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Thread: help to design a timer circuit

  1. #11
    Raw Wave rando's Avatar
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    Quote Originally Posted by CdRsKuLL
    I'm after a 20 second timer, this is going to be used to delay the turn on of my amp. I will be using the 12v line from my opus to trigger the timer, and the ACC line from the car as the main feed to my amp.. so really a relay and something that waits for 20sec's before it passes the signal.. I dont know much about electronic's.. but i'm ok with a soldering iron.. please help

    cheers

    CdR
    I assume this means you only want your Amp to come on after your computer has had time to boot. Is that right? If so, you can use a serial or parallel port pin to switch your relay. That way your amp on/off could be controlled programatically (by timer or otherwise). All you need is a relay, an optional optical-coupler, a transistor and a few passive parts.

  2. #12
    Low Bitrate nrls2000's Avatar
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    Quote Originally Posted by rando
    I assume this means you only want your Amp to come on after your computer has had time to boot. Is that right? If so, you can use a serial or parallel port pin to switch your relay. That way your amp on/off could be controlled programatically (by timer or otherwise). All you need is a relay, an optional optical-coupler, a transistor and a few passive parts.
    can this programatically turn amps on as soon as audio signal is present or is it only timer based?

    I am interested in audio signal turn on circuit over timer relay circuit.

  3. #13
    What can I say? I like serial. Curiosity's Avatar
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    If done through the serial port (or LPT or whatever), it can go on when windows starts/resumes and go off when you shutdown/hibernate/standby so the amp is on only when it's of any use, or by software in any other way really. But then this would only save you a few seconds of power compared to what you already have.

  4. #14
    Low Bitrate nrls2000's Avatar
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    Quote Originally Posted by Curiosity
    If done through the serial port (or LPT or whatever), it can go on when windows starts/resumes and go off when you shutdown/hibernate/standby so the amp is on only when it's of any use, or by software in any other way really. But then this would only save you a few seconds of power compared to what you already have.
    I have tried similar timing sequences, and it does not work like I want it to. The amplifiers will have turn on pop and static until audio signal is present and then the amplifiers will turn off after audio signal is gone giving a loud thud.
    Unacceptable for my application

    My timer relay circuit eliminates the static, pop and thud as long as the computer remains within standby and hibernate time parameters.

    I am satisfied with this until I can find an accepable circuit that will be triggered by audio signal.

  5. #15
    What can I say? I like serial. Curiosity's Avatar
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    Well, if it ain't broke, don't fix it. The only other problem I have is that the LCD would stay on in standby. Do you power that the same way as the amplifier?

  6. #16
    Raw Wave rando's Avatar
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    If done via software, you can have it turn-on/shut-off any way you want. You'd probably need to integrate it with your audio software if you truly want it to turn on ONLY after the audio stream is playing and just before the audio stream ends. Usually, the source of the thump is your computer audio hardware getting energized/de-engergized. In that case, as long as it comes on after the computer and goes off before the computer, you should be ok.

    I don't use the software on/off for my amp. Mine is wired to turn on only if both the ACC line and the PSU +12V rail are on. Since the amp has brief turn-on delay built-in, the sound hardware always gets energized just before the amp comes on. When turn the car off, the amp goes off immediately ... long before the computer ever shuts down. This solution is thump free.

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