Timers

This would be an excellent use of a PIC microcontroller (16F690, 18Fxxx); requires some knowledge of programminf/assembly language, though Microchip.com supplies free samples and data sheets..

or, go to a local electrical hardware (MGM electric is good)..everything pre-
packed for you

Most programmable timers have limits to the number of times they can be turned of and on in a 24 hrs period. You will need one that will be able to handle about 85 events. Most are limited all so in the minimum length of time the event can be.

http://www.paragontimecontrols.com/el74_el78_el712_series.htm

One of these should due what you ask

If you want something you can wire straight in (mains supplied), look at so-called Control Relays, such as the Moeller EASY512-AC-RC. Don't know where you're from but the one I cited costs about £90 in the UK.

You'd still have to programme it, but it's pretty simple, using either a PC (cable costs extra!) or the LCD & pushbuttons on the unit.

How much does the job pay?

The simplest way to accomplish your task is to use two timers. The first would be a small dial timer with 96 trippers, each representing 15 minutes. This would allow you to operate the solenoid on 15 minute intervals. You pull the tripper out to activate it, and leave it pushed in for non-operation. This timer is manufactured by Diehl and the model would be a TA-4150. It costs about $42 US. Similar, more expensive timers as manufactured by Paragon are also suitable.

The second timer would be a cube type timer such as a Dayton model 6A857 for about $30 US that has a variable time setting of 30 seconds to 10 minutes. This would accomplish the running time of the solenoid. The first timer would initiate the sequence, and the second would control the length of the cycle.

This set-up should fill your needs very well for less than $100 US.

I agree that you need 2 timers (or oscillators) but I disagree about using 96 trippers.

For the 15 minute oscillator relay which is also $42, this would work:
http://web4.automationdirect.com/adc/Shopping/Catalog/Relays_-z-_Timers/Fuji_Timer_Relays_1-z-16_DIN_(MS_Series)/MS4SM-AP-ADC

For the super cheap 24 hour oscillator at less than $10, this timer would work:
http://www.westsidewholesale.com/index.cgi?pid=970825&CATEGORY=377&source=ad1

Should be under $100 total with shipping at these prices.
Of course you could always build your own 15 minute oscillator using a 555 timer circuit. Diagrams are abundant on the web and I always enjoy building my own. Not to mention the savings in cost. Actually though, if you build your own you will need three timers. One for 24 hours, one for 15 minutes and one for 60 seconds which is still possible with an extra 555 timer circuit. Come to think of it, you may need an additional time delay relay set to delay "off" for you parameters anyhow. Not sure though.

Regards,

Keywalker

The more I think about the more I realize that what you want is not really very simple at all. You are talking about 3 different timing parameters, 24 hour on/off, 15 minute on/off and 60 second delay off. This could get expensive.

Keywalker, don't be so quick to chastise yourself. I believe the answer you gave does, indeed, solve the problem as asked. The key wrod in the problem is "every". He states that he wants to turn on the sprinkler "every" 15 minutes and run for 60 seconds. What you have proposed will do that and with the timer you proposed. My solution, using the electromechanical timer with 96 trippers, would allow him to operate the sprinkler "any" 15 minutes.

By pulling out the appropriate pins, he could, for example, cause the sprinkler to operate, let's say at 7:00 am, then again at 10:00 am, and yet again at 1:00 pm, etc. for the duration of the day. At each of these times, the sprinkler would operate for 60 seconds on the second timer, then shut off, awaiting the next time setting. With the timer you proposed, the sequence would be such that the timer would turn the sprinkler on "every" 15 minutes (which is how the question was phrased) until it would be manually shut off.

People, including myself, tend to use or suggest that with which he is familiar. I have used the two timers I offered in many applications. I didn't search for others. I appreciate your finding that timer and suggesting it. I am sure I can use it in the future. Thanks.

You know, the more I think about my suggestion, I see that I would not be able to do as the question asks, either. He wants to operate the sprinkler "every 15 minutes from about 9 AM to 7 PM" With the electromechanical timer I proposed, he would only be able to operate the sprinkler every OTHER 15 minutes since the second timer would time out and have to be re-energized to accomplish the task. That would require operating the timer every other 15 minutes, as I said.

However, if we use a 15 minute repeat percentage timer for the secondary timer, it would operate for a percentage (6.67% to get 60 seconds) then shut off and repeat for as long (9 am to 7 pm) as power is supplied to it. That would do the job as requested.

I think what is needed is a timer that will turn on for 60 seconds then off for 14 minutes repeatedly. I am not sure I read the question right the first time. A timer like this in conjunction with the super cheap 24 hour oscillator ( http://www.westsidewholesale.com/index.cgi?pid=970825&CATEGORY=377&source=ad1) should do the trick. I will search again to see if I can find such an animal at a reasonable price. Unfortunately, the flicker mode on the relay I originally proposed has the same off time as on time, hence, the need for a third timer.

OK, I get it now. That is what you are talking about when you say repeat percentage timer, right? Do you know of one?

This one seems to fit the bill for the ability to adjust both the off and on cycle timing but I don't know the cost yet.

http://www.airotronics.com/site/product-repeatcycle_TGKD.php

I will try to check further.

This one also looks promising. Still don't know the cost though. You could call for a quote using the number supplied on the page though. NTE is a well known supplier of electronic parts.

http://www.nteinc.com/relay_web/pdf/R26.pdf

No, I don't think the timing is right on the last one. The range does not seem to be sufficient to allow for both 1 minute and 14 minutes on the same range setting... still looking.

Ok... this one will definitely work:

700-HRF Twin Timer

http://www.ab.com/industrialcontrols/products/relays_timers_and_temp_controllers/general_purpose_timers_and_counters/700-hr.html