Electronics Wiring up a remote control & controlling it by PC replay board

Hello all, I have a project that I want to start on for my Media Center. I have assembled a PC Relay board that has 8 relay controllers on it. Each controller is switched on and off from the printer port.

Each relay is rated at 15a/24vdc. They are the Goodsky RWH-SH-1120 model. Each relay has three outputs attached to it, [NC][C][NO].

Relay PDF

Now with all that said, is it possible to use my A/V Receiver remote to turn on the receiver using the pc relay board? If possible, how would I hook it up to act like I am pushing the button on the remote? I know when pushing the button it acts as a "ground" that joins the two traces together to trigger whatever the button does.

I'm sure I wouldn’t use the 12v line to send to the remote since that would probably fry everything. Do I need to use the ground to trigger the button traces?

Also, each remote takes 2 AA batteries. Do I need to use a resister from the 5v on the computer line to the remote (so that I don’t have to use the batteries) so that it won’t fry as well?

Thanks for your time,
David

 

For the remote's power supply, use a 3.3V regulator if you can get one, or a LM317 or similar adjustable regulator, set for about 3V, instead.

 

erm if its an infra-red remote, then surely the easyest thing to do would be to use a infrared emitting diode hooked upto your PC.

 

if you want to use the relay, you would probably have to take apart the remote, find the solder pads under the button(s) you want, and solder them to the relay. you would also (As mentioned here) need a 3v power supply (assuming 2x AA batts). if you have 12v, a 2k and 6k resistor bridge can get you 3.0v

if you have a relay card, assuming that the media PC is close to the receiver, you would probably be able to hook into the power button in the receiver easier the using the remote.

if you get a IR LED, you can hook it up to your serial port.

or if you have an extra line out (example: if you had integrated audio and replaced it with a SoundBlaster) you can record the remote's signal as a .wav, and play it back through the spare output to a IR LED. as long as your system samples at 44khz, this will work (IR is at 40hkz). if your receiver has a IR-IN 1/8" jack, you can hook this directly to the line out, with no additional components.

 

Doesn't Girder support this type of control? Unless I'm misunderstanding what you are trying to do, the way I see it is that you have 8 relays attached to your parallel port and want to know if you can control those relays with your A/V remote...?

 

Thanks for all the replys.

theshadow27 is pretty much the closest one to what i want to be doing.

I do have 8 relays attached to my port. But i want each relay to do the same job as you pushing a button on the remote. I am making a LCD 7" screen and a touch-screen overlay for it so that i can use that as a Media Center Remote. It will look much cooler than a regular remote becuase i will be able to customize it with graphics and such. I have included a pic of my menu as is right now.


theshadow27: I have taken apart the remote. All i see are traces for the many buttons that are on it. Which one, [NC][C][NO], do i use to hook them both up on the remote? I have tryed to take a pic of the boards layout but its fuzzy, but maybe you can make out what im talking about.


theshadow27: If i take the 5v for the red wire on the computer, what resisters do i need to put it down to 3v? You gave me an example of 12v to 3v.. but i need 5v to 3v which im sure is a lot more easier than trying to use 12v?

David

 

dude, just use an IR doide, will save yourself a lot of hassell.

as he said you can use the serial port for this (status lines, as you can't use the serial port because it dosen't do the right modulated carryer) but by far the easyest way is the sound card, now myself i'd put an op-amp for isolation there, but fundamentally all you need is a modulated decoder to understand the IR in the first place, then record it in via the sound card. The problem is you then need to re-modulate the signal (the decoder demodulates it, its an AM signal in effect), you can either do this in software (don't know of a program that does that) or you can do it in hardware fiarly easily.

 

TheAnimus: No disrespect or anything but you way sounds like it would be a lot harder than me just wiring to traces together for the pc relay to turn on for a second and act as if I pushed the button. And way do you use a sound card as an example?

All I really need to know is what wire I need to use to connect the 2 traces for the “ON” button, “Volume UP” button, “Volume DOWN” button and the “Mute” button. Each one of those will take up a replay on the board. I just don’t want to hook it up wrong and blow something up because a replacement remote is expensive!

Again, theshadow27 had the right idea about soldering the button(s) to the replay.

