using PIC to act as button push

[[email protected]]

I've got a little device that has some pushbuttons on it, and an LCD
that lights up. The PCB has some room on it, and I want to add a PIC
that I can use to "push" the buttons on this. Once I do that, I'll
have the PIC cycle through button pushes in order to automatically show
the functionality of the device.

Any ideas on how I can do this?

The button traces are a standard two traces that interlock, but do not
touch. The conductive rubber button is pressed, and touches both
traces to complete the circuit.

How can I get the PIC to do that for me?

 

[Donald]

I've got a little device that has some pushbuttons on it, and an LCD
that lights up. The PCB has some room on it, and I want to add a PIC
that I can use to "push" the buttons on this. Once I do that, I'll
have the PIC cycle through button pushes in order to automatically show
the functionality of the device.

Any ideas on how I can do this?

The button traces are a standard two traces that interlock, but do not
touch. The conductive rubber button is pressed, and touches both
traces to complete the circuit.

How can I get the PIC to do that for me?

Easily done.

But a little more information please.

Does one side of each switch go to ground ?

How many buttons are there ?

Is this "little device" publicly available ??

donald

 

[[email protected]]

Cool...

Yes, I think so. One side of each switch is connected to the same
trace which ends up in a place known as Vss. The other side of each
switch goes to a place underneath the epoxy, it would appear each to a
different place. I checked the resistance between the common switch
traces and the negative terminal of the battery clip and there was
virtually no resistance.

There are 3 buttons.

Publicly available, yes, but no schematics or circuit diagrams or
anything like that.

Tx,

George

 

[Dan Hollands]

With the PIC ground and the pcb ground connected you can probably just
connect the output of the PIC to ungrounded trace that goes to the
pushbutton.

--
Dan Hollands
1120 S Creek Dr
Webster NY 14580
585-872-2606
[email protected]
www.QuickScoreRace.com

 

[[email protected]]

I see, so that when the output pin is off, the switch is open (that
means button not pushed, right?), and when the output pin is on, then
that pushes the button? Is that the idea?

Tx,

George

 

[Donald]

I see, so that when the output pin is off, the switch is open (that
means button not pushed, right?), and when the output pin is on, then
that pushes the button? Is that the idea?

Tx,

George

Yes, thats it. But "ON" mean logic LOW and "OFF" means logic HIGH.

So tell us:

Publicly available, yes, but no schematics or circuit diagrams or
anything like that.

What is it ??

donald

 

[[email protected]]

Right... I was wondering if you were going to ask.

I'm practicing on this:

http://www.pedometersusa.com/Pages/Sportline/340.html

And I eventually want to make it work on this:

http://www.streettags.com/Digital_LED_Name_Badge_products_s/2.htm

It sounds easy, I'll give it a shot, and post back tomorrow, let you
all know of my success or failure.

Tx,

George

 

[[email protected]]

You know, now that I'm at it, I just imagined that getting my PIC to
output IR inside an enclosure to the IR input of the 2nd device would
be more of a pain than just manipulating the buttons.

BUT, perhaps in the long run, assembly might be a lot easier, because
there would be no buttons to remove from the PCB. Just connect, glue
and go.

If the level of difficulty of "pushing the buttons" is 1 on a scale of
1 - 10, how hard would it be to rig the IR output? I assumed I would
have to:

1) Decode the output of the original device's IR
2) Replicate that in code of PIC
3) Find the circuitry in some PIC publication and "steal" it so that
the hardware would work
4) Find the proper positioning of the IR output device so that the
communications would work reliably

There's probably more, but I thought those were the major milestones.

What would that difficulty level be? And how hard would it be to find
somebody who could do it?

Tx,

George

 

[Daniel Pitts]

if the level of difficulty of "pushing the buttons" is 1 on a scale of

1 - 10, how hard would it be to rig the IR output?

I don't know the answer, but I do know that usually you start at 5, not
one, in case IR would be easier.

 

[Donald]

http://www.streettags.com/Digital_LED_Name_Badge_products_s/2.htm

It sounds easy, I'll give it a shot, and post back tomorrow, let you
all know of my success or failure.

Tx,

George

OK, now that we know what the target is.

Do you understand that the "ON" state will need to be low for many
milliseconds, and "OFF" for many milliseconds before you "press" the
next button ??

The speed of each key press will be many times slower than the PIC runs.

donald

 

[[email protected]]

Oh Danny-Boy, the pipes, the pipes are callin'

Although I just could not imagine it being so, POINT TAKEN! You are
so right!

Tx,

George

 

[[email protected]]

Yes, I do realize that, I would imagine because of their debouncing
routines, I will need to wait it out...

Still, if that is 50 milliseconds ON to recognize a button press, and
say 50 to establish the OFF, that's 5 chars per second, plus a the 3
second wait, is about 5 seconds to establish and display the messages I
want to display.

I remember from my IBM-PC days that can seem like an eternity.

I will have to get the IR kit and see if those times can be improved
upon.

Tx,

George

 

[Rob]

Yes, thats it. But "ON" mean logic LOW and "OFF" means logic HIGH.

So tell us:


What is it ??

donald

I'm not sure about this, but it may be useful to have on="output low" and
off="pin set as input". That way the buttons can still be used without them
having to forcibly pull the pic out hi level down.
rob

 

[Donald]

You know, now that I'm at it, I just imagined that getting my PIC to
output IR inside an enclosure to the IR input of the 2nd device would
be more of a pain than just manipulating the buttons.

BUT, perhaps in the long run, assembly might be a lot easier, because
there would be no buttons to remove from the PCB. Just connect, glue
and go.

If the level of difficulty of "pushing the buttons" is 1 on a scale of
1 - 10, how hard would it be to rig the IR output? I assumed I would
have to:

1) Decode the output of the original device's IR
2) Replicate that in code of PIC
3) Find the circuitry in some PIC publication and "steal" it so that
the hardware would work
4) Find the proper positioning of the IR output device so that the
communications would work reliably

There's probably more, but I thought those were the major milestones.

What would that difficulty level be? And how hard would it be to find
somebody who could do it?

Tx,

George

So, if I understand this new specification:

The first display will send a command to the slave display,
maybe to sync the displays together.

Or are you thinking of replacing the "PC to IR Programming kit" ??


donald

 

[Donald]

I'm not sure about this, but it may be useful to have on="output low" and
off="pin set as input". That way the buttons can still be used without them
having to forcibly pull the pic out hi level down.
rob

Thanks Rob,

You are correct. That would be a better design.

But he would running the PIC from the same battery as the display. So
it should not really matter.


donald

 

[Don Lancaster]

I've got a little device that has some pushbuttons on it, and an LCD
that lights up. The PCB has some room on it, and I want to add a PIC
that I can use to "push" the buttons on this. Once I do that, I'll
have the PIC cycle through button pushes in order to automatically show
the functionality of the device.

Any ideas on how I can do this?

The button traces are a standard two traces that interlock, but do not
touch. The conductive rubber button is pressed, and touches both
traces to complete the circuit.

How can I get the PIC to do that for me?

4066 quad analog switch

--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com