I'm willing to replace the 4001 with a 555, if it can do the 20mts timing + a dry pump test too with one chip. Would it be possible by any means?

 

Are you wanting to use a 4060/555 or a 555 by itself. If the later 4 hours is a bit long, but it might barely be possible. If you are wanting the 4060/555 it is routine and easy.

 

I need 4060 for the 4hrs and the 555 for the 20mts. I also would like to know if a dry pump sense is possible for this circuit using the 555 such that it would the output would go low if the pump is dry anytime it runs..

 

What are the indications of a dry pump? If lack of input water, might a float switch keep 555; pin 4, reset, low; or a vane SW on output side. likr an air flow SW with smaller vane.

 

Can anybody pls help me as to why the 4001 in the last circuit I have posted on this thread keeps rattling the relay when the timout set finishes and if still the input is held high? Its like this... If input to 4001 is high, the relay energises and counting starts. at the end of the period, ie 20 mts, if input is low, relay switches of properly and waits till the next high on input, but if the input is still high when countdown finishes, the output oscillates making the relay tap badly. Somebody please help me with this

 

What are the indications of a dry pump? If lack of input water, might a float switch keep 555; pin 4, reset, low; or a vane SW on output side. likr an air flow SW with smaller vane.

would you mind if I reply to this later after my previous query is cleared or it will make the thread totally confusing, sorry for that.

 

OK, your first problem is to come up with a decent sensor for liquid detection. There are many ways to do this. If I had my druthers I would use a stainless steel rod, but baring that a iron rod will work.

The base sensor is as simple as a transistor with the base connected to the metal rod(s) to sense if water is shorting them or not. Don't forget the base resistor.

I assume you just want to shut down the 555 timer if the water goes away. The sensor should feed a logic one into the reset pin of the 555 (pin 4). If this goes to a true 0 then the timing is aborted and the 555 resets.

Sound like what you want?

 

While I forgot to mention this, this circuit needs verified first. It is harder to retrofit something like this after the fact.

 

I assume you just want to shut down the 555 timer if the water goes away. The sensor should feed a logic one into the reset pin of the 555 (pin 4). If this goes to a true 0 then the timing is aborted and the 555 resets.

Sound like what you want?

Exactly, 555 gets powered every 3 hrs or so, triggers monostable mode, starts pumping, if the sense rods detect open circuit, resets the 555 and shuts down. The time between switching on and when water starts to appear at the sense rods will have a few secs delay.. will that be a problem? And using 2 metal rods would be fine.

 

The cutoff when the sensor opens up is more or less instant. Other than that, I'll start drawing.

 

Can anybody pls help me as to why the 4001 in the last circuit I have posted on this thread keeps rattling the relay when the timout set finishes and if still the input is held high? Its like this... If input to 4001 is high, the relay energises and counting starts. at the end of the period, ie 20 mts, if input is low, relay switches of properly and waits till the next high on input, but if the input is still high when countdown finishes, the output oscillates making the relay tap badly. Somebody please help me with this

 

Dear sir
I recently made ​​this circuit : (thanks to ronj)
http://www.zen22142.zen.co.uk/ronj/rt.html

And using this page to demonstrate that the relay is working properly :
http://www.zen22142.zen.co.uk/ronj/rtt.html

Although I've replaced a few pieces , "It works with No problem."

With existing components ، the time it takes from the moment power is applied to the moment the yellow LED lights for the first time is about 27 to 38 seconds depending on R7.
I set it to 30 seconds.(not 60 seconds as described in Ronj page).
So on pin 7 of 4060 I got ~60s delay between the output periods.
(30 for on + 30 for off)
on pin 5 I got ~2 minutes
on pin 4 I got ~4 minutes
and...
but on 4001 side I've changed these values ​​to achieve up to 40 seconds lenght of the output period :
R3 changed to 2M2 ohm
C1 changed to 47 micro farad
I set it to 10 seconds based on my needs.

when the relay energizes everything is good.
but at the end of the countdown (in my circuit 10s and allways the input is still high because of 30s "on" period) relay turns off with some noises and rapid oscillates.

changing :
R2 from 4k7 to 27k
R1 from 1k to 100k
""solved my problem""
my relay is 12v with 400ohm resistance.

I'm so glad if this can help you solve your problem.
Please let me know.
Regards

 

changing :
R2 from 4k7 to 27k
R1 from 1k to 100k
""solved my problem""
my relay is 12v with 400ohm resistance.

I'm so glad if this can help you solve your problem.
Please let me know.
Regards

Woah.. I posted the same question 3 times and none replied and a new member helped me with it Thanks a ton, let me try it. I doubt if it will work, but will surely try as I feel so fishy abt the 1k on the transistor. Even if it doesnt works, I'm thankful for your help

 

Changing R2 to 27k seems excessive unles BC547 were a darlington, not a bad idea. Coupling Q13 to 4001-6 bothers me as Q13 stays high for 2 hours; hence the thumb nail:

 

Changing R2 to 27k seems excessive unles BC547 were a darlington, not a bad idea. Coupling Q13 to 4001-6 bothers me as Q13 stays high for 2 hours; hence the thumb nail:

Changed R2 to 18k and the relay wouldnt turn off at all, you were right. And pin 5 of 4001 still gives a varying output even before it reaches the 547, so that shudnt be the problem. Like you said, the only thing to suspect is the Q13 to 4001. Thank you, will try this

 

@bernard
Sorry to say, but the .1 just wudnt trigger the inputs to 4001. If I short it, relay latches.. Any other ideas?

 

My circuit works perfectly with no problem , except of not disconnecting relay
immediately on the timeout that is solved by changing elements as I said before.
Thanks again to Ronj.
I checked all things about my circuit , chanching ic , relay , transistor , ...
and then found that increasing R2 will cause relay to disconnect immediately.

Are you sure that all parts are ok?
Although this is a simple circuit , but check all wiring again.

Pin 5 of 4001 in my circuit has about 9 volts when it is active and 0 at the end of the timeout.
I use 12v power supply.
Good luck.

 

I can find no fault with 4001 schematic; breadboarded it, shortened timing to 20 sec for convenience & clocked with 555 with 30 sec period. Works fine with direct coupling or capacitive coupling. Ve 8V, pin 5 .1V to 7V with 2.2k load to red LED. Bad 4001? Is Ve well filtered, like 10μF minimum?

 

It was a problem with the power supply. I had used a battery when breadboarded and then when I made the pcb used a 12-0-12 transformer but it gives far too many ripples even with a 1500uf cap. Tested with the battery and runs fine. Adding a 7812 and a bigger cap and project closed. Thanks for all your help!