Using a parallel port to control a remote control...

Hi!

I am wondering if this will work, and dont want to destroy anything trying,,,

i know theres products out there that do this, but I want to make my own...

Through software I can control turning on individual pins out my parallel port.. The switch on my remote basically just closes the circuit for that particular button.. I want to know if the voltage going through the remotes button when closed (5v) matches the voltage comming out of my parallel port (which it does), is there a way I can wire in my parallel port to activate the button through software?

So one end of the switch has 5v, and the other has nothing until the switch is pressed.. Can I just wire in the data line of my parallel port to the end of the switch that is doing nothing. Then when I turn on that data line +5 will go and the remote will think the button was pressed and act accordingly?>

Do I need to tie the ground out the parallel port to the ground on the controller?

thanks for your help

Reply to
flagon500
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Thanks for your reply.. the C64 is awesome.. still have one.. anyways...

I am still a bit confused.. I write software and havent dabbled into the hardware aspect very much..

Can I just take say, d0 (the first data pin on the parallel port) and run it directly to the controller? Just 1 wire? or do I have to run the ground wire as well?

Thanks for your help.. Like I said I am just getting started in this hardware stuff,,,

I also am not really that concerned if I blow up my xbox controller/computer/house.. but i would like to know if I am doing something completely wrong...,

Reply to
flagon500

you have to have atleast two wires carry a signal.

CMOS

Reply to
manusha

it actually is 5v.. i am using it to control my xbox via wireless xbox controller.. I tore it apart and verified it is 5v... Just trying to simulate digital button presses on it.. Dont need to bother with the analog buttons on the controller...You are correct the switch is using one of those conductive rubber pills...

thanks for all the help

Reply to
flagon500

voltage

can

turn

was

the

One of my first projects in the old days was to use a couple of CD4051s tied to the keyboard matrix of a shortwave radio. A Commodore

64 drove them. I suppose you could use a similar scheme if your remote keys are scanned.... >
Reply to
Rick

No, it's not that simple.

The keypad on your remote consists of a 'crosspoint' switch arrangement where there are X by Y lines to minimise the number of connections needed to provide a total of up to X times Y buttons.

Each switch button is an isolated switch ( normally a conductive rubber 'pill' ).

Also, remotes don't work on 5V, typically around 3V from a couple of AA or AAA cells ( more like 2.5V and less as the batteries reach end of life ).

Whilst it would be possible to provide an interface from a parallel port, I wonder if you really fancy going to all the trouble.

What's the application ?

Graham

Reply to
Pooh Bear

Consider using optocouplers. Drive the LED part from the parallel port (use a resistor) and have the transistor 'press' the button.

If you can't be bothered to measure the polarity, just try it both ways.

Regards,

Iwo

Reply to
Iwo Mergler

xbox

to

using

As others have pointed out, the keyboard is a switch matrix. The matrix is scanned by a processor to detect a switch closure. Review anything you can find on "how a keyboard works" and you will see why just putting a voltage on one line won't work.

The hardware requirements were quite minimal in my little project-you should be able to figure something out. If I still have any drawings around I'll email them to you....

Reply to
Rick

It's probably worse than that - the keys are probably on a matrix, that the uP in the remote scans. Just DC won't work.

You could buzz it out, and put a transistor in place of each button at the intersection of a row and column line, and turn on the transistor with the port, and yes, in this case, you would connect the grounds together. But to really do this properly you need a scope (so you know which xsistor lead to connect to which line), and probably some experience with scanned switch matrices.

Good Luck! Rich

Reply to
Rich Grise

wireless

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operated

Well, to be honest, I don't even know what an xbox is, lol...

And I did use bilaterals, by the way...

Reply to
Rick

calculator,

by

Gosh, that reminded me of a thing I made way back when to display the finishing order of 4 Pinewood derby cars. It used a calculator with about a billion ICs for timing, latching, sensing, etc. Boards stacked on top of each other, crammed into a box with the calculator mounted on top..

