[posted] Lilla

Sandro

Well-known member
Dear friends, I'm proud to share my midi expander project (I would apologize in advance for the naivety of my code)
https://github.com/SandroGrassia/Lilla-midi-expander

I would say thank you to Paul and to all many friends who gave me support, tips, and energy in the last 2 years (since this project started).
In a month I should be able to do a video with some musicians friends... In the meanwhile hope to find the time to do a video-demo.
 
lilla_wood.jpg
Lilla is an open source project for a polyphonic midi expander, based on Teensy 3.6 microcontroller. Lilla includes:

devices/ICs:
n.1 Teensy 3.6 microcontroller
n.1 Teensy Audio Adaptor
n.1 flash memory chip W25Q128FV (actually testing W25Q256FV )
n.3 CD74HC4067 (16-Channel Analog Multiplexer)
n.1 128x160 TFT color display
n.1 HCPL260L (single-channel optocoupler)
n.1 CD4093B (quad 2-Input NAND Schmitt Triggers)

commands:
n.12 rotary encoders with pushbutton
n.8 pushbuttons
Teensy program pushbutton

interfaces:
midi in (DIN)
midi thru (DIN)
stereo line output
micro-SD socket

polyphony:
reading files from external flash memory: 6
reading files from internal memory: 12


Audio files and presets
Lilla uses 44.1kHz 16bit mono .RAW audio files, imported from a micro SD card. Lilla can store up to 100 "Sounds", up to 30 setup (Sessions), in a Session up to 8 Instruments which also can be layered.


Effects
Lilla includes 3 simple effects:
resolution: decreases the number of bits (16bit -> 1bit)
downsampling: decreases the sampling frequency (44.1KHz -> 344Hz)
saturation: limits samples value within a range

Settings
Lilla requires/allows the following settings:
MIDI channel
first octave number
Instruments volume control: each Instrument can be associated to a MIDI Controller
enabling/disabling effects for each Instrument
MIDI Velocity response: 4 curves / 8 adjustment points

Editing
Sounds, Instruments and Sessions have to be created by the user. All settings can be edited using a tree menus; Sounds of a Session can be modified on the fly (during a performance) with fast and direct access (pushbuttons).
 
Also tested W25Q256FV but I had an issue, looking like a loss of connection... as soon as possible I'd like to share .
Thanks
 
New look, new functions

Actually Lilla includes some synth objects (delays, VCFs, LFOs); this is how looks like:
D3.jpg
D9.jpg

These synoptics show how delays, VCFs and LFOs are placed along the sound chain:
D16.jpg
D15.jpg

Now waiting for new pcbs, with some minor simplifications:
- mini-jack instead of DIN plug for midi-in
- no unused holes
- no more screws for display

Yhank you for your attention!
 
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