Hans-Christoph Steiner wrote:
On Nov 6, 2006, at 6:42 PM, Martin Peach wrote:
Chuckk Hubbard wrote:
I'm going forward with this Moog-controlling plan. I have Pd on my laptop, and have compiled [comport]. I'm not sure how to use it, though. As with so many things, most of the info I can find online tells me way more than what I want.
What I want: Is it possible to send constant values OR individual bits to the serial port, as opposed to bytes separated by on/off bits? How can I set up the timing on this to send controllable PWM? Will it be possible to send PWM from comport with -noaudio?
You can toggle the handshaking lines at high speed but you will run
into the jitter caused by pd's audio block size. Or you could send
data through the serial port with different ratios of on and off
bits, but you will only get 8 different levels. I think you need to
put a serial dac there. It's possible to clock serial data into a
dac using just the handshaking lines -- one serves as a clock and
the other data.That's an idea for an object written in pd [serial-pwm]. It would
PWM signals by flipping bits on the serial port. Frequency would be
determined by a combo of baud rate and bits used for one cycle.Hmm, I wonder if it would be useful at all...
.hc
I'm not an expert in electronics. But I believe that this should need a microcontroller.
You send the notes you want to play via serial port to the microcontroller, which sends a pwm signal that can be flattened with a simple rc circuit (a condenser and a resistor).
I've done this some years ago to control my Korg MS20. I've used an IC (Max232, IIRC) and the PIC 16f84a. It costed less than 5 EURO in parts.
There are plenty of ready made projects and schematics for this task (just google for it).
Ciao,
c.
The arc of history bends towards justice. - Dr. Martin Luther
King, Jr.
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