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I'm sorry to ask this but I don't know anything about electronic part and I need this setup for my mp3car.
what kind of electronic part do I need if I want just 0.5 pulse output when the neg or pos power input ? (just like used in car alarm)
thank you for your help, guys.
0.5 seconds or 0.5 volts out, would something like a 555 work? what exactly are you trying to do?
Rob
I'm trying to use parallel port controller to control some car switches.(such as door , alarm , and more)
the problem is the controller is just relays , it can only turn on or off constant power. But for example , a door switch needs short pulse power (0.5 or 1 sec) .
And I was wondering if there is a simple way to make this work. ??
any idea???
A 555 is a very cheap all in one timer chip that can be used in various modes, including one shot (monostable), ie when a signal is applied on it fires a single pulse which lasts for X sec. The lenght of the pulse is controlled bu two support components (a resistor and a capactior).
See this site for more info on 555 chips.
Figure 9a is probably what your after
Rob
huh? I don't get your problem, if you have relays connected to your PC you can program your PC so that it turns on your relay and 0.5 sec later turns the relay back off??