question about previous circuit design by john fields

[Wayne]

In a previous thread (which google groups will not let me post to),
John Fields designed a circuit for me that is working great:
http://groups.google.com/group/sci.electronics.basics/browse_frm/thread/bbb66379544dfcd2/#

I want to add a fourth output to this circuit that will be always on,
unless the the timer pause button is pressed, at which time that fourth
circuit would shutoff for the same amount of time as the other 3, then
restart like the others. What do I need to add to the circuit to
accomplish this?

 

[John Fields]

In a previous thread (which google groups will not let me post to),
John Fields designed a circuit for me that is working great:
http://groups.google.com/group/sci.electronics.basics/browse_frm/thread/bbb66379544dfcd2/#

I want to add a fourth output to this circuit that will be always on,
unless the the timer pause button is pressed, at which time that fourth
circuit would shutoff for the same amount of time as the other 3, then
restart like the others. What do I need to add to the circuit to
accomplish this?

 

[Wayne]

Thanks, as always! I'll try this later today.

 

[Wayne]

I tried this, but it's kinda working backwards to what I want. U2-13
isn't going hight until I press S1, when I release S1, it goes low.

 

[Wayne]

I meant to say, it's low until I press S1, then it goes high until the
delay finishes, then it goes low again; it's opposite of what I want.

 

[John Fields]

I meant to say, it's low until I press S1, then it goes high until the
delay finishes, then it goes low again; it's opposite of what I want.

---
Yeah, I got it backwards. The switch switches Vcc, not ground,
duh... Sorry about that.

Connect U2-11 and U2-12 to either U2-4 or U2-8, take your output
from U2-13, and that oughta do it.

 

[Wayne]

That did it, but brings up another question. Prior to this change, the
circuit almost always started in the correct state and would start
cycling the pumps immediately. Now that I've made this change, so far,
it always comes up as if S1 has been pressed and I have to wait for the
~30 minutes to lapse and then it starts up as normal. Is there a
modification that will make it always come up correctly?

Thanks again, this is a great little circuit

 

[John Fields]

That did it, but brings up another question. Prior to this change, the
circuit almost always started in the correct state and would start
cycling the pumps immediately. Now that I've made this change, so far,
it always comes up as if S1 has been pressed and I have to wait for the
~30 minutes to lapse and then it starts up as normal.

---
I'm surprised. It should _always_ have come up in the paused
condition...
---

Is there a
modification that will make it always come up correctly?

---
Yes. I've emailed it to you and posted the circuit to abse in case
anyone else is interested.

Just as an aside, in order to make sure the circuit works properly
it would be a good idea to put a 0.1µF cap across Vcc and ground at
each of the chips, and a larger cap (say 100µF or so) across the
supply where it connects to the board.
---