VW Radio Remote Control library for arduino

Moved from this repo (https://github.com/tomaskovacik/arduino/tree/master/VW_radio_remote_control) to separate repository when it became library.

later I realized that this protocol is inverted standard NEC IR remote protocol with 16bit address

https://www.sbprojects.net/knowledge/ir/nec.php

this library should also works, but I did not test it, do not forget you need invert it (standard NEC start with 9ms HIGH pulse followed with 4.5ms low pulse, while VAG start with 9ms low folowed by 4.5ms high etc ...)

also NEC protocol use LSB first while my implementation use MSF first, maybe I will change it in future

Instalation of library

Refer to oficial arduino guide here: https://www.arduino.cc/en/Guide/Libraries Download content of repository and extract it into arduinoSketchFolder/library directory.

How to use it

Example directory has 5 examples, take a look at them.

sketch must start with

#include "VAGRadioRemote.h"

define arduino pin which will be connected to "REM" pin of radio and/or pin for input from remote control to read pressed button input pin must have hardware input capability

#define REMOTEOUT 2
#define REMOTEIN 3

then initialize library with this line:

VAGRadioRemote remote(REMOTEOUT); //only output
VAGRadioRemote remote(REMOTEOUT,-1); //only output
VAGRadioRemote remote(REMOTEOUT,REMOTEIN);  //for both input and output
VAGRadioRemote remote(-1,REMOTEIN);  //only input

in setup() function include this line for set pin as output:

remote.begin();

and in loop() this functions can be used:

void send(uint8_t _byte); //this send command "_byte" to radio
void up(); //send predefined code for UP button
void down(); //send predefined code for DOWN button
void left(); //send predefined code for LEFT button
void right(); //send predefined code for RIGHT button
void volumeUp(); //send predefined code for VOLUME UP  button
void volumeDown(); //send predefined code for VOLUME DOWN button
void button(uint8_t buttonNumber); //send predefined code for button defined as "buttonNumber" = 1,2,3,4,5,6.... (memory,cd buttons on front panel of radio)
void reg(); //send predefined code for REG button - switch between regional and DX radio erceiving mode
void am(); //send predefined code for AM button
void as(); //send predefined code for AS button
void fm(); //send predefined code for FM button
void random(); //send predefined code for RD button (random)
//void down_custom(uint8_t _custom_down); //send predefined code for volume button with increment of "_custom_down, probably custom_up exists ... 
void tp(); //send predefined code for TP button
void scan(); //send predefined code for SCAN button
void mode(); //send predefined code for MODE button
uint8_t gotNewCode(); //return true if we have new code read from input
uint8_t newCode(); //return new code
void clearGotNewCode(); //clear flag that we have new code red
String decodeRemote(uint8_t code); //get meaning of code in human readable format
String decodeRemote(); //get meaning of newCode in human readable format

Examples

Library includes 5 examples, code_finder and emulator are using ebay LCD shield(2x16) with 5 buttons on A0. Examples use pin 2 of arduino as output to radio (remote signal REM).

• code_finder is sketchup for finding all codes understended by my audi concert/chorus 1 radios
• emulator is sketchup emulating audi MFSW
• Radio_remote_over_serial - serial to remote control protocol example
• Radio_remote_read_and_write - read remote control and send it to another pin of arduino
• Radio_remote_read_to_serial - read remote control and write to serial what button was pressed in human readable form

More info: http://kovo-blog.blogspot.sk/2013/10/remote-control-audi-radio.html

Protocol

On vehicles where the radio does not use CAN bus, the MFSW (Multifunction Steering Wheel) controller talks to the radio using only 1 wire, which is called REM (remote).

REM line is 5V logic, idle state is HIGH (5V)

• start bit: 9ms LOW 4.55ms HIGH
• logic 1: ~600us LOW ~1700us HIGH
• logic 0: ~600us LOW ~600us HIGH
• stop bit: ~600us LOW

The MFSW controller always sends a packet of 4 bytes to the radio. It consists of 2 unknown header bytes, followed by a code byte, and finally a checksum byte:

0x41 0xE8 <code> <checksum>

The checksum is 0xFF - code. Example:

0x41 0xE8 0xD0 0x2F

Code byte: 0xD0, Checksum: 0xFF - 0xD0 = 0x2F.

MFSW

Using a logic analyzer, these codes were captured from an MFSW without telephone option:

Steering Wheel Button	Code	Complete Packet
UP	0xD0	0x41 0xE8 0xD0 0x2F
DOWN	0x50	0x41 0xE8 0x50 0xAF
LEFT	0x40	0x41 0xE8 0x40 0xBF
RIGHT	0xC0	0x41 0xE8 0xC0 0x3F
VOL+	0x80	0x41 0xE8 0x80 0x7F
VOL-	0x00	0x41 0xE8 0x00 0xFF

Audi Concert I Radio

Using the code_finder program above, an Audi Concert I radio responded to these codes:

Code	Function
0x00	Volume down
0x01	mem/cd1
0x03	mem/cd3
0x05	mem/cd5
0x07	search up
0x09	reg on/off
0x0B	tp
0x11	AM
0x15	AS-STORE
0x17	FM
0x1D	search down
0x20	AM->AM+AS->FM1->FM2->FM1+AS->FM2->AS/in CD mode “RD”
0x22	AM->AM+AS->FM1->FM2->FM1+AS->FM2->AS/in CD mode “RD”
0x24	AM->AM+AS->FM1->FM2->FM1+AS->FM2->AS/in CD mode “RD”
0x26	AM->AM+AS->FM1->FM2->FM1+AS->FM2->AS/in CD mode “RD”
0x27	MEM 1->2->3->4->-5->6
0x29	TP
0x2B	search up
0x3C	seek up
0x40	LEFT FM1 6-5-4-3-2-1-FM2 6-5-4-3-2-1
0x42	LEFT FM1 6-5-4-3-2-1-FM2 6-5-4-3-2-1
0x44	LEFT FM1 6-5-4-3-2-1-FM2 6-5-4-3-2-1
0x46	LEFT FM1 6-5-4-3-2-1-FM2 6-5-4-3-2-1
0x50	Seek down/FR
0x52	Seek down/FR
0x54	Seek down/FR
0x56	Seek down/FR
0x60	Seek down/FR
0x62	seek down
0x64	seek down
0x80	Volume up
0x81	Volume up
0x82	Volume up
0x83	Volume up
0x84	Volume up
0x85	Volume up
0x86	Volume up
0x89	-2 Volume down bas/treble down/fade rear/bal left
0x8B	-4 Volume down bas/treble down/fade rear/bal left
0x8D	-6 Volume down bas/treble down/fade rear/bal left
0x8F	-8 Volume down/fade rear/bal left
0x97	TP
0x9B	SCAN
0xA0	MODE
0xA2	MODE
0xA4	MODE
0xA6	MODE
0xC0	RIGHT FM1 6-5-4-3-2-1-FM2 6-5-4-3-2-1
0xC2	RIGHT FM1 6-5-4-3-2-1-FM2 6-5-4-3-2-1
0xC4	RIGHT FM1 6-5-4-3-2-1-FM2 6-5-4-3-2-1
0xC6	RIGHT FM1 6-5-4-3-2-1-FM2 6-5-4-3-2-1
0xD0	Seek up/FF
0xD2	Seek up/FF
0xD4	Seek up/FF
0xD6	Seek up/FF
0xE0	seek up
0xE2	seek up
0xE4	seek up
0xE6	seek up