# yard lights..

Discussion in 'Architecture & Engineering' started by NMSquirrel, Nov 15, 2012.

1. ### NMSquirrelOCD ADHD THC IMO UR12Valued Senior Member

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dunno where else to ask this..

looking for a solar powered yard light..one that has a timer that i can set to 15 minutes to turn off..
solar powered yard lights are easy to find..but all i have found is on all night..no selectable timer..

but i wanna use it as a timer for a sprinkler system..it has to be around 9 volts and either turn off in 15 minutes or the battery can die after 15 minutes..

3. ### billvonValued Senior Member

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Do you want lights as well, or just the timer function?

Do you want to time it from sunset or from a certain clock time?

5. ### NMSquirrelOCD ADHD THC IMO UR12Valued Senior Member

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5,478
its a low tech solution for the sprinklers..if it goes on at dusk/sunset for 15 minutes that would be enough to water the grass..
what i had originally intended was to find a yard light with a timer and just wire the sprinklers into the bulb (bulb would be deleted)

wireing it into 110 wont work, as we have no idea where the previous wiring runs..(there are like 4 different sprinkler timers in the storage shed, so apperantly thats not an option)

i tested a 9 volt battery with it and have it set up now to hook up a 9 volt battery to the valve, so we dont have to crawl into the three foot hole to turn on the sprinklers..(it works either polarity) when the battery is connected the valve turns on, when the battery is disconnected the valve turns off..

as it sets now, we can use a rechargable battery to work it ( i imagine the cheaper rechargables would run down quicker, maybe that would give me my 15 minute run time)..
but that requires hooking that battery up and disconnecting it everyday (season permitting).

the yard light option (maybe there is another option i am missing) would make it no maintenance..wouldnt have to worry about hooking and unhooking the battery.

7. ### billvonValued Senior Member

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14,306
OK then.

Start with a cheap 16V solar panel. Wire it to a 12V DPDT relay. The normally closed contacts will be closed when the sun is down.

Now add a diode, a 13.5V regulator and a 4ah 12V lead acid battery. This will charge from the solar panel and provide power to operate your valve.

Now add a 555 timer to the output of the relay. Configure it for monostable operation. This will allow you to set a run time. 1000uF with a 1 meg resistor should give you about 15-20 minutes. You might need an additional relay at the 555's output to drive the valve.

All the above is available from Radio Shack.

8. ### MacGyver1968Fixin' Shit that Ain't BrokeValued Senior Member

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Or you could use a relay timer like this one:

This one is a "delay on make" used in air conditioners, but they do make timer versions. Just add it in series with the power to the lights and the sprinkler.

9. ### MacGyver1968Fixin' Shit that Ain't BrokeValued Senior Member

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Why does my post need approval by mods?

10. ### MacGyver1968Fixin' Shit that Ain't BrokeValued Senior Member

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Let's try that again:

Or you could use a relay timer like this one:

This one is a "delay on make" used in air conditioners, but they do make timer versions. Just add it in series with the power to the lights and the sprinkler.

edit: this only works with AC...a solar panel will put out DC...so forget this.

11. ### MacGyver1968Fixin' Shit that Ain't BrokeValued Senior Member

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Looking for other options. Couple of quick questions. How many lights do you need, and what's your budget?

Edit:

Ok..it seems that make 2 different kinds. One type has the solar cell built into the light, and others, like this have a separate solar cell:

I think this kind would be easier to modify, as the solar cell, light sensor and battery are all in the solar cell package. You could simply splice into the wire coming out of the solar cell, and add in your timer. Still looking for a "time on make" relay timer that works on low voltage dc.

12. ### billvonValued Senior Member

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Most of these have three NiMH batteries to give you 3.6 volts, which is what you need to run the white LED's in the lamps. So they would likely not work well if he needs 9V.

13. ### MacGyver1968Fixin' Shit that Ain't BrokeValued Senior Member

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What about using that 3.6 volts to close a relay like this?

3.6 volts should be enough to close a 5 volt relay.

14. ### billvonValued Senior Member

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If you choose wisely, yes. DIP relays like the one above have a pull-in voltage of between 3.2 and 4.5 volts; the Panasonic DS2Y-S-DC5V, for example, will pull in at 3.5 volts.

However that doesn't solve his other problem which is that he needs 9 volts to turn his sprinkler valve on.

15. ### scheherazadeNorthern Horse WhispererValued Senior Member

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3,798
Sheesh! I'm shoveling snow and you lot are designing timed self-watering systems. I've considered some for my gardening but because I am on a closed system (water tank with pressure system, pumped in to from a deep well pump on a manual switch with no fail-safes) I don't think that is a good idea. Too risky, might burn out the pump if the tank pumps dry and no one close to hand. My compromise for part of the garden is a soaker hose. I top up the inside tank and then turn on the watering system, set a timer and tend to indoor matters until done.

Interesting to check out the solutions being offered here, nonetheless.

16. ### EnmosRegistered Senior Member

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Squirrel, why do you need the solar powered yard lights? Just hook your sprinklers up to a timer.

17. ### MacGyver1968Fixin' Shit that Ain't BrokeValued Senior Member

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What I was thinking was: The sprinkler has a timer that turns on a valve. Just set the sprinkler to "always on", and place the 5volt relay between the sprinkler timer and the valve. Power the relay with the output of the solar panel/battery/light sensor assembly. When the solar panel and timer activates...the relay closes and the power coming from the sprinkler timer box turns on the valve for the 15 minutes he desires.

18. ### MacGyver1968Fixin' Shit that Ain't BrokeValued Senior Member

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I've never installed a sprinkler system. I did a little research and all of the valves I found run on 24VAC. Squirrel...anyway you have a look at your valves and see what the voltage is? Where did the 9 volt number come from?

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20. ### kwhilbornBannedBanned

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@ Billvon, and all