MyCo

Hallo Freaks ;) Da ich ein neues und etwas kostspieliges Projekt plane, muß ich mich wohl von meinem 1. Eigenbau-Midi-Controller trennen. Ich habe keine konkrete Preisvorstellung, daher bietet mir einfach was an und ich entscheide ob es sich für mich lohnt. Das Angebot richtet sich nur an Interessenten aus Deutschland, ein Versand in andere Länder ist aufgrund der Größe und des Gewichts einfach nicht möglich. Ich verkaufe es außerdem nur an Bastler, da ich keinerlei Garantie auf meine Baukunst geben kann und ein Support für Elektronik-Noobs kann ich aus Zeitgründen nicht machen. Das Gerät funktionierte bisher einwandfrei, ich verwendete es allerdings ausschließlich in Fruityloops... Was unbedingt erwähnt werden sollte: Das Gerät ist nicht Midibox-Hardware-kompatibel, wenn man es also mit MIOS steuern möchte, muß man etwa 80% der Hardware austauschen. Hier die Eckdaten: 61 Fullsize Keyboardtastatur, Key-Scan-Matrix, Gumminoppenlagerung auf PCB 128!!! Drehgeber, Bourns, 24 rastende Schritte, mit Tastfunktion! 128 Tasten (die in den Drehgebern) 128 Aluminium Drehknöpfe 2x20 Zeichen LCD mit Hintergrundbeleuchtung, "busy" ist angeschlossen, daher sehr geringe Reaktionszeit 4 Menü-Taster, 3 davon werden auch als Transport verwendet (Play, Stop,Resume) Atmega128 auf Träger-PCB mit 16MHz Quarz, nahezu jedes Pin ist belegt :D Programmiert in Bascom Basic, daher sehr leicht zu verstehen/Programmieren 3 Digitaleingansplatinen mit je 128 digitalen Eingängen, 2 davon sind professionell gefertigte PCBs mit Lötstop und Bedruckung, sind NICHT DIN kompatibel externes Netzteil Zur Bauweise: Das Gehäuse war ursprünglich von einem Keyboard, die komplette Oberseite wurde entfernt, und stattdessen eine 7mm Laminat-Platte mit Epoxid-Harz eingeklebt. Alle Bedienelemente wurden auf der Rückseite der Laminat-Platte befestigt, daher sind auf der Oberseite keine Schrauben zu sehen. Alle Löcher die an der Rückseite für Anschlüsse waren wurden mit Spachtelmasse geschlossen (davon ist von außen nichts zu sehen). Anschließend wurde das obere Gehäuseteil rund 20 mal geschliffen und lackiert, es ist also spiegelglatt und hochglänzend. Im Inneren sind die Bedienelemente (also die Drehgeber) auf eigenen Lochrasterplatinen. Die Verbindung zu den 3 DIN-Platinen erfolgt über Litzen (immer 4 gruppiert) und gekrimpten! Steckkontakten... dadurch wurden mehrere Kilometer an Litzen verbaut. Ich mußte einiges durch experimentieren ändern, zB. mußte ich nachträglich die Load und Shift-Signale der DIN Module verstärken, weil deren Leistung für 48 Stück 74hc165 nicht ausreichte. Nun, hier sind die Bilder: Fragen dazu könnt ihr hier stellen, oder direkt an mich, per ICQ: 53-216-558 MfG Maik

ok, here is the version without postprocessing (except normalization): http://yedey.com/other/filtertest_org.mp3 20% of the noise in there is from my PC (I use the soundcard from the mainboard, which is noisy) the other 80% are from the synth. I found out, that most of the synth noise comes from the midi input, that means, as soon as I send a midi message, I can hear a noise. The clip above uses 3 automations, so there are a lot of midi messages which generate a lot of the noise. I think I've to put some more capacitors on the board to filter the voltage drops of midi in optocoupler...

So, here is the first preview. I've finished my first attempt to build in a filter... http://yedey.com/other/filtertest.mp3 It demonstrates the filter (cutoff & resonance) and wave morphing from saw to square. It already has 7 different waveforms and it can morph between all major waveforms (sine, saw,square triangle). The filter introduces a lot of noise, which I tried to kill in the DAW.

