help with 555 timer

Discussion in 'The Projects Forum' started by starrz, Jan 6, 2013.

  1. starrz

    Thread Starter New Member

    Jan 6, 2013
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    good day everyone, I am trying to build a circuit that can turn a relay on , off, then on again maybe in a 2 seconds interval and remain in that state until powered off and repeats this same cycle every time its powered on. I am familiar with 555 timer ic and 4017 ic which was the initial circuit i was trying to modify to achieve this effect however it cycles continuously where just one cycle is desired. It also doesnt have the power output to drive a 12v relay. Could anyone guide me in the correct direction , your help will be greatly appreciated
     
    Last edited: Jan 6, 2013
  2. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    I can see how it can be done with three 555s, but there may be a simpler way, and someone will disclose it.
     
  3. starrz

    Thread Starter New Member

    Jan 6, 2013
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    any suggestions would be greatly appreciated, i also have some 556s if you all think it can be utilized
     
  4. Wendy

    Moderator

    Mar 24, 2008
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    I've actually designed this. Got to go to work, but you can browse my blog for ideas until I have more time.

    Bill's Blog
     
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  5. starrz

    Thread Starter New Member

    Jan 6, 2013
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    my there is a lot of blogs on page , is there a name for this type of circuit and could you narrow give me a little more insight on what i should try and search for thanks
     
  6. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    Is this the sequence you want?

    Initial condition: Power is off and relay is not operated.
    1. Power is turned on by external force.
    2. Relay operates.
    3. Pause 2 seconds.
    4. Relay releases.
    5. Pause 2 seconds.
    6. Relay operates.
    7. Pause until power is turned off.
    8. Power is turned off by external force.
    9. Relay releases.
    Back to initial condition.

    It can be done easily with a microcontroller. Are you interested in that or do you prefer an analog solution?
     
  7. starrz

    Thread Starter New Member

    Jan 6, 2013
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    its exactly what am looking for, all longs as parts can easily be sourced am up for the microcontroller, please elaborate i have been struggling with this for a while using 555s
     
  8. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    Here is a link to a kit which contains everything you will need for the circuit except the microcontroller and the relay.

    http://www.picaxe.com/docs/axe021.pdf

    Here is a US source for the kit and the microcontroller (08-M2).

    http://www.phanderson.com/picaxe/picaxe_rev_ed.html

    Here is a link for more information and the free software to program the microcontroller.

    http://www.picaxe.com/

    You will also need a programming cable, either USB (which is about $22) or serial (if you have a serial port on your computer) and is much cheaper and can be home built.

    There is a learning curve, but it's not steep. Have a look at the links and see what you think.
     
  9. starrz

    Thread Starter New Member

    Jan 6, 2013
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    great suggestion but may i ask what would the analog solution look like, sourcing of parts is a main factor her being whatever my local shop can provide, my best bet is that they most likely have the parts for the analog approach available.
     
  10. tracecom

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    Apr 16, 2010
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    Where is "here," i.e., where are you?
     
  11. starrz

    Thread Starter New Member

    Jan 6, 2013
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    trinidad to exact, we have radio shack but they cant come near what radioshack offers in the U.S. They dont have any of the popular parts available and other local spare parts shop stock alot more but focus mainly on parts needed for appliance repairs with a few 555s and 4017s just as a bonus
     
  12. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    Here's what I think will work. It's not very elegant, but it makes use of the parts you have, plus a few.

    Build a 555 astable with a 1 second on/1 second off output. Connect that to the clock input on the 4017. Connect a non-inverting relay driver circuit to the number 0 output on the 4017. Connect a transistor latch circuit (which will also serve as a non-inverting driver circuit) to the number 2 output. Use two diodes to OR the two driver outputs together, and connect the OR output to the relay (using a protection diode across the coil.)

    A non-inverting transistor latch circuit is attached. You can use an identical circuit, but without R3, for the non-inverting relay driver.
     
    Last edited: Jan 7, 2013
  13. starrz

    Thread Starter New Member

    Jan 6, 2013
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    so with this latching circuit its gonna run on , off, then on and latch right there?
     
  14. tracecom

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    My thinking is that when power is applied, the 555 willl start clocking the 4017. When output 0 of the 4017 goes high, the relay will operate for 2 seconds; then the 555 will go low/high, the 4017 output 0 will go low, output 1 will go high, and the relay will release for 2 seconds. The third time the 555 output goes high, the 4017 output 2 will go high, and the connected transistor circuit will go high and latch. During this time, the 555 and the 4017 will continue to run, but they have no effect because the transistor latch is latched and holding the relay operated. Only when power is cut does the entire circuit power down and the relay releases. Then, the cycle is ready to start again.
     
    Last edited: Jan 7, 2013
  15. tracecom

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    Apr 16, 2010
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    I have done some experimenting with the 4017, and, while I still think my previous suggestion will work, there may be an easier way. I'll post more when I know more.

    How will power be turned on and off?
     
  16. ScottWang

    Moderator

    Aug 23, 2012
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    If the condition as tracecom listed, then maybe you can use NE555 and CD4017 and some 1N4148 diodes Bjt circuit and relay to do the Job.
    NE555 2 Seconds → CD4017 → 1N4148 → R → NPN Bjt → Relay
     
  17. starrz

    Thread Starter New Member

    Jan 6, 2013
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    another 12v circuit with a IR remote is feeding this one
     
  18. tracecom

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    I am watching the BCS game, but I will post a simplified solution later tonight or tomorrow.
     
  19. tracecom

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    I want to recheck this, but it should be close. Maybe ScottWang or somebody could verify it?
     
  20. starrz

    Thread Starter New Member

    Jan 6, 2013
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    i actually have the 555 and 4017 connected in a breadboard using a 9v battery just for testing purposes at the moment. whenever i connect that output 2 to clock disable output 0 just remains on and is stuck right there no other leds light up. i actually have alot of 3904s in hand
     
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