Latest prototype Organ with arduino display show and tell

[MichaelPNolan]

This build now has 1 Red 2 RGB digits and 4 digit alphanumeric.
The 3 decimal digits are shift registers that control the colour channels and send binary to a binary to 7seg decoder. Old school logic circuit. The Alpha is an i2c LED backpack.
Here is a short example where USB midi keyboard controls are mapped

https://youtu.be/CfiCZWL8iYY
You can get 7 colours Red, Green, Blue, Yellow, Purple, Teal, White

inline void Organ_SetDrawbarInv(uint8_t id, uint8_t value)
{
#ifdef USE_ML_SYNTH_PRO
    OrganPro_SetDrawbar(id, value);
#else
    Organ_SetDrawbar(id, value);
    setDigitsColor(id%8);
    setDigits(value);
    textAlphaDisplay("Bar"+String(id));
#endif
}

Yes, you could just do it all with i2c but the RGB 7 seg digits seems quite rare. I wanted that because my Arturia midi keyboard has that kind of 7 seg in it. So if they can make that do most of the paramater feed back I should be able to do as well.

I've also got Midi-in, Midi-out and Midi-Thru build for this board if you see the white headers that is for that. So it doesn't need it's USB host. I thought I'd just like to put more time and build this and if its good enough i'll make a PCB for it. I keep thinking of other things that I need or then ideas that get rejected.
I've got the 16 channel multiplexer analogue for 8 pots + other things. I thought to make some resistance ladder selectors or buttons to get the most out of under used analogue channels.

Why?
Well one of my other things is to refit old casio keyboards - so ultimately I want to have even more - GPIO expanders etc. To map controls from the old keyboards to the ESP32 project (or other microcontroller builds). So I'm trying to build a PCB that can be programmed up to use various hacked in controls and map those to whatever project.

I've been mapping out and expanding my projects - once i've gone as far as I can then I'll know it's time to focus on PCB design but I wire things up hoping that the process of making over and over teaches me more for the next prototype.

The backpack makes the alpha sit a bit higher when I stuck it onto a perfboard with the LED. I have to cut the chassis for this to mount
O```

OrganESP32 allocation	variable
		GPIO
		0
Serial	programming	1
ShiftReg	clockPin	2
Serial	programming	3
ShiftReg	latchPin	4
USBHost-VSPI	CS/SS	5
Unusused internal SPI flash		6
Unusused internal SPI flash		7
Unusused internal SPI flash		8
Unusused internal SPI flash		9
Unusused internal SPI flash		10
Unusused internal SPI flash		11
ADC_Multiplex	?	12
ADC_Multiplex	?	13
AND-ShiftRegEnable	enableShiftOut	14
ShiftReg	datapin	15
MidiSerial	input	16
MidiSerial	output	17
USBHost-VSPI	SCK	18
USBHost-VSPI	MISO	19
OLED	SDA	21
OLED	SCL	22
USBHost-VSPI	MOSI	23
I2S	BCLK	25
I2S	DataOut	26
I2S	WCLK	27
ADC_Multiplex	S1	32
ADC_Multiplex	S0	33
ADC_Multiplex	ADCSignal-in	34
		35
		36
		39

[marcel-licence]

Thanks a lot for sharing. Very nice to see! I didn't know that this kind of RGB display exists. I can imagine that you could also benefit from the dynamic MIDI mapping. That would allow remap the existing pots to different functions.

[MichaelPNolan]

Yes, in fact one of my projects has banks and switches the midi mapping to map different function calls. Your functional programming with functions as parameters was good for me to learn.

void rewriteMidiControllerMapping(uint8_t mapNum){
    switch(mapNum)
    {
      case 0:
         midiMapping.controlMapping = tunaWorlde;
         midiMapping.mapSize = sizeof(tunaWorlde) / sizeof(tunaWorlde[0]);
        break;
      case 1:
        midiMapping.controlMapping = tunaWorldeBank1;
        midiMapping.mapSize = sizeof(tunaWorldeBank1) / sizeof(tunaWorldeBank1[0]);
        break;
    }
}

Simply switching different midiControllerMapping records hardcoded in the z_config

As for the alphanumeric I'm thinking of writing the footage so people can see if its octave or other interval, or maybe the interval name.

 No.   Harmonic   Interval   Footage   Color 
 1   Sub-Fundamental   Sub-Octave   16'   Brown 
 2   Sub-Third           Sub-Third    5 1/3'   Brown 
 3   Fundamental           Unison      8'   White 
 4   2nd Harmonic   Octave      4'   White 
 5   3rd Harmonic   Twelfth      2 2/3'   Black 
 6   4th Harmonic           Fifteenth     2'   White 
 7   5th Harmonic       Seventeenth   1 3/5'   Black 
 8   6th Harmonic       Nineteenth      1 1/3'   Black 
 9   8th Harmonic    Twenty-Second  1'   White

Yes it took me a while to find
https://www.sparkfun.com/products/13999

You can find cheap asian variations of the 14 segment but those are mono-coloured but i simply have one thats got a green and red section, purely by what they sent me.

https://www.lazada.co.th/products/i1897048436-s5958320125.html?urlFlag=true&mp=1

[MichaelPNolan]

Its kind of boxed - powered, holding together ... because I incrementally added parts like the variable voltage button row that is using the ADC to read and a switch statement to trigger commands. I added the alphanumeric and finally i had to link the ADC multiplexer breakout board with 8 wires. I used these female dupont headers - its really quite flakey. I did it 2 times and eventually had to bend pins to make it slide on to the male headers on the circuit board firmly rather than just almost fall off. So there might be something half baked about the dupont kit

I made a video to just show where it is up to.
https://www.youtube.com/watch?v=kK7-ysm-fbs&t=189s

The way I have sockets for the ESP32 breakout and the DAC has been robust from the start. Having plug in connectors for the face of pots, buttons so I could remove it and work on it has made me think I need to get a much better crimping solution for ribbon cables like an "Hobbytronics. 40 PIN IDC Crimp Connector for Flat Ribbon Cable" as you would find on PC motherboard designs or.
Its amazing how fast you run out of pins. There was 20 for the LEDs and 5 for the Alphanumeric (I2C with 3.3 and 5v) and 8 for the 16 channel multiplexer. I ended up with 5v DC coming in and 3.3v reference to drive the potentiometers going out (using an op-amp). On the board is another 3.3v regulator for all the TTL logic chips.
If you don't have 9v power it will power up using the USB in to the ESP32 breakout since it only uses 0.1 to 0.2 amps but the "Vin" pin of an ESP32 puts out more like 4.5v than 5v. That's fine but then my pots have a slightly different voltage.
I didn't want to run the pots with the same 3.3v supply as used elsewhere - I always feel its more stable to isolate the pots power from the rest of the board. That way there is less chance of one part of the project causing the sagging voltage in another.

This is an open-ended design where I tried to leave capacity for future additions like another i2c socket is preset for the OLED and I could still fit a GPIO expander in there and add more things.