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).
