timer with more than 2 or 3 days delay

Discussion in 'General Electronics Chat' started by vahidasadi, Aug 15, 2012.

  1. vahidasadi

    Thread Starter New Member

    May 21, 2010
    11
    0
    hi
    it's strange that i couldn't find my answer
    i want to build the most simple circuit so that i connect it to a water pump
    i want to pump the water every 2 or 3 or 4 days for 20 min automatically using a timer and a relay connected to water pump
    it's impossible to use only 555 or even 4060. i read a lot but i got confused
    what is decade counter like 4017? is it possible to use it for my project
    i don't want an exact timer, + , -1 hour or 2 hour is not matter
     
  2. t06afre

    AAC Fanatic!

    May 11, 2009
    5,939
    1,222
    The simplest circuit would be a micro-controller circuit. Is this out of the question? For such long intervals the 555 timer is not suited very well. I think the cheapest thing will be some of the shelf timer
     
  3. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,771
    971
    I just bought an off-the-shelf watering timer at lowes. It does exactly what you want and way more. It was under $50 USD. Does 4 zones,etc..

    But yes a microprocessor (maybe a real time clock chip too) is the best way to accomplish this yourself.
     
  4. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,176
    397
    A commersial timer that does what you want may be best, but a 4060, 4017, AND gate , & relay driver should work. Seconds in a day = 86400, divided by max count of 4060, 8192 ?, gives a clock of 10.54 sec Use 4017 [4022], to count days. Gate day selected with 128 count of 4060, to control relay; at trailing edge of 22 minute , reset all & start over. Or just use day counter & a 555 for watering time.
     
    mkbutan and #12 like this.
  5. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,395
    1,607
    Another interesting chip for long timeouts is the CD4536. It has an RC oscillator (you make the RC) followed by several dividers and a binary input controlled divider that can divide by 2^1 to 2^24
     
  6. vahidasadi

    Thread Starter New Member

    May 21, 2010
    11
    0
    i hope you could explain it more in details, i'm not so much experienced .
    you mean i need both 4060 and 4017?
     
  7. Mr. Mho

    Member

    Jun 15, 2009
    15
    3
    There's a programmable 555 that includes a 6 decade counter that you can use to make a 2 to 4 day timer very easily. It's the CSS555 - I think Jameco carries it. The manufacturer (CSS) provides a "Timing Calculator" to help you select the appropriate components. I just checked to see if you can get what you want, using the "Adjustable Duty Cycle - Circuit #2" circuit - you can. If:
    RA = 5Meg
    RB = 5K
    RF = 5K
    CT = 0.22uF
    Counter = 1,000,000

    Delay = 108 hours
    PW (ON time) = 0.36 hours

    A schematic of the circuit is shown in the calculator.

    This is similar to the previous approach (OSC + Counter), but only uses one 8 pin part and lets you set the duty rate with resistors.
     
    absf and #12 like this.
  8. crutschow

    Expert

    Mar 14, 2008
    13,056
    3,245
    The CSS555 looks like it would work fine for the long time period, but you would need two -- one for the long delay and one for the 20 minute ON time.

    As others have mentioned, I would just buy a cheap lawn watering timer. It's a lot easier and probably won't cost that much more after you buy all the parts (power supply, circuit board, chassis box, etc.).
     
    Bernard likes this.
  9. #12

    Expert

    Nov 30, 2010
    16,348
    6,836
    Here are some datasheets about the CSS555C timer. It requires a USB connection to a computer and a demo board to set it up. (Not the kind of fun I like for my hobby.)
     
    absf and gerty like this.
  10. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,176
    397
    After reviewing all comments & you still wish the 4060 route, we will try to oblidge. What is your electronic assembly, schematic reading experience, & parts availability ??
     
    absf likes this.
  11. vahidasadi

    Thread Starter New Member

    May 21, 2010
    11
    0
    well i'm not sure about css555 method ,especially that it needs developing kit because i'm living in Iran with low resources. I haven't tried to find commercial one but i will search locally , i'm interested in DIY projects and i do have experience building DIY boards and sure i can find the regular parts
     
  12. t06afre

    AAC Fanatic!

