Help with a timer

[Malakesher]

Hello let me start straight away by saying I know very little about electronics as I’m sure you will notice. I have been looking through your FAQ and at some of the site linked. I am trying to learn.

Anyway I started this whole learning electronics because I want to modify this timer I have (or rebuild from scratch if there are a lot of changes).
**broken link removed**

Anyway this allows me to pulse for up to 5 seconds and then pause for up to 60 seconds then repeat. Now I need to improve these lengths of time and as far as I understand using higher resistance potentiometers (I hope that’s spelt right) would do this.

So first of all is that correct?

Then secondly I want to up the times to 10 mins pulse and 7 hours pause which is a huge leap, and I'm totally guessing here, but that may be too much of a stretch for just changing the pots.

So is there anything else I should change on this to achieve what I'm after?

Here is the build guide I hope it has all the information that you need to help me.

**broken link removed**
Link to full manual

Thank you very much for helping and if there is anything else you need to know I do have the timer with me so if the information is on a component I can tell you it.

 

[ericgibbs]

hi,
Looking at the link, I would say that over a few tens of minutes delay is not possible with any changes to this module...

 

[Malakesher]

Ah. Ok well would it be possible to build something similar from scratch that would do the job?

 

[ericgibbs]

Ah. Ok well would it be possible to build something similar from scratch that would do the job?

Yes its possible do that, give us some details of what you want to switch.
ie: Voltage/Current AC/DC etc and what will be control voltage that operates the switch.

 

[Malakesher]

The switch will be operated by a 12V battery and it will be controlling the power to a water pump powered from the same battery.

The battery is a sealed lead acid 12v 7.2A battery.

Although the battery was based on the fact that the current switch needs 12V power it would be better for me to use a 6V 12A battery unless that causes many problems.

 

[ericgibbs]

hi,
If you can source a UA2240 timer IC, it can be programmed for hours or days.

 

[Malakesher]

It looks like I can get one of those but I have no idea how I would use it.

Thanks a lot by the way for helping me.

 

[Malakesher]

I came across this and it seems like it could do what I need but it is still a little out of my knowledge so could I just ask if this could do what I need and then I will spend a little more time trying to figure it out.

 

[ericgibbs]

I came across this and it seems like it could do what I need but it is still a little out of my knowledge so could I just ask if this could do what I need and then I will spend a little more time trying to figure it out.

hi,
This a typical Astable circuit [ like the Maplin device]
The basic timing oscillator is set by pin 13.

The outputs are pins 1 thru 8.

You would set the basic time rate so that it gives a 10min pulse every 7 hours.

The circuit requires redrawing to suit your application, at the moment I am tied up on another project.