looking for a timer

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moe
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looking for a timer

Post by moe » Sat Aug 01, 2020 5:40 pm

I am looking for a timer that will only close / energize for 15 sec once every 24 hours. low current 120 vac or 12vdc
any suggestion?
thanks

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CeaSaR
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Re: looking for a timer

Post by CeaSaR » Sat Aug 01, 2020 6:46 pm

What do you need to switch? Commercially available or kit/home-made?
That would help us figure out the best course to follow.
Hey, what do I know?

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Janitor Tzap
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Re: looking for a timer

Post by Janitor Tzap » Sat Aug 01, 2020 9:10 pm

Moe,

Most commercially available electric analog programmable timers can only do 30 to 15 minute intervals.
Most commercially available electric digital programmable timers can only do 1 minute intervals.
CeaSaR wrote:
Sat Aug 01, 2020 6:46 pm
What do you need to switch? Commercially available or kit/home-made?
That would help us figure out the best course to follow.
I agree with CeaSar,
What are you trying to switch on for such a short time period?


Signed Janitor Tzap

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jwax
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Re: looking for a timer

Post by jwax » Sun Aug 02, 2020 9:03 am

Cascaded dual timers could probably manage this- ICM7556 perhaps.

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Externet
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Re: looking for a timer

Post by Externet » Sun Aug 02, 2020 9:28 am

A junk VCR could be a donor of its clock / timer set to "record" a daily program, firing a 15 second trigger.
Never played with an orphan smart phone with no service and set its clock alarm to audio-trigger something...
- Abolish the deciBel ! -

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CeaSaR
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Re: looking for a timer

Post by CeaSaR » Sun Aug 02, 2020 9:43 am

Really, it comes down to Plug-n-Play or custom.

From the criteria in the OP, it seems that a custom unit, either discrete or software based would be the best option. It really depends on how accurate the time needs to be. Software is probably the most accurate and the easiest to implement for most people. Hardware would need some fiddling to keep it on track. Either way, you could set it up so that once the 24 hr time period is recognized, a one-shot 15 sec pulse could be achieved via many means. Depends on your level of involved interest.

Also, the intended use will determine if "home brew" will even be allowed (ie, not home/personal use).

Still, we'd need a little more insight to better help.
Hey, what do I know?

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jwax
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Re: looking for a timer

Post by jwax » Sun Aug 02, 2020 10:13 am

A $9 Arduino Nano would do the job also.

sghioto
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Re: looking for a timer

Post by sghioto » Mon Aug 03, 2020 5:11 pm

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gerty
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Re: looking for a timer

Post by gerty » Tue Aug 04, 2020 2:09 am

Strange !!! I haven't dealt with MPJA in years... Today I see this and get a sales flyer from them !! What are the odds..

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CeaSaR
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Re: looking for a timer

Post by CeaSaR » Tue Aug 04, 2020 6:12 am

So the MPJA unit has 1 minute resolution on the output. which means you'll still need something like a 555 One-Shot set to trigger for 15 seconds on startup to drive another output for the load.

It's that short on-time that is the hardest thing to deal with commercially. That's why I figured it would be a custom (at least partially) build.

Of course a small Microcontroller would do all that with minimal external parts, as long as your programming skills are up to it.
Hey, what do I know?

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Janitor Tzap
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Re: looking for a timer

Post by Janitor Tzap » Thu Aug 06, 2020 8:50 pm

Okay,

After much web mining I found this....
Image
It has the programmable Seconds intervals that you need.
And it isn't too expensive.
https://www.wish.com/product/5e691c94c9 ... &share=web


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sghioto
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Re: looking for a timer

Post by sghioto » Fri Aug 07, 2020 11:42 am

Nice find. Available through Amazon but delivery sometime in October. :sad:
Steve G

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dacflyer
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Re: looking for a timer

Post by dacflyer » Tue Aug 11, 2020 8:39 am

here at my work we use a timer for the school flashers. they can be set to turn on or off, and a 1 second pules. I guess they can be used for school bell ringers as well,
it's nice that they have a holiday scheduler as well.
but obviously it wouldn't work for your needs..

google ----> school bell ringer / timer
all kinds of stuff comes up.. might be of some help..

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Lenp
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Re: looking for a timer

Post by Lenp » Tue Aug 11, 2020 10:34 am

Connect any clock timer's output that can be set for the 24 hours, to a one shot relay set for the 15 seconds interval. If the15 seconds does not need exact timing, look at the ICM line of cube timers that are used in HVAC controls.
Len

“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)

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