    May 11, 2009
    5,939
    1,222
    Of course you must design with what you have at hands. The task of yours can be done with discrete logic. I will be off line next week, so I can not help. But others will for sure pitch in. Good luck
     
  13. absf

    Senior Member

    Dec 29, 2010
    1,493
    373
    Bernard is willing to help if you tell him whether the chips like 4060, 4020, 4040 or 4017 and common NAND and NOR gates are available in your place. I myself is also interested to see how to design a 3 days delay without using a mcu or a sophisticated 555.

    Allen
     
  14. vahidasadi

    Thread Starter New Member

    May 21, 2010
    11
    0
    It's very nice of all of you, thanx
    here it's two day holiday and i don't have access to local stores, i will inform you ASAP after holidays
     
  15. Mr. Mho

    Member

    Jun 15, 2009
    15
    3
    Just a couple of corrections re the CSS555:

    You only need one. I've attached a PDF of the "Timing Calculator" for the configuration I suggested. You can download the spreadsheet version from CSS's website. The delay can be adjusted with RA, I picked the longest delay you mentioned - 4 days (96 hours). The ON time is set by RA & RF... I've sete it for .31 hours (18.6 minutes)

    This part has an internal programmable decade counter. There are two programmers available for it, one attaches to a PC via a USB, the other (simpler) uses DIP switches and does not require a PC. Once the part is programmed, the configuration info is stored in an EEPROM, much like a PLD. It does NOT need to be connected to the programmer to operate in your timer, just like a PLD.

    The CSS555 offers a very simple circuit, an 8 pin IC plus 5 small, passive devices. The down side is you need to program it. It's default configuration is a "normal" 555 - for your application, you need the 1E6 counter to get a 4 day delay, and it needs to be re-programmed for that.
     
    #12 likes this.
  16. vahidasadi

    Thread Starter New Member

    May 21, 2010
    11
    0
    sorry for delayed reply, we had an earth-quick here :eek::eek::eek:
    i searched local stores, all of @absf mentioned chips are available (4060, 4020, 4040 or 4017) but not CSS555 named thing :confused:
    i actually found pre-built electro-mechanical timer costs about 40$ but i want to do it myself and that's this community's goal right?
     
  17. #12

    Expert

    Nov 30, 2010
    16,348
    6,836
    The CD4020 is a 14 stage binary counter which means 16,384 counts, I think.
    The CD4017 is a 5 stage decade counter (with 10 decoded outputs)and I can't figure out how high it counts.
    Both use very low current and have their own oscillators.
     
  18. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,176
    397
    Here is one version: There still maybe some glitches in ckt, but it is a start. Forgot a start-up reset for U3. D3 is reversed & needs another change. R1 + R2 = 1 M, R3 about 3M to 10M, R2 easier to adjust if multi turn trim pot. Cx would like to be 15μF , non polorized, but might have to settle for series combination of polar caps. Tolerances vary greatly. U1 clock period = 10.546875 sec, so after 8192 counts we have 86400 sec or 1 day. 2P-4T SW, or jumpers on plug strip, selects no of days. 20 min timing cap C4 might be 1000 μ F with tolarance to high side, or increase R6 to get 20 min, should be low leakage. I'll be out of touch for a few days, but keep your questions coming. Q9, pin 13, should give 45 min when it resets lo if timing is proper for one day, or pin 6 = 11 m 14 sec.
     
    Last edited: Aug 27, 2012
    absf likes this.
  19. dataman19

    Member

    Dec 26, 2009
    136
    29
    What Bernard and EarnieM originally said....
    ..
    The basis of almost all non electromechanical lawn sprinkler timers...
    ..
    By the way I have three of these electromechanical timer beasts - they are over 20-years old, and use a set of pins (one pin for on, one pin for off) that can be positioned in any number of groups (pairs) to make over twelve sprinkler solenoids go on and off at varying intervals throughout the day. then there is another wheel with seven slots for days of the week (so you can activate the wheels for the hours/ 1/4 hrs of the days any day or group of days of the week.
    ..
    Really handy little critters.... and oh so simple. So simple that landscapers have a hard time understanding that for every on pin, there must be an off pin (otherwise once it goes on - it will stay on and the water will run down the street until an off pin is encountered. Leave the off pin out and the water will run and run and run.... forever). Simple concept, but too simple for some simpletons...
    ...
    Dave
    Phoenix, AZ
     
  20. vahidasadi

    Thread Starter New Member

    May 21, 2010
    11
    0
    @Bernard : is U1 unit just to supply U2 unit's clock supply?
    why not using simple crystal? and could you plz tell me every unit's duty?
     
Loading...