I am a complete novice when it comes to the Arduino but I do have an electronics background. On to my project... I have a Pontiac Grand Prix with steering wheel mounted radio controls and this past Christmas I was given an iPod touch. Now I want to mate the two together. The steering wheel controls are a resistance based input circuit that feeds into the back of the radio. Apologies for the bad image, I can upload a better one this evening.
I'm not exactly sure what would be sent to the radio but I'm assuming it detects a voltage level based on which circuit is completed by the series resistors.
Does the Arduino have a built in method to detect something like this or would I need a go between to interpret the voltage level and then feed that as serial data to the Arduino? I found some similar requests around but not the complete info I was looking for.
I basically want to pull out just the next and previous track button pushes which I know I'll need to then send out of the Arduino as serial communication to the iPod. For now I just want to see if I can get the input to work before wasting my time on the output.
And use the T1 of the car wiring to the arduino analog pin, but you will need to change the voltage to the buttons, from 12v to 5 volt, or maybe add a resistor to between T1 and the arduino analog pin, so you dont get a voltage thats to high for the arduino to handle.
or maybe add a resistor to between T1 and the arduino analog pin, so you dont get a voltage thats to high for the arduino to handle.
Shouldn't that be "a resistor between T1 and ground, to act as a voltage divider to bring the voltage down to a 5V level for the Arduino"?
You could also supply the voltage from that battery (if it is the 12V car battery, for instance) to the AREF pin on the Arduino, I think - see here for an explanation:
It might be easier to supply the 5V to the circuit (what is B1, btw - is it the car's battery, or is it a separate battery in the controller on the steering wheel?), as you noted...
I guess my next steps should be figuring out what the radio supply voltage is (I assume ~12 volts) and then using a meter at the other end of the radio input to see what the max voltage going into the unit is when each button is pressed. Actually, I guess I just need to know the voltage when the volume up button is pressed since every other button will be a lesser voltage? It looks like the input is tied to chassis ground through a resistor? I guess depending on what the resistor is that's tied to ground internal to the radio I may see smaller voltages on the dark blue (D-BU) wire feeding the radio?
This is going to be a fun project...
Integrate steering wheel controls with Arduino
Get Arduino to talk serial to iPod when steering wheel controls are pressed
Power arduino and ipod charging from 12 volt source