I would like to use a RGB OLED, 1.5inch diagonal, 128x128 pixels, 16-bit colour oled display with embedded controller, communicating via SPI interface. You'll need to design a simple processor board to interface to the display and code it to have a graphical display to look like a standard analogue audio VU meter. The design must be able to display 2 x 3 different audio inputs (1: input level, 2: Output level, 3: Gain reduction....This would need to be x2 for Left and Right channels. (so a total of 6 possible audio sources) and be able to switch between them and display the level correctly and show which input it is displaying. The user needs to be able to select a single channel (L or R), then the source (1, 2 or 3), and a meter type (Bar or analogue) then display that "full screen", OR select both channels and display any combination of meter and input, but both displayed at the same time. EG: L channel, VU meter, analogue meter, input 1 (on left or at top of display, wherever it fits best), AND R channel, Gain reduction, Bar graph display, input 3 (on right of display or bottom...as appropriate). The meters must have the same ballistic characteristics of a standard analogue audio VU meter. Accuracy is a MUST. Colours should be used intelligently and should have a good resolution. The display may be used in either a Mono channel unit or a stereo channel unit, so there would need to be a hardware link on the board to tell the processor to always use the full display in a mono unit (so second channel selection Etc is disabled), or split the display intelligently for a stereo unit (showing which channel is which) and enable the second set of 3 inputs (and be able to switch modes independently on Left and Right channels). Expected display to be used is something similar to this: https://www.amazon.co.uk/Waveshare-1-5inch-RGB-OLED-Module/dp/B07DB5YFGW/ref=sr_1_1?dchild=1&keywords=Waveshare+1.5inch+RGB+OLED+Display+Module+128x128+Pixels+16-bit+High+Color+SPI+Interface&qid=1626291291&s=computers&sr=1-1
The versatility of the display will likely be added to in the future (maybe to add the ability to display Eq response curves/spectrum analyser.
Development hardware will be supplied at my cost.
You can supply schematics for the prototype processor board and I would layout the PCB and have them fabricated and then sent to you for prototyping/code testing Etc.
I would prefer to use either a PIC processor or a Silicon Labs MCU