Midi music eight step sequencer demo for Adafruit Trellis keypad. Driven by Arduino Uno. Button data sent to Midi Shield. Midi data sent to Yamaha Midi sound module.
Top six rows used for entering note data. Up to 6 notes (pentatonic scale) per step. Bottom row enables random octave shifting for given step. Second row buttons enable echo from three notes back from current step.
Here is the code for the Geome sequencer.
This works pretty well. Not too glitchy. Would really like to be able to handle Trellis within an interrupt handler. That way it would be easier to implement midi clock signal, etc., as I am doing with some other projects.
Read More. Note: Video updated to most recent one as the previous two were removed.
Featured Adafruit Product!
Adafruit Trellis Monochrome Driver PCB for 4×4 Keypad & 3mm LEDs: This item is just for the Trellis driver PCB assembly: LEDs and buttons not included. Trellis is an open source backlight keypad driver system. It is easy to use, works with any 3mm LEDs and eight tiles can be tiled together on a shared I2C bus. This PCB is specially made to match the Adafruit 4×4 elastomer keypad. Each Trellis PCB has 4×4 pads and 4×4 matching spots for 3mm LEDs. The circuitry on-board handles the background key-presses and LED lighting for the 4×4 tile. However, it does not have any microcontroller or other ‘brains’ – an Arduino (or similar microcontroller) is required to control the Trellis to read the keypress data and let it know when to light up LEDs as desired. Each tile has an I2C-controlled LED sequencer and keypad reader already on it. The chip can control all 16 LEDs individually, turning them on or off. It cannot do grayscale or dimming. The same chip also reads any keypresses made with the rubber keypad. The connections are ‘diode multiplexed’ so you do not have to worry about “ghosting” when pressing multiple keys, each key is uniquely addressed. (read more)