Hope this clears things up,
David

 

okay, well what you want to do is solder surfice mount style onto the S shapes, both sides to each contact of the relay. you might find problems with bounce of the relay. Also you will find the solder will easily fall off (i'd recomend glue over the top, once u know they work. glue gun globby style glue works a treat)

i still say the one IR emmiting diode approche is easyer, there are plenty of other things to use your relay board for.

as for bounce it *shouldn't* be a problem because the button will have its own de-bouncing solution, which you should be able to use, its just sometimes high voltage relays make a lot for a low voltage signal.

 

That looks really cool, just don’t try and run it off a battery

Which ever way you feel comfortable with is the way i will explain. after it, it is your project.

One note, however, every time you click a button you are going to hear the relay card click, YMMV, but it would piss me off. The optocoupler -> IR LED would be completely silent. Just something to think about

I heard my name...

You will have to figure out which buttons correspond to which traces. I would guess, but it would be pointless, and I assume you still have the buttons anyway. So this goes for all 3 button/relay combos:

Here is the math. V=I/R, so to get the exact value for a resistor in series with the remote would require knowledge of its current draw, but for our intents and purposes, we can guess its around 15ma. So…

V = I / R
3 = .015 / R
3 R = .015
R = .015 / 3
R = 200 Ohms

So a 200 ohm resistor in series (inline) at 5v will produce a 2 volt drop. The closest common resistor value is 220, or you could put two 100 ohm resistors together, (also in series) to get 200 ohms. If you want, try a 330 ohm resistor and see if you get the range that you need, otherwise, go to the 220.

An alternative technique is to use a few diodes for the voltage drop. Each 1n914 (standard silicon diode) that you add in series will drop .6 volts off V+ due to a characteristic called “forward voltage”. So if you add 3 diodes to your +5v you will get about 3.2 volts, which will probably be close enough for your remote to not fry.

Good luck, and let me know if you need any more help

 

Well gee, at the same time when u posted your message i finsihed up my high-tech drawing of what to do with the wires... But it seems that u have already answered my question in your last post!

Anyways, since i spent some time on the drawing ill just post it to make me feel better



David

 

The final blueprint, Tell me if i am doing it wrong... or somthing is wired wrong.

Thanks again!



David

 

looks good to me
let me know if it doesnt work

 

Theanimus - You're forgetting that just about every soundcard has a filter to remove anything above ~21 or 22 KHz. Otherwise you would get wierd harmonics if you were recording audio. Also, a soundcard has a lot of signal conditioning. etc...

Essentially, stay away from the sound card if you want to do stuff with digital.

ALso, debouncing IS an issue, bacuse the little-carbon-coated-rubber-pad type-switches (like in every remote) don't have any bounce. I can confirm that because i have done something similar and had bounce issues.


Essentially, you get bounce when two hard metal contacts connect, but as one of the contacts in the "s type pad switches" is rubber, it compresses rather than rebounding.

 

I generally dislike using resistors for voltage drops in circuits like that. LED's are a different story, the voltage drop across them is constant, so the I-R relationship is a given.

In this case, the voltage supplied will be higher when the remote isn't doing anything, and will drop off when the LED is transmitting, as that will take much more current than the IC.

 

gOth: So what do you suggest for the 5v to 3v?

David

 

either an adustable voltage regulator or a 3v zenier diode

 

yeh most CIR (Consumer Infra-Red) is done at 38khz to 42khz. Thats the carryer, a single package detector + demodulator will of course output something much less than that, as it must be well below the carryer.

now as for outputting the signal, your probably write, but if you can get 44khz out of the sound card, without been filtered that would be enough.

Otherwise you'd need your own integrator.

As for bounce, i had a fealing that might be the case, because most membrains are ment to help reduce some bounce.

Might it not be easyer to use some driver chips and wire the remote striaght upto the LPT, no relay clicking sound, much cheaper.

 

Well i answered that question in my first post, but as theshadow27 said, a 3.3V Zener would be a good choice too.

 

Okay. If you want to replace the relay card, check out the MAX4522 for an analogue IC switch chip that runs off 5v, with no bounce.

IMHO, the resistor would work just fine. Adding a second resistor to make a voltage divider would probably make it work better. But since “g0th” disagrees, here are some more options explained in detail.


First, a LM317 with R1=100 ohms and R2= 140 ohms will output 3 volts, up to 500ma.


The next option is using 3 diodes to drop ~.7v each, giving you about 3volts. As long as you don’t hook anything besides the remote up, you should be able to use any diodes you have lying around. To learn more about diodes, check out this


The third option is a zener diode. You would select a 3.3v zener with a 50 ohm resistor. This will give you ~50ma leeway at 3.3 volts. More information can be found here