Yes, I make it open source. But at the moment I don't have a schematic, because it is so simple, that I draw the connections directly in a PCB-Layout programm before I built it :) To program the AVR, I use an In-System-Programmer (Flat cable on the left) with PonyProg, and AVR Studio 4 to write/compile the Assembler. All of this parts are Open Source / Freeware, too.

I've been working on my version of an AVR Synth. Now it looks like this: The only addition to get it running is a power supply, I've built my own: Total investment: 16 Euro and ~100 hours til now The AVR is an Atmega644 running at 20MHz (the crystal and its caps are under the chip), so now I've 64kB of Flash memory and I use 16kB of it for a wavetable. At the moment it sounds like nothing. I'll come back when I've got something to listen to it ;)

Sorry, that I answer so late. Why I don't get a mail when something's posted here... @mess: At the moment the R2R-Ladder-Network DAC performs best. You don't need any filtering at the end, but a buffer OpAmp. To be 100% correct you need to shift the voltage from the range 0 to 5V down to -2.5 to 2.5V. If you only use speakers or headphones, this is no problem...but if you want to record it For the IC-DACs I use a simple LP-Filter (Capacicator to ground and an OpAmp to raise the level again)

That's how my tests look like... at the moment: I've several dac modules... just for testing...

You could replace the MAX525 with a 74HC595 and a DAC 08 (or DAC 0800, DAC 0832) total costs for this would be 3 Euro (eg. @reichelt). Accuracy would be +/-1 LSB and with a DAC 0830 LCN you can get a linearity error less then 0.1% of the fullscale which would be 10mV... with an additional lowpass filter and a good opamp eg. OP 27 it would be a perfect replacement

Well, I'm just working on the same project, but I use a AVR instead of a PIC. The way with PWM is nice and cheap. If you use a big Cap on the output, you can also use the pwm modulation amount as direct analog DAC output. Soundgin and Speakjet do it exactly that way. I've bought some DACs (0832) for my project, but the hardware part get's bigger and bigger, because you also need some OpAmps and that is realy bad: negative voltage.

I don't know all optocouplers on market, but I think that there is no one that can switch a car light. If the light has 12W that means it takes 1A and that is too much for the optocouplers that I know. To the fan thing: If the fan has a tempo signal like most of the computer fans, you can count the triggers per second, and you'll know the speed. That is something for a microcontroller. Displaying the result on an LCD is also no problem for a µC. A µC can als control the speed of the fan, in a good, clean and easy way: Pulse width modulation. For the whole thing you would only nead a simple µC-Testboard with voltage regulator, a transistor and some resistors. That makes 30$ (LCD incl.). I guess it is cheaper in US. To the LM3914: It has an adjustable reference input (that's pin 8 ), which has to be adjusted to work correctly. Just take a look on ebay, there are some Atmel testboards, with LCD and sometimes with relais, so you could do everything you've descibed on a single board just by adding source code.

Why don't you use something simple stuff like this: Has the same result, is cheap, and you don't have clicking relais.

That is not that easy to explain. You need a schematic for that, but I've no drawing program at the moment, but basicaly: The or gate output must be connected to the base of a transistor, this is connected with emiter to ground , and collector to relais. The other side of the relais is connected to 5V. Parallel to the relais should be a diode to safe the electronics. But there come different things you need to clear: The transistor must be "big" enough to drive the relais without overheading or burning down. The relais must switch at 3-5V (there are different relais on market). Also the whole thing needs a stabiliced power source. Your cap won't work, because when the relais switches on, the input voltage of the circuit will break down, and the logic gate would clear... so you'll get a permant relais switching. To be 100% correct, you would also need some resistors, eg pullups or pulldowns, resistor base driving resistors... It is not so easy...

ich habe meine Teile alle von www.reichelt.de www.kessler-elektronik.de www.pollin.de und die Encoder sind Amerikanische Importe Das war ursprünglich ein einfaches Keyboard. Ich habe da einfach die Oberseite ausgeschnitten, eine Laminatplatte mit Epoxyd eingeklept und mit Spachtelmasse aus'm Baumarkt geglättet und dann lackiert. So hat es vorher ausgesehen:

