# A control problem

Discussion in 'Electronic Basics' started by rollajarhead, Mar 25, 2005.

Hi

I am having trouble working out a solution to a control problem. What I
have is four (4) inputs needing to control six (6) outputs.

The inputs are, "Zoom", "Focus", "Menu" and "Common".

The outputs are, "In", "Out", "Near", "Far", "Menu"
and "Ground".

The two inputs, "Zoom" and "Focus", have momentary switches
(normally open) "In", "Out", "Near" and "Far" in that
order, corresponding to them. Input "Menu" has a switch aptly named
"Menu" and there is no switch with "Common".

Pushing a switch determines the input combination. Example, I push
"In", input "Zoom" is 12v DC and input "Common" is ground.
All other inputs stay at 0v DC. However there is about 150mV DC on
each. Now I push the switch corresponding to "Out", input
"Zoom" is now ground and input "Common" is 12v DC, all others
are as described as before.

Inputs "Zoom", "Focus" and "Common" have three states each,
12v DC, 0v DC and ground.

I have tried using diodes, transistors (NPN, PNP) and have looked at
logic combinations until I see 1's and 0's in my sleep. So I have
turned to those of you who are more capable then I to solve this
problem

Thank you in advance for any insight you may be able to give me.

Thanks,

2. ### John FieldsGuest

---
I'm a little confused, but ISTM that if you have five switches and
various things that you want to happen when you push the switches,
they can be described in a matrix, like this:

SWITCH OUTPUT CONDITIONS
PRESSED
ZOOM FOCUS COMMON MENU
--------+--------+--------+---------+-------+
NONE | | | | |
--------+--------+--------+---------+-------+
IN | +12 | 0V | GND | 0V |
--------+--------+--------+---------+-------+
OUT | GND | 0V | +12 | 0V |
--------+--------+--------+---------+-------+
NEAR | | | | |
--------+--------+--------+---------+-------+
FAR | | | | |
--------+--------+--------+---------+-------+
MENU | | | | |
--------+--------+--------+---------+-------+

I've filled out what I think you want for the IN and OUT button
pressed conditions, so if you could fill out the rest of the entries
that would give us an idea of what needs to happen when the other
switches are pressed.

Also, what do you want to happen if more than one switch is pressed at
the same time?

3. ### Rich GriseGuest

At this point, I become hopelessly confused.

First, you say you have four inputs, Z, F, M, and C.
Then you say, Z and F have momentary switches I, O, N, and F.

That's ten inputs, so far.

I need a picture. (or at least an ASCII diagram.)

Thanks,
Rich

Below is the matrix filled out and as to what happnes if more then one
switch is pushed the controler will not allow it.

SWITCH OUTPUT CONDITIONS
PRESSED
ZOOM FOCUS COMMON MENU
--------+--------+--------+---­------+-------+
NONE | | | | |
--------+--------+--------+---­------+-------+
IN | +12 | 0V | GND | 0V |
--------+--------+--------+---­------+-------+
OUT | GND | 0V | +12 | 0V |
--------+--------+--------+---­------+-------+
NEAR | 0V | 12V | GND | 0V |
--------+--------+--------+---­------+-------+
FAR | 0V | GND | +12V | 0V |
--------+--------+--------+---­------+-------+
MENU | 0V | 0V | GND | +12V |
--------+--------+--------+---­------+-------+

More information on this problem, I have a control unit built by one
company and a camera by another and I am trying to solve the interface
problem.

Thanks again

I am sorry if I used the wrong terms. What I have is a control unit,
some cable, a pan/tilt head, housing and a camera. I called the wires
coming to the camera inputs I guess I should have called them wires.
The inputs are in the control unit, "In", "Out" share the wire
"Zoom", while, "Near", "Far" share "Focus". The wire
"Common" changes in accordance with the input; +12V for "In"
and "Far", and GND for "Out" and "Far".

I hope this explains the problem if not I will attempt an ASCI drawing.

Thanks again.

6. ### John FieldsGuest

---
OK. If that's the matrix for the camera, the columns should be
labelled "INPUT CONDITIONS" since that's what you have to put _into_
the camera in order to make it do what you want it to. What I've got
so far, then, is that you have a camera with four control inputs which
look tike this:

+--------+
ZOOM>-------| |
| |
FOCUS>------| |
| |
| |
COMMON>-----| |
+--------+

Also, from the table, it looks like if you want it to zoom in you
connect +12V to ZOOM and GND to COMMON, but if you want it to zoom out
you connect +12V to COMMON and GND to ZOOM and let everything else
float. In other words, +12V is one end of a 12 volt supply, GND is
the other end and 0V means that neither end of the power supply is
connected (those wires float, with nothing connected to them). Is
that correct?

From your earlier description of the controller, it seems to be no
more than a box with five switches on it and some means of bringing
out those switch closures, but you don't mention how the switches are
wired. One way would be like this:

+-------------+
| |
| ZOOM |O-------> ZOOM IN NO
| IN |O-------> ZOOM IN COMMOM
| |
| ZOOM |O-------> ZOOM OUT NO
| OUT |O-------> ZOOM OUT COMMON
| |
| FOCUS |O-------> FOCUS NEAR NO
| NEAR |O-------> FOCUS NEAR COMMON
| |
| FOCUS |O-------> FOCUS FAR NO
| FAR |O-------> FOCUS FAR COMMOM
| |
| |O-------> MENU COMMON
| |
+-------------+

Another, like this:

+--------------+
| |
| ZOOM |O-------> ZOOM IN
| IN |O--+ |
| | |
| ZOOM |O--|-----> ZOOM OUT
| OUT |O--+ |
| | |
| FOCUS |O--|-----> FOCUS NEAR
| NEAR |O--+ |
| | |
| FOCUS |O--|-----> FOCUS FAR
| FAR |O--+ |
| | |
| |O--+-----> COMMON
| |
+--------------+

Or, perhaps, some other way. Without knowing it will be impossible to
work up an interface for you.

OK. If that's the matrix for the camera, the columns should be
Correct again.
This looks like the schmatic I have of the controler.

John if you want I can email the schematics I have of the controler. I
have no idea of how I would do it in ASCI.

Thanks,
Darel

8. ### Rikard BosnjakovicGuest

--
Rikard Bosnjakovic http://bos.hack.org/cv/

Anyone sending unwanted advertising e-mail to my address will be
charged \$250 for network traffic and computing time. By extracting
address from this message or its header, you agree to these terms.

9. ### John FieldsGuest

---
If you're going to make some money from this project and you need help
to complete it and you want me to help you, I'll be more than happy to
email you schematics, bills of material, etc, (for a fee, of course)
but if you're looking for free help and you want to keep the
discussion in this group, (seb) it would certainly be a good idea for
you to post the schematic you mentioned, in its entirety, to abse.
That way we can all have a look at what it is you think you want to do
and comment on it.

Thank you!!!!!!

No I will not be making any money on this project, it is for my
personal use.

This may not be the forum to ask this in but if I post the full
schematic do I need to get permission from the manufacturer? Would you
want the full schematic or just the items we have been discussing?

I am new to both electronics (less then 7 or 8 months) and the Usenet;
this is only the second topic I have posted to. I don't mean to
offend.

12. ### John FieldsGuest

---
You weren't being offensive, I was being grouchy. Sorry about that.
I don't know what the deal would be if you emailed the schematic to
the NG, but if you email me a copy that would be considered "fair
use" and wouldn't be an infringement. You may as well go ahead and
email me the whole thing just in case something comes up later.

Also, I'll need to know how much current the camera inputs need to
draw when they're being exercised.