You can't miss a LED Matrix displaying messages. It's an excellent way of broadcasting your name/website/instagram etc. whilst gigging. In addition to displaying scrolling messages, this design syncs to a MIDI clock displaying animations in a 4/4 beat fashion. 4 RGB LEDs change colour at random interval to attract even more attention. Please make sure the following Arduino libraries are available:
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MD_Parola.h•
MD_MAX72xx.h•
SPI.h
Video 1 - Modes & Selecting Messages (no sound)
0:00-0:21 - Message only. Switching from Message #1 to #3.
0:21-0:50 - MIDI only.
0:50-1:57 - Auto-alternate between MIDI only and Message only (30 sec. interval).
Video 2 - Gigging impression
0:00-0:15 - Message only Mode.
0:15-0:51 - Switiching to MIDI only. The MidiMatrix automatically switches to MIDI only mode right after it finishes the scrolling message at 0:25 (the hi-hat kicking in is coincidental).
0:51-1:35 - Switching to MSG/MIDI mode. Here, the MidiMatrix automatically alternates between MSG- and MIDI- mode.

Coding your own messages is easy. See below; just open the Arduino sketch with the Arduino Software (IDE) and edit any of the three defaults messages ("Text Message 1", "Text Message 2", "Text Message 3").
Tap Icon to download the schematics, components list, PCB stripboard- & frontpanel- designs. Print the frontpanel page out to actual size on (Purple) A4 sticky peel self adhesive paper.
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This design is inspired by the Proco RAT and Valve caster products; in fact, this build combines both circuits for an extra fat bass sound. I designed the circuit for the Cyclone TT-303 Bass Bot (the best TB-303 clone out there) and Korg Volca Bass. The Warp Factor toggle-switch switches between diode-types to alter the characteristics of the sound.

Tap Icon to download the schematics, components list, PCB stripboard- & frontpanel- designs. Print the frontpanel page out to actual size on (Purple) A4 sticky peel self adhesive paper.
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Schematic |
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Frontpanel |
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PCB |
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Components |
Photos
I like the Korg Volca series especially the Volca Bass. I also like the TT-303 (TB-303 clone). They sound fantastic and are a great addition to any synth jam session. If, however, you like to create EDM, the one element you need is a pumping bassline by feeding an audio signal through a compressor and apply side chaining. But that can take quite a bit of time in setting up and keeping it running smoothly (as you need a steady audio kick to feed the side chain). So, I thought of approaching things from a different angle; what about passing audio through VCAs and drive these VCAs by means of an Arduino and, in turn, a Digital to Analog converter driving the VCAs. This project, The Bouncer, does exactly that. The Arduino runs in sync with a MIDI clock and you have two dials (Bounce & Grit) two tweak the pattern of volume modulation. Please watch the youtube video below to get an idea. The effect is perhaps not immediately noticeable but it's certainly there. Towards the end (3:40) the Bounce/Grit settings are more extreme and the volume-modulation is clearly audible (like the bass is running in reverse).
This project is based around the SSM2164 (quad VCA). Two VCAs process a mono signal each (like the Volca bass and TT-303). The remaining two VCAs process a single stereo signal; this could be the Volca FM for example. There is a fourth stereo channel, which is just a pass through into the mixer stage; this could be the drum section such as the Volca Sample.
I put this project in a semi-translucent box and thought it would be cool to add two internal tri-colour LEDs in there for a nice visual (as the Arduino has plenty of I/O to play with).
The Bouncer also has Gate & CV out to drive a Eurorack. The Gate sends 5V trigger pulses at 4/4 and the CV is a duplicate of the control voltage driving the internal VCAs (visualised by the large LED next to the Bounce dial).
Oh, and last but not least; with so many Volca boxes around, it would be good to have a few MIDI patch points - so, I added 3 x MIDI THRU. Enjoy!

Tap Icon to download the schematics, software(Arduino Sketches), components list, PCB stripboard- & frontpanel- designs. Print the frontpanel page out to actual size on A4 sticky peel self adhesive paper.
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Schematic |
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Software/Sketch |
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Frontpanel |
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PCB |
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Components |
Photos
This master clock broadcasts 4 MIDI clocks, which can be stopped/started independently. In addition, each of the 4 start/stop boxes provides DIN Sync (24/12/8/3/2/1/.5/.125 PPQN). There's also an I/O socket on each box for you to play with if you are interested in changing the Arduino sketch. This MIDI clock design also has 3 MIDI inputs; each input passes on MIDI data to all for start/stop boxes except for timing messages (so sync is not messed up by external midi clocks). This MIDI clock is aimed for people to collaborate and run well synced jam-sessions.



Tap Icon to download the schematics, software(Arduino Sketches), components list, PCB stripboard- & frontpanel- designs. The frontpanel .pdf contains 5 identical drawings; please print this page out to actual size on A4 sticky peel self adhesive paper.
Schematic #1, Software/Sketch #1 &Frontpanel #1a etc. is the main clock with all four MIDI outputs controlled from one box; if, however, you want each clock to be distributed and controlled further away from the main clock & if you want to add analoge DIN sync., then you'll need to add Schematic #2, Software/Sketch #2 &Frontpanel #2 etc.
The main clock uses an Arduino Mega. The distribution boxes each house an Arduino Nano.
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Schematic #1 |
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Software/Sketch #1 |
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Frontpanel #1a |
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PCB #1 |
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Frontpanel #1b |
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Schematic #2 |
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Software/Sketch #2 |
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Frontpanel #2a |
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PCB #2 |
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Frontpanel #2b |
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Frontpanel #2c |
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Frontpanel #2d |
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Frontpanel #2e |
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Frontpanel #2f |
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Frontpanel #2g |
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Frontpanel #2h |
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Frontpanel #2i |
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The DIY design below is one of those must-have modules. This module has two independent LFOs. The third output is effectively the sum of the two individual LFOs. This third output produces some very random voltages, which can be even-out by means of the 'Glide' dial.
Tap Icon to download the schematic, components list, PCB stripboard- & frontpanel- designs. The frontpanel .pdf contains 5 identical drawings; please print this page out to actual size on A4 sticky peel self adhesive paper.
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Components |
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PCB |
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Frontpanel |
Photos
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Tableau Network Visualisations.