Almost laughable looking back at it !.

Reply to
Rick

And how do you *know* it's a matrix? What I mean is: I have designed a remote control for Garmin GPS's which only required 8 keys. Since I used a micro that had 16 I/O pins, it was quite pointless to make a matrix. It was much easier to give each switch it's own input.

If it is not a matrix, a simple NPN transistor between the switch and ground (that is, *if* they switch to ground) will do. Drive the base through a 10k resistor from the LPT port. And connect the ground of the LPT port to the ground of the remote. If it is a matrix, use bilateral switches like the

4066. Powered from the remote's supply, such a switch can be operated 'floating' on a matrix point.

Meindert

Reply to
Meindert Sprang

:-). It's MicroShafts counterpart of the Playstation 2...

I used them decades ago to drive the keys of my TI programmable calculator, to load programs and to convert cheap $10 calculators into counters by driving the '=' key. You had to type '1+' first to get it going :-)

Meindert

Reply to
Meindert Sprang

I did some tinkering some time back with an IR remote control to control it via my computer. You can do what you want to do via the parallel port with out too much trouble. The remote I tinkered on (below) had the buttons in a 5x7 matrix. I did some testing, and this remote can be controlled via the parallel port using two 74HCT259 chips (in multiplex mode) connected to the parallel port, 12 5k resistors on the chip output lines (5 on one chip and 7 on the other), connected to 12 NPN transistors (7 in one bank and 5 in the other), 5 diodes on the 5 transistor bank (to prevent back feed), and 12 wires connected to the remote chip and to the 12 transistors, You will need to sort out the pins on the IR chip with a "beep" continuity multimeter to figure out the wire/button maxtrix. The transistors, resistors, and diodes could probably be replaced with two 4066 switch chips (I haven't tried those yet). Down the road if I get the time I'll wire one up and put the schematic on my web page. Somewhere on the net there is a schematic of a Radio Shack IR remote control that shows the typical button matirix. My remote has 33 buttons (out of 7x5=35) on it. All can be controlled using this type of setup.

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Reply to
Si Ballenger

Why not leave the remote intact and build a little emulator that you control from the parallel (or, probably easier, the serial port)? That is, determine what the output of the remote is for a given keypress and program that sequence into a microcontroller. Tickle the uC to drive an IR LED for the function that you want.

You'll need an IR receiver module (e.g., Radio Shack 276-640) to demodulate the transmitted signal from the remote and determine the sequence for each key. That particular one is 38 KHz center freq but will probably respond to a sufficiently strong source that's a couple of KHz off. Digikey (and others) carries modules with other common bandpass freqs; search for "RECEIVER IR REM CTRL".

There are also several web sites that have IR remote info, including common device codes for different manufacturers.

--
Rich Webb   Norfolk, VA
Reply to
Rich Webb

OK. You could use a load of CD4016 or 4066 analog switches across each pair of switch contacts. You get 4 switches per package. You can power the

4016s off the remote's 5V supply and 4016 inputs will turn the individual switches on and off.

The parallel port is a bit short of lines to play with though. 8 data plus erk - I forget - several control/handshaking lines too.

Looks like you'll have to do a 'decode' to generate all the individual switch presses. A rom maybe ?

Graham

Reply to
Pooh Bear

xbox

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The C4051 is a 1 of 8 with binary decoding. I used 2 of them....

Reply to
Rick

Yes, of course. If you only need to make one switch contact at a time ( as here ) that'll indeed be a better bet.

Graham

Reply to
Pooh Bear

You've almost certainly got this the wrong way around; closing the switch either closes one loop in a matrix or grounds one pin on a micro, but either way the "open" state is high, not low.

Doing it this way is irksome. Go to

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and you will find a ready-made solution to transmit and receive IR codes from your computer.

Reply to
zwsdotcom

Just as a followup, below is a pdf of the schematic for an IR remote showing the button matrix and how they connect to the chip in the remote. .

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Reply to
Si Ballenger

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