Steering Wheel Controls - Page 9

Micv · 07-19-2005, 01:29 PM

Have anyone figured out how to calculate which resistors to use.
I have 6 buttons:
Vol - 54 Ohm
Vol + 147 Ohm
Mode 1036 Ohm
Mute 2007 Ohm
Preset 562 Ohm
^ 300 Ohm
No buttons pushed 5kohm <-- Is this normal

Curiosity · 07-20-2005, 08:23 AM

I don't think you need any resistor because of that 5k. Try just connecting it to Vcc and the X axis and see of you get different values for each button.

Jarrod · 01-19-2006, 07:59 PM

Has anyone managed to get this working with a USB port?

I have attached the wiring diagram for my car, and I have physically tested the resistance and it matches the wiring diagram attached to this post. As you can see, I only have two wires for 6 buttons.

Would it be possible to connect this up to a USB gamepad that has an analog controller? I dont have a gameport on my motherboard, and no header for it either, and I dont want to add a PCI card JUST for a gameport. USB would be perfect as I already have a USB hub up front that I could plug directly into.

Otherwise, I was thinking of ordering the Velleman K8055 kit which has two analog inputs. How would I connect this up to the K8055? I'd imagine I need to run some voltage through it somehow...

Curiosity · 01-20-2006, 12:07 AM

With a normal ADC like the K8055 it's pretty simple and more stable than a gamepad. I've used both. All you need to do is connect 1 wire to 5V off the device (I'm sure it's there) and the other wire to the analog input. If it jumps around with no buttons pressed, just put a 100K resistor between the input and ground. That's all you need.

scfountain · 01-21-2006, 01:31 AM

If anyone wants a much easier solution to steering wheel mounted controls, i.e. you already have steering wheel controls and want to hook them to your carputer, check out http://www.xkeys.com/custom/xkmatrix.php. There are 2 versions, one is USB, the other is PS/2. The USB can't store multimedia commands, such as volume +/- or track forward/back, according the the tech rep. But the PS/2 one can. And instead of having to write a program or code, you can simply plug a keyboard into it, and the device will learn the keystrokes from the keyboard. Much easier in my book. Costs around $59.

Jarrod · 01-22-2006, 02:07 AM

The XKeys solution wont work for most people as most steering wheel controls only have 2 o 3 wires for 6 or so buttons. The board needs an analog input, such as the K8055.

Thanks for the input Curiosity. I think I will just get the K8055 as it would allow me to do much more with its extra inputs and outputs.

civic5zigen · 02-28-2006, 12:58 AM

I give up on the usb gamepad, can the K8055 work with G35 steering wheel which is providing negative? Do I just tap into my existing wire since I want it to control my stock headunit as well.

Curiosity · 02-28-2006, 12:03 PM

Check the voltage with and without each button pressed. I think it's in the 0~12v range, so you'll need a resistor divider which is really easy, and the HU should still work fine.

civic5zigen · 03-01-2006, 02:45 AM

The range is 0~5v, based on the output below what kind of resistor divider do I need? Also, notice the 25(y) wire is acutally a remote control ground instead of +5v or +12v, would it work in this case? Because I plan to use K8055 as trigger for my reverse camera as well where I'll connect to my reverse lamp. When in reverse, it should send singal to RR to bring up the camera skin. I am a nood when it comes to electronic, but seeing my SWC is providing negative and the reverse lamp is pumping positive so I am not sure rather both can work with one K8055 device?

Curiosity · 03-01-2006, 05:25 AM

I wonder where it gets the power from? It's already set up for a 5v input so you can just connect 22 and 23 directly to a couple anolog inputs without any additional parts. Connecting to a joystick X and Y should have worked as well, though.

ITL · 03-01-2006, 08:29 AM

Does a joystick work the same way that this one-wire method for the steering wheel does? Just by changing the resistance on the line?

Curiosity · 03-01-2006, 11:28 AM

Yes. It's just resistors producing different voltages. A joystick uses a potentiometer that's connected to ground and 5V so it can produce the full voltage range inbetween that. The ADC then converts that voltage to a value representing the position of the pot. When you calibrate it, it will assume the center is the voltage when it's calibrating, which should be 2.5V but in this case it would be 5.0V. Normally 2.5 = 0, 0.0 = 127 and 5.0 = -128, but with this it should be 5.0 = 0, 1.7 = 100, 0.0 = 128 or somewhere around that.

ITL · 03-01-2006, 12:13 PM

excellent, thanks. Correct me if I'm wrong: I could find the one wire from the steering harness that carries this voltage and "listen in" on it to determine what has been pressed on the steering wheel- based on measuring the voltage. How would one physically tap this line without introducing any interference or further resistance?

Curiosity · 03-01-2006, 06:41 PM

With a K8055 or some PIC, you could connect it direct. There's very little current draw. For a joystick there may be though. A 500 ohm resistor in series with each one should be sufficient.

civic5zigen · 03-02-2006, 03:11 AM

basically 22 and 23 is providing ground rather then positive voltage as I understand it. So u think I can just tapped into 22 and 23 and connect to the K8055?

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