[PD] comport and servos

[Martin Peach]

Piotr Majdak wrote:
> Hi Martin,
>
> Martin Peach wrote:
>> I suppose a [comport~] object could use a signal inlet for some kind 
>> of trigger to send a message that was set up on another inlet...any 
>> suggestions?
>
> A stupid question: why don't you use the printer port? You can control 
> 8 digitial inputs/outputs there...
>
Well for one, most laptops don't have parallel ports. Two, accessing the 
parallel port is problematic on recent versions of Windows. For some 
reason Microsoft thinks parallel ports are dangerous potential hazards 
and only those who can afford drivers should be allowed to access them. 
I don't know if a free-in-every-sense driver exists that could be 
incorporated into a pd external without issues, and I don't feel like 
writing one, it just seems like way too much work for nothing.
Three, the parallel port will have the same timing problems as the 
serial port from pd: messages are handled between audio blocks so 
sub-millisecond timing is  not really feasible.
I myself find it much easier to build a circuit with a PIC 
microcontroller and a MIDI interface. I can precisely control 8 or more 
servos that way. (I can provide circuit diagram and code for anyone 
who's interested, for a few dollars more can program PICs as well...but 
you can also buy serial servo controllers for the price of a servo, like 
this: http://www.seetron.com/ssc.htm
that also uses a PIC.)

Martin
> br, Piotr
>
>