need help please

Discussion in 'General Electronics Chat' started by snn77, Oct 9, 2013.

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  1. snn77

    Thread Starter New Member

    Oct 9, 2013
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    :) Hello everyone,

    I need a circuit to control a relay so that when I trigger the cercuit for only one time the relay should not connect, but if I trigger again withen 5 seconds then it should activate the relay. even if it activate the relay for a 1 second its enough for me. any help from you guys would be much appreciated :)

    Regards
     
  2. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    how is the relay deactivated? after a certain delay? or manually?
     
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  3. snn77

    Thread Starter New Member

    Oct 9, 2013
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    thanks for your reply,

    I need it to disconnect after one second, even milliseconds enough for me.
     
  4. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    I'll draw something up later. It's just two 555 monostables, an OR gate and the relay.
     
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  5. MrChips

    Moderator

    Oct 2, 2009
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    I will be Title Cop for the day.

    Please use a title that is more descriptive.

    Imagine how useful it would be if everyone posted "need help please".

    Think about helping your readers by providing proper information in the title in the first place.
     
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  6. praondevou

    AAC Fanatic!

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    [​IMG]

    On power-up both timers are off. Once the switch is pushed, the upper timer will trigger, the lower timer remains off because at that time its RESET input is LOW. Next time the push button closes the lower 555 will trigger, turning on the relay. This will only happen as long as the upper 555 is ON. Once the lower 555 is triggered the upper can turn off, the lower 555 will finish its timing sequence.

    If switch bouncing is a problem it might be necessary to modify the circuit around the switch, e.g. it shall not bounce after the output of the upper timer is ON...

    The OR can be any OR gate not necessarily the LS version. Can be done with two diodes and a resistor as well.
    The 555s also need bypass caps.
     
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  7. snn77

    Thread Starter New Member

    Oct 9, 2013
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    Hi,

    Thanks alot for your quick reply, the diagram is very clear and very good, just i have few questions. by the way i dont have good idea about electronic schemas but i can do soldering and follow the schemas very well.
    My questions are :
    1. Is S1 the trigger switch?, and is K1 is the coil of the relay?
    2. Is VCC means the positive source of the current?
    3. Does this works on 12 volts? because i will goig to use it in my vhicle which have 12 volts only.
    4. I didnt know what is 74LS32D, clould you please attach a picture of it? and also you mantiuned that if i dont have the 74LS32D then i can use 2 diodes and one resistor to do it, could you please clerify what is the specs of the diodes and appriciate if you could provide me with another diagram on how to connect the diodes and the resistor to get the OR Gate.

    thank you very moch for your help
     
  8. shteii01

    AAC Fanatic!

    Feb 19, 2010
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  9. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    1. yes
    2. yes, 12V for example, you can use the same voltage for the relay to keep things simple
    3. oops, did you just say vehicle? See ToS please. You don't mean an on-road vehicle , right?
    4. first tell us what you want to do with this circuit.
     
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  10. snn77

    Thread Starter New Member

    Oct 9, 2013
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    Hi,

    thanks a lot for your prompt reply, appreciated.

    well I am going to use this circuit in my car but of Corse after testing and making sure its working properly, in my car I have a central lock system which locks the doors when I press the lock button on the remote. I have installed a windows roll up module so whenever I lock the doors from the remote control the module will roll up any open window, of Corse this module has a current sensor that senses the load on the motor when the window closes completely which disconnects the relay that providing power to that window and switch's to the next window and so on till it closed all windows. but because the weather is cold these days so I am not rolling down any window, so when I leave my car and lock the doors the module is forcing window motors for 1 second in every door, which I don't want that because it will damage the motors later. that's why I am thinking of making this circuit and use it behind the module so if I press my car remote lock button once it just lock the doors and if I press it once again in less than 2 seconds then the circuit will trigger window module then it starts rolling up the windows, honestly I will just use this module in my car I am not making business of this.

    once again thank you very much for your help
     
  11. praondevou

    AAC Fanatic!

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    The owners of this site decided against allowing discussions on ANY automotive modifications.
     
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  12. snn77

    Thread Starter New Member

    Oct 9, 2013
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    apologies to the site owners, I wasn't knowing that automotive topics were restricted the time I opened the thread, I am sorry, admin please delete my thread.
     
  13. Wendy

    Moderator

    Mar 24, 2008
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    The owners of All About Circuits has elected not to host discussions of automotive electrical system modifications/enhancements due to safety concerns, the potential of legal ramifications and the possible circumvention of vehicle regulations at the state and federal level.

    This thread is against the AAC forum rules, Chapter 6, as seen here:

    This can be found in our Terms of Service (ToS)

    Automotive modifications of any kind are strictly forbidden. Therefore, this thread will be closed.

    Please try to understand the reasons behind this action, and feel free to browse and use the forums.

    You might find answers to your questions in one of these forums:

    http://forum.allaboutcircuits.com/showthread.php?t=54400

    Another good forum that shares many of the same membership is http://www.electro-tech-online.com/ . Good luck.
     
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