MidiALF

MidiALF is an 8 step DIY friendly MIDI/CV sequencer with 40×2 LCD, 8+2 clickable rotary encoders, 8 LED switches and 8 tactile switches.

MidiALFCV_naked_(small)

MidiALFCV_done_(small)

Manual

Build instructions

Troubleshooting

Ordering

Latest firmware: midialf_v095

Features

8 steps in 4 sub-sequences which could be linked as two 16 step sub-sequences or one 32 step sequence.

Each sequence contains 10 tracks:

  • note/mute
  • velocity/skip
  • gate/legato
  • CC1/send
  • CC2/send

Sequence direction: forward, backward, pendulum, random.

Nonlinear sequence progression modes (same as in MIDIBox SEQ v4):

  • forward, backward, replay
  • interval, repeat, skip

Super stable internal clock based on Mutable Instruments MIDIpal technology, 25-250 BPM.

Two assignable CC LFOs with the period of up to 2 bars and sync to start, sequence and step in addition to free running.

Real-time and step recording modes: records notes, velocity, legato and CC1/CC2 values.

Sequence and step randomization using 167 music scales (thanks to MIDIbox.org).

Internal storage for 256 programs each containing 4 sequences with setup parameters and 16 character name.

Sysex send/receive of sequence, program or all programs.

Remote control with CC.

Optional CV extension board: adds 4 x CV an 4 x Gate outputs.

Firmware upgradable by SysEx.

Midi only variant is powered by external 7.5 – 9V DC power supply, center pin positive, minimum 300mA. MidiALF/CV variant needs 16VAC AC power supply.

DIY Resources

Schematics: alfsch#1 alfsch#2 alfsch#3

MidiALF_brd

Eagle .sch/.brd files and v0.92 firmware .hex files files are available here.

Bill of materials.

Source code: MidiALF_094b_src

PCB and MCU

You can purchase MidiALF main board directly from me for US$35.00 and pre-programmed ATmega644p MCU for US$15.00. The CV extension board is US$30. The prices do not include shipping from California, USA. PayPal payments only.

Case

Frank Daniels  provides standard or customized acrylic case with mounting accessories for 65€ plus 8€ shipping from Germany. Email  daniels (funnyashapedcharacter) daniels-cards (spotofdirt) de.

MidiALF_plexi

Acknowledgements

MidiALF is built around technology developed by Mutable Instruments: most of its hardware components can be found in various MI’s projects (mostly Shruthi-1 and Ambika), while software implementation uses quite a lot of code from MIDIpal. Not to mention the breakthrough Avril programming framework that brought modern C++ programming (read: productivity and sanity) to Atmel MCU world. Without this MidiALF project would not be possible, so thank you, Olivier, for sharing your talent with all of us!

I’d also like to thank Thorsten Klose of MIDIbox.org for his kind permission to use music scale definitions and non-linear sequencer progression modes found in MIDIbox SEQ v4.

201 thoughts on “MidiALF

  1. Is there a way to change gate polarity per step in the gate page as opposed to changing the polarity on the cv/gate output page? I’m looking to engage/disengage switches via the sequencer.

    • I’m not sure I understand your problem: gate polarity setting only changes the meaning of on and off states normal ( off is low, on is high) to inverted (off is high, on is low). It does not make any sense to change this setting per step.

      • I think I was having an issue getting the gate to trigger in this case the echo cancel input of a Roland space echo. I think the issue was the velocity was set to zero. When the velocity is above 0, the gate seems to work fine.

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