarity. The pot acts as a single variable resistor in both configurations.
I would advice against it. It looks like the MCU used in...
Hi @Pio, I really appreciate your time in explaining all of that, plus the demo link. Very cool.
I want to be able to reverse the pin definitions in software, and not rely on an external switch if possible. I don't see the circuit above being...
Made this simulation:
https://www.desmos.com/calculator/ycpupbbkec
It shows another drawback of this solution: R1 + pot inside the Expression pedal create a voltage divider with the variable bottom resistor. This changes the taper of the pot...
Yes you are right, for the polarity issue where Sleeve and Tip are reversed in the pedal.
However, many pedals have the Tip and Ring reversed - which is wiper and positive.
In past that made it so you could only make a hardware device work with...
Also, sorry, one more question - I was planning to change the definitions of ADC and 3V3 pins in software to accommodate the main expression pedal wiper implementations. But I don't see how this can work with the schematic above. The shottky's...
Hi @Pio, I really appreciate the time you took to share the schematic.
Would it be asking you too much to take me through the purpose/function of the components? I'm pretty clear on the capacitors - C1 is just to filter jitter from the ADC, and...
Simplest way, which is safe and handles both plug polarities would be to use the pot as a rheostat:
Downside is it requires calibration for the max range and depending on the pot resistance the range will be different.
Well I'm looking at that schematic I posted and I can see the two 47R resistors are not doing anything useful - if T & R are shorted, they will not current limit anything. I can be a little dyslexic/confused about this sort of thing. Of course as...
OK, here's my first attempt at a schematic for the concept. I would welcome your (even harsh) criticisms. This needs to be bulletproof.
Pins 14 and 15 were chosen because they can act as both digital and analog pins, allowing for T&R functions...
Just to add one more thing - I need to also protect in case someone plugs in a switch-only pedal instead of an expression pedal. Expression pedals use potentiometers; switch pedals are just switches on/off. The switch-only pedals use a 1/4" mono...
Hey all, was considering adding a pedal input to some MIDI faders that use a Teensy 4.1. I'd like the pedal input to accommodate lots of different pedals if possible. But as many of you may know, some pedals reverse wiper/positive, and this can't...
I think that's a good approach.
I have also asked a couple companies that make this screen to see if I can get a schematic from them for an external module, since they already make one, albeit too large - that would be the ideal situation. I'll...
Thank you @skpang. I saw that 12V and was confused because this screen can be powered from 3.3V. So I assume there must be some voltage tripling circuit. In the tentative schematic I only included what was in the data sheet, which obvs is missing...
Your schematic like that is not going to work. If you look at the OLED module there is U2 and L1. You haven't got there on your schematic.
On the OLED panel pin 2 is VCC. Look at datasheet section 4.3 page 10. VCC requires a voltage of 12v. You...
Looking at the picture it is almost possible to see the tracks.
I would suggest that you buy the display with the mounted control circuit and try to figure out the circuit from there,
It will also give you a completed part to compare with yours...
So I found another data sheet for (ostensibly) the exact screen - I imagine there's probably just one maker of this one and it looks the same. That's an assumption tho.
Here's a link to that datasheet...