Hallo! Also für 24 Drehregler und 8 Fader benötigst du: 1x Core (ca. 15 Euro) 1x AINx4 (ca. 5 Euro) 24x Poti + 24 Kappen (ca. 35 Euro) 8x Fader + 8x Kappen (ca. 10 Euro) Dazu kommen Kleinteile und jede Menge unerwartete Kosten für Kabel, Steckverbinder, Platinen, Halterungen, Kabelbinder, Case... da würde ich mit ca. 50 Euro rechnen macht ca. 115 Euro... Und wenn es Luxeriöser sein soll, kommen noch LCD und USB dazu... Man sollte die anfallenden Kosten nicht unterschätzen... das ist mir auch bei meinem Controller passiert. Mein Midicontroller hat 128 Encoder, 128 Buttons, 62er Keyboard-Tastatur... die Kosten habe ich auf ca. 300 Euro geschätzt. Durch die ganzen zusätzlichen Kosten, habe ich jetzt schon mehr als das doppelte ausgegeben... Allein für Versandkosten habe ich schon fast 50 Euro ausgegeben. MfG Maik

try this: http://www.ryston.cz/pdf/display/display.pdf seems to be the same product line, so it could be pin compatible

You could solve it digitaly. Just use the string as ground and connect the frets to DIN... then you only need the firmware...

The idea of using pwm as analog output is good, but I guess that there are a lot of errors in the signal, because the caps may be to slow. I don't know, I'd never tried it. I'm working on my selfmade testboards with AVR at the moment. I think it is possible, to generate waveforms with 1 AVR, and without an external EEPROM. When I use the slowest prescale timer, I can get a sampling rate around 16kHz and have 1024 cpu cycles to generate each sample. When I use precalculated waves from the internal EPROM or SRAM, I guess that works. I've seen PICs with 40MHz. When an AVR isn't enough, then these PICs may be the solution. My biggest problem is the DAC. I've around 20 DACs flying arround, but I'd never get one to do what it should do ;D

der Vee Pin wird an den Regelbaren Widerstand zur Kontrastregelung angeschlossen. Ist bei dem Core V0. Ich habe hier irgendwo gelesen, dass man bei einigen LCDs von Reichelt eine negative Spannung an Vee benötigt, damit der Kontrast ausreichend wird. Evtl. trifft es bei deinem LCD auch zu. Denn normalerweisse ist V0 im Datenblatt angegeben.

Geht das Backlight denn an? Wenn nicht haste vielleicht die Anschlusspins falsch durchnummeriert

Hi! It's saturday, I'd nothing to do, so I brought some ideas to paper: This is my concept of a modular hybrid synthesizer using 3 PIC, EPROM and some cheap logic and analog components. I think that works fine, and the PICs have much time to calculate their parts. How it should work: Each µC-Board listens to the same midiconnection, and each of them use only the data it needs, eg board 1 only takes note-on and note-off events. Each board calculates independently. The PIC on board 2 uses the timer to read the input and to output the results. Board 3 & AOUT are the things TK made already. The clock generator is basicaly a downcounter with 2 latches using a high frequency crystal to work. There is a similar board here: http://www.cgs.synth.net/modules/cgs20_dco.html The wavetable is an EPROM driven by a counter, similar to this: http://www.cgs.synth.net/modules/wavetable.html VCF ... I don't know, there are a lot of schematics... DAC is simple IC, eg DAC0830, DAC0832... So, what do you professionals ;D think about it? Does it work, or am I wrong? It is a modular hybrid wavetable synthesizer, you could add additional digital parts between board 2 and the DAC, you could also add analog parts between DAC and VCF... I guess it would be realy cool, if it works that way ;D THX Maik

I only use bypass caps on µC... on simple logic ICs they are pretty useless... may be that I'll use one for each board By the way, I found out that my board has a big disadvantage... I'd to make 32 cables for each board...that's a stupid work ;D Next time I'll route all input pins to one big connector, with only one 5V-supply-pin (on your board it would be ground).

Hi ! I'm new on this site, and have some questions about the DIN Module. I made my own before I checked the schematics from this site, and it is a little bit different: so the questions are: 1. Why don't you use Resistor-Networks? They are easy to handle, and reduce the board size. 2. Is it better to use pullup instead of pulldown resistors on the input of 74hc165? Thanks Maik