SynthFrog » midibox

Mr. Braska at MidiBox HeadQuarters!

admin — Tue, 16 Mar 2010 21:49:44 +0000

Mr. Braska reached MIDIbox HQ in Munich and was welcomed by Thorsten aka. TK with a traditional wheat beer and a nice midibox.org sticker as a present.

The little frog was very excited to sit on the famous original MIDIbox SID prototype that he only knew from pictures before:

He quickly jumped to one of his most favorite knobs and started to tweak on a lovely bassline. He was completely stunned from the unique SID sounds:

And he couldn’t resist to program a suitable drum sequence:

Of course, he also wanted to get his hands on the brilliant MB-6582 design which TK got as a present from Wilba:

And the MB-808 that evolved from a joint work with Moogah:

It was late in the evening, and Mr. Braska swinged into a sweet slumber, curious about the other projects that he will explore in the next days.

Midi2CV Part 1

aris — Wed, 29 Apr 2009 18:09:00 +0000

This is a module for my synth. A pretty basic module as it is a note to Control voltage converter. It is based on midibox ucapps.de designs and it features 4 CV and 4 gate outputs. These can be made 8 bits which are quite good for note playing (4 x 8 bits) or can be made 4 and 12 bits each pair. I chose to have them all at 8 bits resolution.. The circuit is ready and it needs a panel (which you see in the photos) and some wiring an mounting

I used a long screw I found in the hardware store. It was a one meter , 3mm width screw which I cut at around 17 cm pieces. Then glued a nut on the panel with instant glue and put resin glue on top of it. Put the screw so now the nuts are filled with resin glue.

You can see here the resin . To align the screws, I fixed the other sides of the screws on a board .

A working SID Synth

aris — Mon, 30 Mar 2009 20:00:00 +0000

The SID synth is working!

As I just bought a simple oscilloscope, wave shots follow..

The SID filter works by using two capacitors. I think it works by switching them on and off in sequence. However it works internally, you can experiment with the values of the capacitors. So to experiment without solder/desolder I put a pin header.

So:

The saw

The triangle

The pulse

The noise

The filtered saw with lots of resonance

Now on to a casing.. I had some ideas. But I would like first to get my hands on something to realize it.. Patience is a virtue. I am no virtual, I am real (I think

Sowing the SIDs of love

aris — Fri, 13 Mar 2009 07:53:00 +0000

All things come to those who wait. But even if you wait for an eternity, no SID will come your way unless you hunt it down because it has been long since it was discontinued! And so I did hunt it!!. Two found and thus, the quest for the MidiBox SID began.

It is a stereo SID synth. Two sids, one for each channel. Made the Core (the old 8 bit), got two 18f4685 (of which I toasted one because I gave it 12 volts!! Thank god I got two) made the boards and TADAAA!!!!

The SID works!! If you play something via midi you get a square lead sound.. nothing special but it is there.. So now I must add buttons and encoders.

The only thing that went wrong apart from the burnt PIC was that the 20×4 blue/white screen I had to put , went cookoo!! Maybe this was a result of the 12 volt jolt! But, no real harm done since I have a spare 40×2 screen.!!

Now I REALLY have to finish the midibox router and midibox sequencer.. I have no excuse, neither does Braska!!

Midibox Day

aris — Wed, 11 Mar 2009 09:00:00 +0000

This is the day of the midibox. I started making 4 MidiIIC modules and 4 Core Modules (pic based)
The four MidiIIC will be used for a midi router (again, a midibox project) I am making.
One of the cores will be used for it too. The other one will be used for a SID engine (with TWO sids!! Stereo!)
(I already found the SIDS). The other two core modules will be used for various experiments and to continue
the (delayed) development of the harmonic table project. Of course Braska is here to help!!!!

IT’S ALIVE!!

aris — Sun, 30 Nov 2008 22:53:00 +0000

The connections have been made and some simple software has been written to map keys to notes. There are some issues that need to be sorted like transpose while pressing keys etc. The concept works! It is a very nice and cheap way to experiment with such a keyboard.

It feels a little flimsy though, pressing buttons against an unsupported perfboard so the top priority now is to find a case that will make the keyboard right at home! I will add some knobs too. There is much (programming) space for them

So, stay tuned for a first video demo as soon as possible. The only thing I need right now, is a little practice!

The proof of concept

aris — Wed, 26 Nov 2008 23:24:00 +0000

This is the keyboard from the last post with some additional stuff. There is a Core module (midibox.org) and a digital in midibox module that reads the switches. I installed the SDK so I can write a minimal program (midibox is programmed in C and produces hex files, uploadable as system exclusive data to the core). So I connected 4 of the switches to make a quick test and connected them all together. I was sure that both midibox modules were ok because I had the midibox sequencer running on them. The simplistic program just adds 40 to the pin number (the one displayed on the LCD) and outputs this as a note on/off midi signal. When all switches get connected, there will be a need for a mapping between module pins and note numbers so there will be some more programming. For now, a small, quickly made video shows that IT WORKS!

(first video for public viewing, so don’t be so harsh

You can also see it in vimeo here: http://vimeo.com/2357167

Harmonic table keyboard

aris — Tue, 25 Nov 2008 22:35:00 +0000

This is another project I just started working on. It is a keyboard/MIDI controler based on the harmonic table (like the c-thru music controler). This one is just switches which all connect to a midi core module (from ucapps.de) which translates the various keypresses to midi signals. There are 50 keys/notes and although I’m going to use letra-set rub-ons to write the notes onto the keys, you can make out which note is which from the blue keys. They are in pairs and one of each pair (the low/right) is an A (La for europeans) and the other is a C (Do). In the harmonic table layout that the C-thru axis uses (and others) , if you choose one button, the button above it is a fifth, the one to the top/right a minor third and the top/left a major third. (you can see c-thru’s chord calculator here http://www.c-thru-music.com/cgi/?page=layout_ccalc).

The other keys have the following functions: The red keys on Braska’s left “hand” are a row of 11 buttons that instantly transpose
the whole keyboard from -6 to +5 semitones The middle one, a bit spaced appart, is the no-transpose button. The other 2 red buttons are octave up/down and there is a generic slider under his right hand which is assignable to modulation, pitch bend or whatever CC you want. The blue button under his belly is the menu button. There is a 16×2 LCD screen displaying various bits (transpose, octave, pressed key etc) but the software is still in development stage. As soon as a workable version is at hand, I will publish it of course.

The needed hardware is a lot of switches, a midibox core module, an analog in module (for the slider) and two digital in modules for the switches. I have these already made for the midibox sequencer (who still lacks a panel) until I etch some more. http://synth-diy.blogspot.com/2008/10/midibox-sequencer-v33.html

So the following days will hopefuly see a working HT controller. But until then, good night, Braska!

STAY AT 440 Hz!!!!

Switches!!!!

aris — Thu, 06 Nov 2008 21:57:00 +0000

Switches came. Tact switches for many purposes… The midibox Seq waits for some of them. The c-music axis clone, for most of them, and maybe a mini keyboard for one of the synths. Hey you could even make a guitar fretboard with them, they are just the right size.

For making stuff with switches, midibox ruleZ!!!!

MidiBox Sequencer V3.3

aris — Thu, 23 Oct 2008 11:04:00 +0000

These are the core components, etched, soldered, placed, programmed, working, but lacking a nice panel to sit on. This is my weak spot. .. Panels…

A big thanks to T. Klose and ucapps.de for exisiting