Rigging a remote mute button...signal?

[brick]

Here's a good one for you guys. I replaced the stock deck in the Accord with an aftermarket head unit, which means that I no longer have use for the audio controls on the steering wheel. As I was driving today it suddenly dawned on me how great it would be if I could use one of the buttons to mute the V1! Here's the thing: I have no idea how I would wire it.

Does anybody know how the mute button on the remote display communicates with the V1? Is it as simple as making the voltage go high on one of the wires? Or is it something more obnoxious like a pulse train? I could always hack the remote display itself but I was hoping I can avoid it.

[crazyVOLVOrob]

Jimbonzz would be the erson to contact since he has the computer software interface he knows how it works

[jimbonzzz]

Actually the voltage gets pulled low on one of the wires. Here's how it should be done:



Jim

[laserblaster]

there is a thing on 911 p car about a remote display which is installed in the rev counter and has a seperate mute button!

also the guy has put switches on the remote wire so that he can turn on and off the remote display, when he turns it off the v1 display comes on!

he has also put a off switch incase he has to turn the v1 off like when your pulled over !

loads of pics and wiring diagrams etc...... you just run 2 wires from the mute button on the v1 remote to your steering wheel stereo controls!

very smart install! i hope this helps





http://p-car.com/diy/v1/remote/index.html

http://p-car.com/diy/v1/

[erobinson]

Actually the voltage gets pulled low on one of the wires. Here's how it should be done:



Jim

Shouldn't the resistor go on the other side of the switch, rather than to ground? It would seem that by making the connection, all that would be accomplished is a straight 12+V to the detector mute pin, and a resistor hanging off of ground. I think you need it before the switch or on the positive side of the switch to be a proper voltage divider.

[brick]

Thanks Jim! That's exactly what I needed to know. The way they have it wired should make it much easier than I thought.

If I'm reading this correctly it shouldn't matter what side of the switch the resistor is on. If you look at the circuit as if it were closed, all you have is a connection between the mute wire and ground with a big resistor somewhere between the two in order to keep current low. That "T" is just a momentary switch.

[jimbonzzz]

Thanks Jim! That's exactly what I needed to know. The way they have it wired should make it much easier than I thought.

If I'm reading this correctly it shouldn't matter what side of the switch the resistor is on. If you look at the circuit as if it were closed, all you have is a connection between the mute wire and ground with a big resistor somewhere between the two in order to keep current low. That "T" is just a momentary switch.

Yep, it doesn't matter which side of the switch the resistor is on. In fact, technically it would still work without the resistor, and some other DIY plans on the internet actually leave it out. However, the actual V1 mute circuit in the remote display contains the resistor, so it is my opinion that it should be used...

Jim

[erobinson]

Thanks Jim! That's exactly what I needed to know. The way they have it wired should make it much easier than I thought.

If I'm reading this correctly it shouldn't matter what side of the switch the resistor is on. If you look at the circuit as if it were closed, all you have is a connection between the mute wire and ground with a big resistor somewhere between the two in order to keep current low. That "T" is just a momentary switch.

Yep, it doesn't matter which side of the switch the resistor is on. In fact, technically it would still work without the resistor, and some other DIY plans on the internet actually leave it out. However, the actual V1 mute circuit in the remote display contains the resistor, so it is my opinion that it should be used...

Jim

Does it contain just one resistor? It seems like they probably would have it set up as a voltage divider since there would be no good reason to run the full 12 volts as a mute trigger, but it's possible. I haven't seen a switch drawn that way in a schematic before, but it looks like the resistor is doing nothing like it is now. If you had one prior to the switch and one prior to ground of equal value, then you'd receive 6 volts at the mute pin for instance. But, you probably already know about voltage dividers and I'm just blabbering:

Of course, someone with a remote display could just take a multimeter to it and press the mute button and see what the voltage is.

[zPilott]

I think inside the V1 is is just looking for current to flow, and it doesn't take much. IIRC a 47k resistor worked as well. I think it is just hooked up to an input pin on the microcontroller.

[jimbonzzz]

Thanks Jim! That's exactly what I needed to know. The way they have it wired should make it much easier than I thought.

If I'm reading this correctly it shouldn't matter what side of the switch the resistor is on. If you look at the circuit as if it were closed, all you have is a connection between the mute wire and ground with a big resistor somewhere between the two in order to keep current low. That "T" is just a momentary switch.

Yep, it doesn't matter which side of the switch the resistor is on. In fact, technically it would still work without the resistor, and some other DIY plans on the internet actually leave it out. However, the actual V1 mute circuit in the remote display contains the resistor, so it is my opinion that it should be used...

Jim

Does it contain just one resistor? It seems like they probably would have it set up as a voltage divider since there would be no good reason to run the full 12 volts as a mute trigger, but it's possible. I haven't seen a switch drawn that way in a schematic before, but it looks like the resistor is doing nothing like it is now. If you had one prior to the switch and one prior to ground of equal value, then you'd receive 6 volts at the mute pin for instance. But, you probably already know about voltage dividers and I'm just blabbering:
Of course, someone with a remote display could just take a multimeter to it and press the mute button and see what the voltage is.

You seem to be VERY confused for some reason.
There is no 12V involved here, and the circuit does not actually apply voltage to any pin on the RJ-11 at all.
The pin is normally high (5V CMOS level if I remember right, or 3V). The momentary switch pulls the mute pin on the RJ-11 low (to ground). The resistor is used as a current limiter.
That's all there is to it.

Jim