timer circuit to activate a relais every 30 min for 1 min.

[bernd14]

timer circuit

hello,
I need a circuit to activate a relais every 30 minutes for 1 minute. Input voltage can be 12 or 24V dc.
Hope somebody can help. Thanks!

 

[kabiru]

Re: timer circuit

please explain what u meant by I need a circuit to activate a
relais every 30 minutes for 1
minute.

 

[bernd14]

Re: timer circuit

Hello,
I need to activate a circulation pump for solar hot water on a boat by a relais. The pump should run for max.1 minute, then stop for about 30 min. During that time the water will be heated by the sun. When the pump runs the water will be circulated to bring colder water into the solar system, and so on. This cicle should continue until switched off in the evening.
I checked circuits with the 555 chip but did not find what I am lookung for. Another chip would be CD4060 but also there I could not find what I need. I thought there would be some simüple way to build it but it seems to be more difficult than I thought.
I have 12 and 24 volt dc available.
Bernd

 

[IanP]

Re: timer circuit

Forget 555s - longer intervals pretty swampy (due to electrolytic capacitor leakages etc) ..
Instead suggest PICAXE-08 microcontroller ..
www.picaxe.com
The "08" is PIC12F629 based, but has such high level commands ( SLEEP, NAP, GOTO, WAIT etc ) that setting up hours long repetitive delays is a breeze ..
Free editor & bubble gum cheap chips ..

The program may look like this:

Start:

high 1    ; output 1 goes high


wait 60   ; keep output1 for 1 minute

low 1     ; output 1 goes low

for w1=0 to 29  ; wait 30 * 1 minute
wait 60
next w1

goto Start

Rgds,
IanP

 

[bernd14]

Re: timer circuit

Hello IanP,
thanks for the prompt reply. That looks good, but I have no clue about a wiring diagram and the parts required. I can assemble the things but I need to know what is to be connected where. May be you know it.
Bernd

 

[IanP]

Re: timer circuit

GETTING STARTED
https://www.rev-ed.co.uk/docs/picaxe_manual1.pdf

MICROCONTROLLER INTERFACING CIRCUITS
https://www.rev-ed.co.uk/docs/picaxe_manual3.pdf

Picture below is assembled from sections of the above manuals, available from:
**broken link removed**
It may be not the final design, treat is as a starting point ..

Rgds,
IanP

 

[bernd14]

Re: timer circuit

Hi IanP,
I downloaded all the pdf-files and will studý them. Than you very much. I hope it will not be too complicated for someone like me who only knows the basics. I understand your attachment diagram and will assemble the parts mentioned there. Then I will see - and let you know of course.
Bernd