On Sun, 27 Oct 2002 11:19:15 -0800 (PST) Matthew Dillon <[EMAIL PROTECTED]> wrote:
> > : > :Shouldn't the fact that the signal is in a while loop keep the 5 volt > :signal going? Isn't the parallel port being blasted with the > :value 255 over and over again? > : > :The serial port will not fulfill what i am ultimately trying to achive. I > :am trying to have the parallel port to control 8 relays each turing > :on/off based upon which bit i send out to the port. > : > :.. > :> try using also the serial port and a logical buffer > :> > :> the 5 volt signal is very fast and your multimeter is maybe not to fast > :> > :> > I'm looking for a 5 volt signal. > > Uh guys. Parallel port digital outputs do not generally have a whole > lot of drive. I really doubt a parallel port output could drive a > relay. > > And it's probably TTL level equivalents, not CMOS. Even if you ganged > the output bits together I doubt you would get enough drive out of > them. > > A serial port output (+/-12 but you may see +/-10 or -5 and +12 or other > out-of-spec combinations) is far more likely to be useful in driving > a relay, though again there will not be much drive. It would be far > better to supply the power you need from another source, like a +5V > power supply. Or just get a wallwart with DC output and run it through > a linear regulator. At least then you aren't likely to burn the house > down :-) > > -Matt > > To Unsubscribe: send mail to [EMAIL PROTECTED] > with "unsubscribe freebsd-hackers" in the body of the message > Two things here... One, most multimeters do not have the senistivity to monitor a pulse like this, they will just see 0 volts. You really need a scope or a probe to see this. Second, you'll can't drive an analog relay off of Pport without a latch or something. A transistor setup would work just fine. Check out http://www.circuitcellar.com/ for stuff that would work... GB -- GB Clark II | Roaming FreeBSD Admin [EMAIL PROTECTED] | General Geek CTHULU for President - Why choose the lesser of two evils? To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
