(you don't need programming knowledge for building it) source code (c language) and compiled hex file for the uC will be posted here tomorrow.
and you need ... (things a bender has already) - some Resistors and capacitors - potentiometers and switches - 5Volt source (7805 voltage regulator) - breadboard or pre-drilled pcb
Thank you for your interest! I'm very motivated to continue the project.
sorry I forgot that pot values. The values for the 8 Potentiometers are not critical, use 10k Ohm Pots.
JP1 is the connection for the programmer (ICD = in circuit programming) You do not have to remove the PIC for programming.
And very IMPORTANT: the 100nF capacitor should be placed near as possible at the PIC ! (between pins 11/12 or 31/32), don't forget to power pins 11/12 AND 31/32.
The schematic is the minimum requierd. I want to keep it as simple as possible. But enough for the beginning. I don't think a ready made PCB is really needed. Of course we can add some switches, LEDs etc but then some more components needed...
I thoght long about selling ready programmed PICs, but what about software updates then. If you have a programmer you can do updates yourself.
Ordering a ready made programmer is a good idea (you know that thing is working). For my opinion the http://www.winpic800.com//index.php?option=com_content&task=blogcategory&id=19&Itemid=88 is a good choice because it can burn PIC , AVR and EEPROMs. And 60€ is not much for that feature. But there are also cheaper ones available (look for "ICD" or "PIC programmer" on google ... There are a lot other interesting PIC/AVR projects on the www like MIDIbox, SwinSID, AVRsynth etc... So it's nice to have a programmer for PICs and AVRs (the PIC and AVR microcontrollers are nearly the same, it's kinda religion which to choose)
If you not shure about the programmer you have found feel free to ask me. (the PIC18F4620 should be at least supported by the programmer!)
the sequence at the beginning is the dry signal out of the pic synth. i hadn't tweaked any knobs while recording. The sequence and tones came out of a "chaos algorithm"
at 6 seconds I added delay (digitech x-series digital delay) and filter(Korg MS20 filter unit). I don't know where the regular plops in the mp3 came from (maybe software bug or simply chaos itself
Just got my PIC programmer from somewhere in hong kong via ebay. It appears to program any PIC's up to 40 pin and EEPROM's. It also has a handy 6 pin connector so i can plug it straight into the PIC-synth board. Not bad for just under $10.
If anyone wants to make one of these synths in the UK, the only place i've found that stocks the PIC18F4620 in the UK is JPR electronics HERE
If anyone knows of elsewhere in the UK let me know.
If you can't find any distributor for the PIC18F4620, try DigiKey, Mouser ... or you can get free product samples from microchip.com if you register and have a little time.
Pot Description --------------------------------- 1 Algorithm 1..4 2 Speed / Pitch 3 Parameter 1 4 Parameter 2 5 Parameter 3 6 <not used yet> 7 <not used yet> 8 <not used yet>
Parameters 1..3 are depending on the algorithm. Parameter 3 is only used in Algorithm 3. Algorithm 4 is not working yet (available in next update)
Smal changes of the parameters can make big differences in the tones and sequences.
I'll keep you informed about software updates the algortihms can be more powerful ...
and some pictures of my prototype
Tip: If you build that thing in a box make a hole for the ICD programming interface. The 7805 voltage regulator can be very hot. Mount some "cooling metal plate" on it. Connect a LED (with 1k series resistor) to the 5V power supply to see if the power supply is working right.
each of the demo mp3 shows only 1 posibility what this thing does. I don't have tweaked any knobs while recording, only a external filter and delay fx were used. To make it a bit more exciting.
I have modified the first two algorithms from the first betaversion in order to make them more controllable.
Algorithm 1 fraktal synth, has 65535 posibilitys/different tones and sequences
Algorithm 2 fraktal synth, has 255*255*255 tweak settings... (different modulations than algorithm 1)
Algorithm 3 is preliminary, not very exciting
Algorithm 4 cellular automata, a bit buggy yet, but will be fixed
I'm planing to implement that "4 oscillator sleepdrone synth" as algorithm 3. (that thing build up from ttl/cmos buffers used as oscillators modulating each other) from Nicolas Collins book "Handmade Electronic Music: The Art of Hardware Hacking"
Both those new demos are briiliant, especially the first one, instant acid techno!
Its annoying that JPR won't have any of the right PIC's in stock until Feb 25th, i'm not sure i can wait that long, with any luck the samples i ordered will have arrived before then
What are you planning for the remaining knobs?
Some way of sync-ing the thing to an external clock input would be the most useful thing i can think of.
some algorithms will use all knobs (in the release version). I have added 8 knobs to be flexible, ok some are not used but I'm shure we find something to do with the unused ones It's better to have some left for future ideas (updates). For example I have combined the first two algorithms in one (7 knobs are used). Since they are pretty the same (mathematically).
Sync: mmmh... a bit difficult .... but should be not impossible timbre and sequencer are not created seperately (how it is done normaly) all result from only one algorithm. To tell the truth I hadn't thought about that a lot. But you are right that would be a good feature. I finish the 4 algorithms first and then I have a look how to do sync. MIDI (clock) sync?
Of course other PIC18Fxxx work for this project, too. But I don't want to rewrite the code for all possible PIC types available . I hope you understand that. But if it is really difficult to get the PIC18F4620 we can talk about using another more common available type. Why I have choosen the 18F4620: - lots of flash memory 64kByte (place for sample storage or something) - lots of RAM memory 4kByte - I had it already at home
I'm shure we could find a good distributor for the PIC...
« Last Edit: February 11, 2008, 04:35:04 PM by catweazle »
- Step-sequencer (8 step) with FM-tonegeneration... I discovered some TB-303 like stuff, no filter or other external equipment was used!! http://etecnic.fh-pforzheim.de/~catweazle/F-Synth/PICSynth_Fm-Stepsequencer.mp3 (step sequencer is controlled via two knobs one for step the other for the value at selected step)
No demo's are good! There's only one thing that matter.... how it sounds. And it sounds bloody amazing... why is that? what is it, 8 bit sound or 1 bit or what?
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picsynth.JPG
. I hope you understand that. 