Please help me out with this circuit

[ericgibbs]

hi mocucz,

This has been modified to give a high on only one pin at a time.

Check it thru.
Note: the 74LS25 is a dual 4 inp NOR

 

[mocuZ]

Hi, ericgibbs,
Thanks again. So here's your idea: Control.pdf.

First: I couldn't find 74LS25 so I changed it with SN74HC4002 (again dual
4-input positive NOR gate).
Second: At the triggers' outputs you see "Port#". I'm placing a buffer
(SN74LS541N - Octal Buffer and Line Driver with 3-State Outputs) on each
of the outputs. So that I can send positive impulses to as many switches
as I want. In my case: the greates amount is 4 (MAX333). On each of
the switch inputs there's a pull-down resistor tied to GND.

What's you opinion?

 

[ericgibbs]

Hi, ericgibbs,
Thanks again. So here's your idea: Control.pdf.

First: I couldn't find 74LS25 so I changed it with SN74HC4002 (again dual
4-input positive NOR gate).
Second: At the triggers' outputs you see "Port#". I'm placing a buffer
(SN74LS541N - Octal Buffer and Line Driver with 3-State Outputs) on each
of the outputs. So that I can send positive impulses to as many switches
as I want. In my case: the greates amount is 4 (MAX333). On each of
the switch inputs there's a pull-down resistor tied to GND.

What's you opinion?

hi,
One small point, you have the switch resistors to +5V, should be 0V.

I'll look at the MAX333 input loading, it looks as a the LS374 should drive the MAX [4] directly without a LS541.

 

[mocuZ]

My bad. I'll fix that up.

 

[ericgibbs]

My bad. I'll fix that up.

hi,
I would try to get a 74HCT4002, checking the 74HC4002 suggests the output low will not be low enough for the LS input

Check this link:
Logic Voltage Thresholds for TTL, CMOS, LVCMOS, and GTLP IC's

EDIT: I am checking this low margin, I dont normally use the HC range, just the HCT which are compatible with LS.

RE-EDIT: done a bit more homework... there is not a problem HC to LS

 

[mocuZ]

I read the link. Again my mistake for not paying attention to something so important.
I tried finding "LS NORs", but then I read your edit and ... relief myself. Thanks.

Is there a way I can send you "the whole picture"? May be e-mail?

 

[ericgibbs]

Is there a way I can send you "the whole picture"? May be e-mail?

hi,
You could attach to a post or is it confidential.?

 

[mocuZ]

So ... there it is: switch.zip
Feel free to ask whatever you think of.

 

[ericgibbs]

So ... there it is: switch.zip
Feel free to ask whatever you think of.

hi,
Looked thru all the ccts, wow!.
The Control pcb section looks OK.

The pcb layout is going to be 'interesting', I would say multi-layer without a doubt.

Let me know when its up and running.

Good Luck.

 

[mocuZ]

Yah. As I was looking the drawings this morning I realised that the PCB is
going to be at least with two layers. Even if I use SMD components, it's
going to be again two layers at least.
Do you have any comments or sujestions on the other sheets? Something
missed by me that you've spotted? Wrong connections? Anything.

 

[ericgibbs]

Yah. As I was looking the drawings this morning I realised that the PCB is
going to be at least with two layers. Even if I use SMD components, it's
going to be again two layers at least.
Do you have any comments or sujestions on the other sheets? Something
missed by me that you've spotted? Wrong connections? Anything.

hi,
I'll look thru the other sheets, give me a while, come back to you.

I would say at least a 4 layer pcb, is each drawing going to be on its own pcb.?

Its not the components, but the 'many' tracks.

 

[mocuZ]

OK. Take your time.

My first idea was to put all the stuff on a single board. But ... now I'm
considering two boards: one for the switch and the other for the buffers,
the logic and the power supply. I'll try do the boards with equal physical
dementions and put some connectors between them.In that way I'll save
some room (I suppose), the device wolud look compact and it'll fit in much
more normal box.

But before doing the boards I have to finish up the buffer part and make
the corresponding conncetions.

 

[mocuZ]

Yatsi!
I am done with the first (switch) board.
Now I'll do a little break and after a day or two I'm starting the second board (control).

 

[mocuZ]

Hi, ericgibbs,
While we were discussing the control unit I missed telling you (my bad again)
that I might (and certainly will) need a "RESET" button. I didn't mention that
part, did I. The idea is whenever pressed this button will set the switch
in "straight-trough" mode where every input port responds to its output one.
The other tiny detail I didn't metion too is the buzzer. When pressing a
button a short beep is produced. Just as some kind of (sound) indication.
Here's the switch board :

 

[ericgibbs]

Hi, ericgibbs,
While we were discussing the control unit I missed telling you (my bad again)
that I might (and certainly will) need a "RESET" button. I didn't mention that
part, did I. The idea is whenever pressed this button will set the switch
in "straight-trough" mode where every input port responds to its output one.
The other tiny detail I didn't metion too is the buzzer. When pressing a
button a short beep is produced. Just as some kind of (sound) indication.
Here's the switch board :

This addition will give a bleep while a button is pressed, the bzr is the type that sounds when 5V is applied.

I dont understand the RESET requirement, can you explain a little more.?

 

[mocuZ]

So ... you the switch does 1->1, 2->2, 3->3, 4->4. The you decide you another
pattern and you press for example S4: 1-3, 3-1, 4->2, 2->4. After a while you decide
you another pattern and so on. After you've done a few patterns you decide that you
need to go back at the start condition where 1->1, 2->2, 3->3, 4->4. And right there
you press the RESET button which sets all the switches on the big PCB in there normal
state so that you can come with the 1->1, 2->2, 3->3, 4->4 mode.
I hope I was useful. If not, I'll try explain it better.
Any cometary on the board? One thing you can say at first sight: It's HUGE!

 

[ericgibbs]

hi,
You do realise that only one output will be set at any one time, there will be no pattern.?

Example: If I press switch #1 of group #1 this will ONLY set output #1 of 74LS374 High, ALL the other outputs will be Low.

If I now press Sw #3 of group #3, ONLY output #3 of group #3 will go High, ALL other outputs will go Low.

This will happen because the three LS374 are clocked from a common clock.

If you want to control each LS374 separately, you must have individual clocks for each LS374.

Is that what you are expecting.?

 

[mocuZ]

OK. Once again:
When I press S1 an impulse come out at the other side. I take that impulse and send it
to the inputs of a buffer. At the outputs of the buffer I have that same impulse eight
times. Eight equal impulses.
With these same eight outputs I go to every single switch I want to "power on".
And that's how I have "patterns". And that's how a single button does a certain pattern.

 

[mocuZ]

Sorry about the stupid question, but I just want to be sure I understand what
you've drawn. So SN74HCT14N is a Hex-Schmitt-Trigger Inverter right?
The other thing is a diode, may be. But I am not sure because I can't
see it right. But I think you've placed a diode (1N4007 for example)
right between pin 2 and pin 3; anode goes to 2, cathode goes to 3?

 

[ericgibbs]

Sorry about the stupid question, but I just want to be sure I understand what
you've drawn. So SN74HCT14N is a Hex-Schmitt-Trigger Inverter right?
The other thing is a diode, may be. But I am not sure because I can't
see it right. But I think you've placed a diode (1N4007 for example)
right between pin 2 and pin 3; anode goes to 2, cathode goes to 3?

hi,
Its a signal diode, 1N914 or 1N4148.

It is a hex schmitt invertor.