Could you please help me
I need to build a timer circuit that works for 15 to 30 minutes every day , which means that it should be off for almost 24 hours and then it is on only for 15 minutes then it is off again
The point is that i don't wanna use arduino or anything complicated to program it
Just a simple circuit , as simple as possible
I was thinking about using 555 timer but it is impossible to get the supposed duty cycle
Could u help me find a simple circuit that works like that ?

 

One suggestion: make an NE555 run with one cycle every 24 hours then trigger a second timer from it. This second timer has a variable pulse width of 15 to 30 minutes.

 

One suggestion: make an NE555 run with one cycle every 24 hours then trigger a second timer from it. This second timer has a variable pulse width of 15 to 30 minutes.

I actually thought about that but i couldn't figure out how to build the circuit

 

hi Ghina,
E-Bay sell these timers approx £6 GBP, they are a simple way to provide the 24Hour timing, use 555 CMOS timer for the 15 > 30-minute timer.

PDF attached.

E

 

Does the circuit need to be triggered at exactly the same time each day? Because if that is the case, what you need is not a simple timer but a clock, and ‘555 ain't gonna do it.

 

Hi,
It will be difficult to get long time spans with the 555'. 10 minutes - that's the maximum.
You better study the CD4060 IC datasheet, this chip can be used with a quartz resonator or with an RC circuit. Two such chips can be cascaded, too.
Pay attention to post #5. It's possible that the version with a quartz resonator will work better for your task

 

Are you opposed to purchasing a programmable timer? If so:
https://www.lowes.com/pd/BN-LINK-BN...-Programs-1-Pack-15A-1875W-ETL-Listed/9481306
I have a much older version of this timer. It can be programmed to come on at a given time and then off at a later time. It can run for as short as 1 minute; so you can set this to run for as long as you want. You can choose which days of the week it comes on and can program (on mine) up to 9 "On and Off" times.
This is for indoor use. I have two of them. One is set for Daylight Savings time while the other is set for Standard time. For me it's much easier to unplug one in and plug in the other. Quicker and easier than building your own. Of course I understand if you have the desire to build your own, this is merely a suggestion.

Lowe's building supply stores are located in the United States. I see someone made a recommendation for something offered at a price of 6 Lyra. (forgive any misspelling).

 

Certainly there are quite a few different schemes available, and a whole lot depends on the accuracy requirements. Besides that, a lot also depends on the resources that the TS has available. There is also a BIG QUESTION about what sort of useful output the time switch has: "then it is on only for 15 minutes then it is off again" . What does that actually mean in volts and amps controlled (switched on and off)??

 

As covered in many past threads, nothing hits the combination of low cost and low effort like a lamp timer powering a 5 V (or whatever logic level you want) wall-wart.

If you really want to build something, we are all for that and are here to advise.

What is the signal for? What does it drive? What is it you are trying to achieve?

ak

 

You can buy a mechanical timer that looks similar to this.



When I was a teenager, I built a timer using an old style alarm clock.

 

I need to build a timer circuit that works for 15 to 30 minutes every day , which means that it should be off for almost 24 hours and then it is on only for 15 minutes then it is off again

Well, it would be good to know how the TS timer is going to be used. What voltage? What current? Indoor or out? Otherwise we're guessing. I'm all for building timers. But for a 24 hour timer - that's a big span of time for a 555.

 

Well, here's one that is battery controlled. With a little modification can be used to control some mystery device:
https://www.amazon.com/dp/B00GGBGG3W
Expensive though.

EDIT: After reviewing the associated video it is a pulsed ON / pulsed OFF Latching solenoid. That means it uses energy just long enough to turn the valve on. Then when the end of the cycle is reached it uses enough energy just long enough to turn the valve off. So this probably won't work for what you want. Unless your purpose is sprinkler control. Which we don't know yet what purpose you want to serve.
END EDIT

 

It will be difficult to get long time spans with the 555'. 10 minutes - that's the maximum.
You better study the CD4060 IC data sheet, this chip can be used with a quartz resonator or with an RC circuit. Two such chips can be cascaded, too.

This would seem like a fairly good approach. But how critical is the timing? Same time every day with a variance of only a few seconds? Again, Indoor or out? Till I hear from the TS - I'm staying quiet for now.

 

You can buy a mechanical timer that looks similar to this.

I have a box full of 24 hour mechanical times where the on/off can be set for each 15 minutes in a day. New. For 120V 60hz.

 

If it's for operation from AC mains, you can just use a smart plug which can be programmed through its app for any desired on and off periods.

 

I have a box full of 24 hour mechanical times where the on/off can be set for each 15 minutes in a day. New. For 120V 60hz.
View attachment 370227

I have a few similar to that. Only mine are in 30 minute increments. Almost two decades ago I set up a garden in the basement for my wife's outdoor plants. When winter comes the plants are brought inside and placed over a tote full of water. Using a 12 volt pump and 12V power supply the water would run for 30 minutes once a day. That didn't last long as the pump burned up. It was a windshield washer sprayer pump, meant for intermittent use. Running for 30 minutes was too much for it. I later took a dish washer drain pump and attached it to the outside of the tote with an overhead tank and drip tubes for the plants. Again, running for 30 minutes was tough on the pump. Its original meantime was on the order of maybe 5 minutes. After a while that pump failed. My wife's plants died, so the whole rig sits in the garage, likely never to be used again. But since I have a few programmable timers I could set it back up once again. Unfortunately I don't have the desire to do so. Her plants now go dormant during the winter and come back in the springtime.

 

AND WE STILL DON'T HAVE DETAILS.

 

Could you please help me
I need to build a timer circuit that works for 15 to 30 minutes every day , which means that it should be off for almost 24 hours and then it is on only for 15 minutes then it is off again
The point is that i don't wanna use arduino or anything complicated to program it
Just a simple circuit , as simple as possible
I was thinking about using 555 timer but it is impossible to get the supposed duty cycle
Could u help me find a simple circuit that works like that ?

This application is precisely what an Arduino was designed for. I'm not certain that your contention that they are "complicated" is a defensible position. If you still think so, I would be interested in your particular reasons including personal limitations of which I might be unaware.

 

The old fashioned way:
If you clock it off the mains you need to divide by 4320000.
it factors are 2^8 x 3^3 x 5^4 .
you can combine each of the ÷5 sections with a ÷2 section to make a ÷10, and you can combine two ÷3 to make a ÷9. That leaves a ÷3 and four ÷2.
A 4024 will take care of the four ÷2 sections, and seven 4017s will do the rest, four ÷10, a ÷9 and a ÷3 .

or if you start from a 32.768kHz crystal, it 2^22 x 5^2 x 3^3.
Cd4521 will make the crystal oscillator and divide by 2^20, then Divide by 10 twice, by 9 once and by 3.

 

Ebay have some ready built time switches that will probabley do what you require.
This is a link to one advert. https://www.ebay.co.uk/itm/236919999412?
Les.