delayed on/off relay?

Discussion in 'The Projects Forum' started by halcyon026, Feb 4, 2014.

  1. halcyon026

    Thread Starter New Member

    Feb 4, 2014
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    Great forum!

    I've been trying to figure out exactly what I need but I don't understand the lingo so I'm confused. I'll explain what I'm wanting.

    I have a switch that switches a ground on/off which then grounds the unit so the 12v power lead turns on the unit. It has 2 leads coming off the switch which are basically both grounds. One lead you actually ground, the other end is what switches to the other lead to complete the grounding circuit. That grounding lead is connected to a 12v unit that has a 12v lead and a ground lead (this ground is what is connected to the switch).

    Here's where the delay relay comes in. In my application the switching (on/off events) can happen frequently from vibrations. I'd like to delay the on/off events so that the switching only happens if an ON event is consistently being made for X amount of seconds and for it to switch off only when an OFF event is consistently being made for X amount of seconds.


    I hope that makes sense...

    I don't need this to be an expensive high quality thing by any means. And the smaller the better.

    Something small & cheap like these would be fine:
    http://www.amazon.com/PowerArt-Switch-Adjustable-Module-Electrical/dp/B00CRYUSR2
    http://www.amazon.com/Power-OFF-Delay-Relay-Module-Circuit/dp/B00EZJMADC/

    But I'm not sure if those units function how I need.

    Thanks a lot guys!!
     
    Last edited: Feb 4, 2014
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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  3. inwo

    Well-Known Member

    Nov 7, 2013
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    Assuming that this is not automotive, and about 12vdc from unknown sensor.

    Connect about 3300uf in place of the led.
    Then connect led to the Capacitor thru about 470ohms.

    edit:

    Oops, where did the led reference go?
    I must be dreaming!
     
  4. halcyon026

    Thread Starter New Member

    Feb 4, 2014
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    I thought I wasn't allowed to post about LEDs? I posted a new drawing. Can I post about LEDs? :)

    So with your recommended setup, what would take place? Would this delay the ON/OFF events? By how long?
     
  5. inwo

    Well-Known Member

    Nov 7, 2013
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    Leds are fine. If this is an automotive mod, it's not allowed.

    There will be better solutions than what I suggested.

    It's quick and dirty fix.

    I'm making a lot of assumptions.
    One is that there is a current limiting resistor in the tank.
    Two is that it's a switch. (led is on or off)

    Rather than turning the led on, the switch will charge the capacitor. (integration)


    The capacitor will "remember" if the switch has been on lately.
    It will also keep the led on for a few mS after switch opens.

    Time is based on values of resistor and capacitor and resistor in the tank. If any.

    edit:
    This will only work with led, very tiny relay, or meter movement.
    If it is led, see if you can find the resistor.
    If I know where that is, I can make a drawing.
     
  6. halcyon026

    Thread Starter New Member

    Feb 4, 2014
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    Are there any products you can link me to that do what I'm looking for? Like the ones I linked to...

    The drawing shows the current setup. The LED does have a resistor in place now. Not sure what rating, it came that way.

    1. This is for an LED
    2. The switch just completes the circuit for the ground wire. I don't believe there is a current limiting resistor here.
     
  7. inwo

    Well-Known Member

    Nov 7, 2013
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    I really think this will do what you want without the complexity of timers.

    I'll draw it up.

    Now that we know there is an external resistor, it can be easily simulated.
     
  8. inwo

    Well-Known Member

    Nov 7, 2013
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    This can easily give a couple seconds.
    Adding a transistor will do much more.
    Start with existing resistor and 1 to 3 thousand uf.
     
  9. halcyon026

    Thread Starter New Member

    Feb 4, 2014
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    Ok! I was keen to the timers, like the ones I linked to because of the idea of being able to adjust the time. Without having to rewire things. I'm not exactly sure what amount of time I'll want to delay the On/Off events just yet.

    Thank you very much for your efforts on helping me!
     
  10. halcyon026

    Thread Starter New Member

    Feb 4, 2014
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    Well, I hate to say it but I know nothing of the world of circuits so your drawing means nothing to me. LOL! :)

    Another reason I was hoping for an already made product. So it's more idiot proof for a newbie like me.
     
  11. inwo

    Well-Known Member

    Nov 7, 2013
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    I'd try this first. (kiss)

    Do you want an off the shelf timer or build your own?

    If you want to build, a search here should come up with delay on/off timers.
     
  12. inwo

    Well-Known Member

    Nov 7, 2013
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    The delay off timer you linked should work.
    Seems it would be more complicated to implement.

    This is the only part to buy.

    http://www.ebay.com/itm/2pcs-3300uF...351?pt=LH_DefaultDomain_0&hash=item3a797fcb07

    It has a plus and minus.

    Connect it where your light is now. From +12 to tank switch.

    Then the led with the resistor still connected to it is connected to the capacitor.

    If you don't understand, I get it!:D Seems no one understands my explanations.

    That's why I'm not alone here.
    Someone will jump in and help us out. (or correct me):p
     
  13. TANDBERGEREN

    Member

    Jan 20, 2014
    74
    4
    What you really are looking for is a debouncer for your switch.

    Actually You could use a simple courtesy light delay switch, something like this: http://www.ebay.com/itm/TIMER-SWITCH-10A-Delay-Off-Switch-12V-TIME-RELAY-FROM-1-TO-40-SEC-KIT-ON-Button-/220957321530

    Will set you back a whopping $7,- but I think it will do the trick.
     
  14. inwo

    Well-Known Member

    Nov 7, 2013
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    That should work fine.

    Here's a picture if diagram is confusing.
     
  15. halcyon026

    Thread Starter New Member

    Feb 4, 2014
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    You guys are awesome!!! I'll get into your posts further to see if I got this figured out. But one question comes to mind.

    If it's a Delay OFF timer I'm wanting, won't the LED still be quick to flash on and just delayed in turning off?
     
  16. inwo

    Well-Known Member

    Nov 7, 2013
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    Yes and no.

    Yes it will be quick coming on. But it won't flash on. It will stay on for the set time (say 2sec).

    It will be retriggerable. Meaning it will stay on until it doesn't get bumped for xx seconds.

    I'll look for a TD on and off.

    The capacitor method won't blink on an off but will dim while fuel is sloshing.
     
  17. inwo

    Well-Known Member

    Nov 7, 2013
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    On another thought.

    If you get the "delay off" from your link or the one suggested by TANDBERGEREN, we should be able to modify for delayed triggering.
    Giving on and off delays.

    Seems much to complicated for a fuel indicator.
     
  18. halcyon026

    Thread Starter New Member

    Feb 4, 2014
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    Ha! Yeah. well I was hoping there was an on/off delay device already made that would work...

    That way it's simple for others to link me to it and I just have to connect the wires. No reconfiguring or modifying something else and people having to explain to a newbie how to do it. :)

    Any luck finding an on/off delay?
     
  19. inwo

    Well-Known Member

    Nov 7, 2013
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    No luck, under $100.:eek:

    You could use two. One delay on and one delay off.

    I have a thermo type fan control. 30sec on - 30sec off but it's 24 volt.
    Tried it and it doesn't work on 12vdc.

    If it was my project, I might try modifying it.

    Maybe you could talk someone on here into building a kit for you.
     
  20. inwo

    Well-Known Member

    Nov 7, 2013
    2,433
    315
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