IC 1c & IC 1d form a non inverting buffer, probably would work without ??
I think thats why I added a big OR gate to 4017 outputs to make it look like a bar graph Maybe Bill Marsden can tell us if we need to invert unused stages in the decoding; I think it is possible to get an unwanted early count.

SO what I drew up and posted in post #19, may not work?

 

I'm a bit rusty on decoding, but believe 1880 would be 1880 -1024,Q11,=856-512,Q10,=344-256,Q9,=88-64,Q7,=24-16,Q5,=8-8,Q4,=0. Not used 128,Q8, & 32,Q6. Input Qs 11,10, 9, 7, 5, &4 into an 8 in NAND, 74C30; invert Q8 & Q6 ,input to last two NAND inputs. Invert NAND output & connect to reset & as count in to next IC. On count 1880, the inverted output goes high, resetting counter & providing a 2 cup count pulse. If using 4017 , input pulse is correct polarity, pos going. A BCD counter-7 seg decoder can be connected in parallel with 4040 to give 2 cup incriments on readout. To have display show actual no of cups, decode 1 cup count & then divide by 2 , giving two outputs , one for each counter, 4017 & 7 seg.

Okay, after working with logic a bit and looking at the definitions of all these logic chips, I understand what you said here! So, if this will be more stable, I might draw this up and try it out, as I think I follow it all now. I'm not sure why you said to use an 8 in NAND, and then invert it, instead of using an 8 in AND, but it doesn't matter.
I'll skip the DIP switches as I can't visualize how they fit in the picture...
I think I'll go ahead and buy some of these chips, and experiment. Oh, what about the CD74C30 chip. ...I was using all 4000 series chips because I thought they were better, but this 7400 series chip will work in here? I have a 12 Volt supply.

thanks again

edit, I read this:
"For most new projects the 74HC family is the best choice. "
Maybe I should go with all 74HC and a 5 volt voltage regulator? Any recommendations on that?

 

Only the 4000 series CMOS chips can use a 12 volt supply. All the 74XX chips are limited to 5 volts.

You can use the chip name as a search term to get a data sheet for it.

 

Assuming you are counting up, a simple diode AND gate will detect whatever number you are after (ignoring the 0's).

If you are counting down, a simple diode OR gate will also detect whatever number you want (ignoring the 1's).

If you want to detect a specific number that is randomly appearing, then a AND gate with inverters for the 0's will do the trick.

Bill has already answred decoding question on third line about a specific number. On post 19, if only one sw , or if selected sw's are all consecative, it will work, but for 1880 the 128 & 32 would need to be inverted & applied to the AND, or NAND gate, IC or diode. The noninverting buffer does act as a short delay to stretch the reset pulse.
Not covered yet is how to start & stop valve. Is power on all of the time, or just on to start tank filling? Might use a flip-flop; push button sets, opening valve , 5 pole sw out resets 4017 & inhibits 4040.

 

4xxx & 74C IC are interchangeable functionally but check pin-out, & can use 12V.[ don't forget the " C " ]. Here is an outline of F-F ckt.

 

Wow, I have avoided 74Cxx logic as I mistakenly thought it was limited to 5 volts.

 

Thanks folks. I'll be gone a few days, but sounds like I've got most of my anwsers covered now!

 

I've read this several places in my learning, and wonder if it will be a problem with my 4040 ripple counter?

...In most circuits the ripple delay is not a problem because it is far too short to be seen on a display. However, a logic system connected to ripple counter outputs will briefly see false counts which may produce 'glitches' in the logic system and may disrupt its operation. For example a ripple counter changing from 0111 (7) to 1000 (8) will very briefly show 0110, 0100 and 0000 before 1000!


...thanks.

 

4xxx & 74C IC are interchangeable functionally but check pin-out, & can use 12V.[ don't forget the " C " ]. Here is an outline of F-F ckt.

Edited...
Okay the sketch Bernard drew up is finally starting to make sense to me!
I've found this diagram, attatched photo. Will this work for me, if I remove the 10Meg resistors, and connect pin 9 to my momentary start switch, and pin 13 to the rotary 5 pole switch? Are these pins interchangeable?
Do I understand correctly that the 5 poles on the rotary switch will then go to the 5 different clock time outputs? So when the allotted pulse count is up it will throw this side of the flip flop high?
I SURE appreciate all the help I've been given...