Rhythm generator

[Fraser, Colin J]

> -----Original Message-----
> From: Stewart Pye [mailto:stew at uq.net.au]
> Sent: 15 April 1999 15:05
> To: WJ Bland
> Cc: synth-diy at mailhost.bpa.nl
> Subject: Re: Rhythm generator
> 
> It might seem daunting at first but I think a microcontroller 
> is really the
> way to go for this kind of project. These are my reasons why:
> 
> 1. minimal amount of switches needed. (606 style programming)
> 2. switches can be software debounced.
> 3. less wiring
> 4. lower cost
> 5. less wiring!
> 6. ability to store patterns.
> 7. you can have built in midi sync if you want it.
> 

I agree with the above, but if the thought of programming your own rhythm
machine fills you with fear and dread, you could always buy a TR606
processor from Roland. They have these in stock in the UK for 12ukp. You can
download the schematics off the web, and just build the sequencer part.

I know a man who built a clone of the 303 including an original 303
processor for the sequencer section.
I have a set of his PCBs for the sequencer section of the 303 at home, but
unfortunately the 303 processors are gone.
One day I'll reverse engineer a replacement for it.
Just as soon as I decide whether to go down the Atmel or Microchip path...

The project I'm working on at the moment is combined rhythm sequencer and
analogue style step sequencer.
It has a row of 16 buttons x0x style, with a row of tricolour leds above
them, then two rows of 16 pots.
To the side is a 9 key pad, and a 16x2 line LCD display (which I blew up
last night :-( )
For drum patterns, the buttons turn each step off or on, one of the pots
will adjust the velocity, and the other the beat delay for that step (for
shuffle).
The tricolour leds indicate accent level by changing from red thru yellow to
green.
Note patterns use both pots to set note and either velocity, gate length or
delay. The buttons can turn notes and slide on or off.
This is initially being written around a 6502, but when I finish it I will
port it for whichever microcontroller family I choose.
If you can wait a couple of months, I should have schematics and source code
available.


Colin f