short/open contact switch controlled by AC power on/off

Discussion in 'The Projects Forum' started by freshcoffee, Apr 25, 2015.

  1. freshcoffee

    Thread Starter New Member

    Mar 24, 2015
    21
    0
    Hello,

    is there an ON/OFF or Short/Open momentary switch working by AC power? which means short/open is controlled by AC on/off.

    i am testing a simple LED sync with music circuit
    and its powered by 9V DC adapter, and i plug the adapter in the power strip.
    a problem that i have now is .. when i turn off the power, LED is still blinking by remained power in adapter.
    so, i am trying to figure out the way to cut the actual power flow between the circuit and power adapter in order to make LED stop blinking immediately when power strip is turned off.

    what i am thinking is.. i keep feeding the circuit with 9V, and just cut the current flow (or whatever proper term) with something that i am looking for above.

    does it make a sense to you?

    is there such thing off the shelf or should i create one?

    thanks in advance.
     
  2. #12

    Expert

    Nov 30, 2010
    16,343
    6,828
    Put a switch in the circuit between the LEDs and the power adapter.
     
  3. freshcoffee

    Thread Starter New Member

    Mar 24, 2015
    21
    0
    thanks for the reply,

    i think i forgot to mention this...
    i have to use the power strip to switch things, because the power strip is Z-Wave capable and i am trying to switch the LED on/off with the power strip with remote control.

    therefore,
    the switch you suggested need to be plugged in the power strip so that i can control it wirelessly
    is there these kind of switch?
     
  4. #12

    Expert

    Nov 30, 2010
    16,343
    6,828
    Use a relay that operates on whatever voltage you have in whatever country you are in and arrange its contacts to stop the power that comes out of the 9 volt adapter.
     
  5. freshcoffee

    Thread Starter New Member

    Mar 24, 2015
    21
    0
    thanks for following up,
    i am in usa. do you have any suggested product that i could use? from amazon or mouser... or wherever..

    thanks
     
  6. #12

    Expert

    Nov 30, 2010
    16,343
    6,828
  7. freshcoffee

    Thread Starter New Member

    Mar 24, 2015
    21
    0
    thank you very much
    i can do more test with your suggestion.
     
  8. #12

    Expert

    Nov 30, 2010
    16,343
    6,828
  9. freshcoffee

    Thread Starter New Member

    Mar 24, 2015
    21
    0
    i think it's better for me to to use 120VAC, because i have 7 set of the LED circuit and want to use controllable power strip with 7 ports.
    so i would like to use just one 9V DC (or appropriate voltage) to feed the circuits and use the relays to shut on/off the power to the circuits with power strip.

    does it make a sense to you?
     
  10. #12

    Expert

    Nov 30, 2010
    16,343
    6,828
    I think you should do the wiring on the 9 volt side of the adapter. Less chance of getting hurt.
     
  11. freshcoffee

    Thread Starter New Member

    Mar 24, 2015
    21
    0
    i am watching some youtube video to learn how it works, and kind of getting idea.

    yes i was going to ask about the safety,
    according to your suggestion, i guess i have to use 7 separate 9vdc adapter with 7 relays in the middle of circuits,
    am i understanding correctly?
     
  12. #12

    Expert

    Nov 30, 2010
    16,343
    6,828
    No. There is no rule that says a 9 volt adapter can only run one relay.
     
  13. lmarklar

    New Member

    Apr 23, 2015
    24
    3
    Why would you need 7 relays? Wire the relay to provide power to your entire circuit. When you turn off AC power then the entire circuit is off. When you apply AC power the relay turns your circuit on and your timers do their thing, then you only need one relay.

    Maybe I'm misunderstanding what you are asking.
     
  14. freshcoffee

    Thread Starter New Member

    Mar 24, 2015
    21
    0
    there was reply button... i just learned. :)
    probably i confused you and i didn't understand correctly.

    as i mentioned, i have 7 circuits, and need to turn on/off them "independently."
    so i guess..
    i need 7 relays for 7 circuits. and those relay will be in the middle of each circuit.
    seven 9VDC adapter feed the 7 circuits and 7 adapter plug in the power strip that i can control on/off wirelessly.

    i hope that this is more clear
     
  15. lmarklar

    New Member

    Apr 23, 2015
    24
    3
    So.... you are turning off each 9v adapter individually, are the circuits located close to each other or are they separated by a large enough distance that they require individual adapters?
     
  16. freshcoffee

    Thread Starter New Member

    Mar 24, 2015
    21
    0
    it's together.
    i don't want to use many adapters if i can avoid it.
    just turning on/off adapter is simple to me, but i have to cut the power flow from the turned off adapter, that's the problem.
     
  17. lmarklar

    New Member

    Apr 23, 2015
    24
    3
    Why not use a single 9v adapter for the entire system and a separate wireless DC switching option then?

    http://www.rfcontrolsystem.com/index.php?main_page=product_info&products_id=206

    Probably not the best, it's just the first one I saw when I googled 8 channel wireless DC switch. But I think it would work for your application. No relays wired individually, only one power adapter. Much much cheaper.
     
  18. freshcoffee

    Thread Starter New Member

    Mar 24, 2015
    21
    0
    thanks for the suggestion.
    i think it's a good product by itself.
    however, i am using certain networked remote control which uses TCP/IP, and Z-wave. that means RF doesn't work for me.
    i can control the power strips on/off with remote control
    i wish i could use the product linked.

    Best,
     
  19. lmarklar

    New Member

    Apr 23, 2015
    24
    3
    Looks like you're stuck with the expensive option unless you find a way to dump the residual voltage. Without a full description of the project and a schematic, stick with #12's advice then. Although you might be able to put a bleed off resistor in the circuit to drain it when the power is removed. Not sure how fast you need to switch it off, or if you can accept the voltage drop by leaving a resistor to ground when powered up. Plus a high enough resistance to be safe and not get super hot would probably take 5~10 seconds to bleed depending on the charge size.
     
Loading...