Arduino car audio remote control

Hi,

New to Arduino and electrical circuitry in general. I want to design a remote control for my car's radio which can be hard-wired. I have found a tutorial which describes how to send the different commands by changing the resistance on the line. Can an Arduino be used to simulate this resistance changes without the need for multiple resistors and switches? Below is a circuit design which has multiple switches with resistors of differing resistance each one controlling a different function of the radio. Any help or suggestions would be appreciated.

http://www.jvde.net/pioneer_wired_remote/pioneer_wired_remote.htm

So you just need to send different voltages to the radio? One way would be to use an external Digital to Analog Converter, maybe with an op-amp buffer. As it's a remote, do you plan to have one arduino send characters to a second arduino that will control the DAC (or whatever) to create the voltage to the radio? Or a wired connection, or ...

I have a car with steering wheel controls which I need to convert from their native signals of differing voltages into the native signals of the radio. I was thinking of maybe using a digital POT to change the resistance in the line depending on the command that needs to be transmitted. I would like to explore down the line creating a remote with another anduino but for now all I want is to convert the car’s signals to ones that the radio understands.

My understanding of the DAC is limited but I understand that I would send a signal to it from the andruino which would be converted into a specified volatage in the line.

That seems pretty straightforward. Take a voltage reading when a button is pressed, and send the voltage that you want for that function. You can use a DAC with serial interface - you send it a number with I2C, SPI, Shiftout, etc and it outputs a corresponding voltage. You can search for DAC shields that can do this, or wire up your own DAC.

Awesome sounds like the way to go. I'll look into that thanks for your help!