Long Duration Timer Setup 4060

Discussion in 'The Projects Forum' started by jj_alukkas, Mar 22, 2012.

  1. jj_alukkas

    Thread Starter Well-Known Member

    Jan 8, 2009
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    Hello,

    I need to build a long duration astable timer which can run a motor at an interval of 4hrs off 20mts on repeatedly. I started of with this circuit and bread boarded the two stages separately.
    [​IMG]
    The whole article can be found here. On providing a high to 4001, it runs for a couple of minutes and pulls output low as it should, just need to adjust the duration. However the first stage seems to have some problem. The two diodes marked at the bottom of 4060 are LED's I guess from the description and I connected as so. One led blinks every 4-5 seconds for some 300-500ms each and the other goes on for 4 secs and off for 4 secs, adjusting the preset brings a few seconds +/- only to this. According to the article, I should be looking at at the led blink cycling at 28 secs, however I cant get it to go beyond 10 sec. On wiring the whole setup of two stages together with pin 1 of 4060 selected for test, the relay goes high after a minute or 2 from power on instead of going after couple of hrs. The datasheet for 4060 didn't do me any help, could somebody help me figure this out please?
     
  2. jj_alukkas

    Thread Starter Well-Known Member

    Jan 8, 2009
    751
    5
    Does anyone know a long duration timer with 4060 other than the one posted above? Please help
     
  3. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    We shoul be able to come up with a timer. One question- does the first cycle start with relay off or can we start with the 20 minute on then 4 hr off??
     
  4. #12

    Expert

    Nov 30, 2010
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    First math: If osc = 7.03125 seconds,
    Pin 3 = 4.0 hours
    Pin 15 = 15 minutes
    pin 1 = 30 minutes.

    The problem here is that 20 minutes is 1/12 of 4 hours, and 12 has a 3 in its factors but divide by 2 circuits don't have any 3's.

    Can you choose 15 minutes or 30 minutes? or a long interval that is the short interval multiplied by some number of 2's?
     
  5. Wendy

    Moderator

    Mar 24, 2008
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    I have designed several using (what else?) a 555 / 4060 and diode gate. You want links?
     
  6. jj_alukkas

    Thread Starter Well-Known Member

    Jan 8, 2009
    751
    5
    Either way its fine, its an irrigation pump timer which runs 24x7, so all is good.
     
  7. jj_alukkas

    Thread Starter Well-Known Member

    Jan 8, 2009
    751
    5
    But its not the second stage that is the problem, first stage where I need long duration timing gives problems. So how is that 15 and 30 minute related to it?
     
  8. jj_alukkas

    Thread Starter Well-Known Member

    Jan 8, 2009
    751
    5
    Yes sure please, It is the 4060 that gives me the problem and if you can help me with it using 555 as well, would be great! Also sorry to say, it would be so kind if the circuit does not have a CMOS 555 as I cannot get it here. Thanks a lot!
     
  9. #12

    Expert

    Nov 30, 2010
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    Referring to post#7

    I was thinking to eliminate the big capacitor and do all the timing with the 4060 chip.
     
  10. jj_alukkas

    Thread Starter Well-Known Member

    Jan 8, 2009
    751
    5
    No problem, give me a suggesion and ill try.
     
  11. #12

    Expert

    Nov 30, 2010
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    I gave you the suggestion in post #4.
    If you can choose the timing periods so that the larger time is some number of 2's times the shorter time, the 4060 can be used to do all the timing.
     
  12. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Here is my version: If the relay operates at 12V & under 200mA, then the 555 can drive it. The clock period is .879 sec if using Q14 ; it goes high at 2 hours, & falls at 4 hrs. Diodes might be 1N400X X=2-7. Seems that diode across relay is reversed.
     
    Last edited: Mar 23, 2012
    jj_alukkas and #12 like this.
  13. #12

    Expert

    Nov 30, 2010
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    Bernard, are you using the 555 to make the 20 minute time period?
    I don't see enough capacitance to do that.
     
    Last edited: Mar 23, 2012
  14. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Sometimes I don't know the difference between minutes & seconds. A more realistic value might be 1500 μF. It still makes me nervous to dump large caps via pin 7, so I usually stick in some resistance between between pin 6 &7 Some day I'm going to monitor discharge current to see if there is some limiting in place.
     
  15. #12

    Expert

    Nov 30, 2010
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    True. The spec sheets don't show any limiting on the dump transistor current. It's scary to consider dozens of amps trying to get through it!

    If 1.1RC = time in seconds, the answer is 1080uf (including the 10k resistor).
     
  16. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    True, but my junk box did not have a 1080μF cap. That's why I like pots, they cover up a lot of sloppy math & +- 20% tolerances.
     
  17. jj_alukkas

    Thread Starter Well-Known Member

    Jan 8, 2009
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    @Bernard
    Thanks a lot for this schematic! Let me try the 4060 part first, this circuit is for 2hr on+2hr off=4 hr cycle? I need to run the pump every 4 hrs, so will this suffice? Thank you again!

    @#12
    Thanks for the suggesions, will rewire everything and try again to check if my old breadboard has problems.
     
  18. Wendy

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    Mar 24, 2008
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  19. Bernard

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    Output to 555 is every 4 hr.
     
    jj_alukkas likes this.
  20. jj_alukkas

    Thread Starter Well-Known Member

    Jan 8, 2009
    751
    5
    So after all the guidelines by the senior members here, I modified the first circuit to this. Everything runs fine, except there is some trouble.
    [​IMG]

    When I switch the circuit on, the output from 4060 is low, but due to the power on, the relay goes on, timing starts and 20 mts later relay goes off, stilll 4060 output is low, this is not a problem. Then exactly 3hrs later from power on, the relay goes on again as output from 4060 is high. 20 mts later, the relay starts tapping badly, like rattling. rattles for 1 sec, off for 1 sec, then rattles again for 1 sec and so on. The ouput from 4060 is still high.

    From what I observed, the 4060 has a 1.5hrs on and 1.5hrs off. so when the 4001 has timed out for 20 mts and if still the 4060 is giving a high, this wierd activity happens. WHat should I do?
     
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