iPod Speaker Dock Idea

You wouldn't need the Netduino at all.  For the amplifier there are many options, you can pick up an audio amp and follow the guidlines in the data sheet

http://www.newark.com/texas-instruments/lm386m-1-nopb/ic-audio-pwr-amp-class-ab-325mw/dp/41K5099

or if you aren't comfortable with electronics, you can buy a kit

https://www.sparkfun.com/products/9612

for both 2 and 3 you need an ipod breakout

https://www.sparkfun.com/products/8295

Thanks almost exactly what i need, but is this variable? (the amp)

One more question, What could i use to Play/fast forward/skip songs?

That amp has two pots on it to change the left/right channel volume.

Apparently for remote controle, you can use serial commands, so you might have a use for your netduino after all

http://www.adriangame.co.uk/ipod-acc-pro.html

I looked at the schematic for the IC and it has only 1 channel, but has two pot ports should i use two and wire the pot to all four ports using a common lead?

Yeah, not the best IC for stereo sound I think.  Try this one

http://www.newark.com/texas-instruments/tpa122d/amp-stereo-audio-150mw-smd-soic8/dp/26M4256

-note, this one might be a bit small for your speakers.  You might have better luck with that kit for higher power.

If it's the old iPod dock (pre-Lighting) the pinout is readily available.

I believe adapters, docks, etc control the iPod with serial commands (there's an RX TX on that dock)

Here's a good, easy to use audio amp http://www.newark.com/texas-instruments/tpa6021a4n/ic-audio-power-amp-class-ab-2w/dp/43K4150?in_merch=Popular%20Products

Just make a simple amplifier circuit, and just use a pinout to figure out how to connect it use this http://pinouts.ru/PortableDevices/ipod_pinout.shtml for the older connectors for the new one use the pinout on this webpage http://en.wikipedia.org/wiki/Lightning_%28connector%29 this webpage will help you build a amplifier http://www.circuitstoday.com/category/amplifier-circuits

Here is some sample C code to play and skip right/left with the old (pre-lightening) dock connector. I have tested this on the original

iPod touch. It uses the ATmega64, but should be easy to adapt for any processor.

To use it, call ipod_uart_init() at the start of your program, and then use the ipod_tx_cmd() command whenever you wish to

control the iPod, e.g. ipod_tx_cmd(PLAY2) etc..

The '2' is not important, it just means it is a so-called 'type-2' command (the iPod understands some simpler Type-1 commands too, which

I did not implement.

The instructions are in an array which could be extended for other commands if desired.

// Port E

// Ipod Rx/Tx pins: (also used as programming port MOSI/MISO)

#define IPOD_RX 0x01

#define IPOD_TX 0x02

// ***************** COMMANDS *******************


#define PLAY2 0

#define SKIPR2 1

#define SKIPL2 2

#define REL2 3

const unsigned char cmd_arr[]={

  /* mode 2 commands */

  /* play command */

  0x00, 0x00, 0x01,

  /* skip right */

  0x00, 0x08,

  /* skip left */

  0x00, 0x10,

  /* button release */

  0x00, 0x00

};

const unsigned int idx_arr[]={

  /* play */

  0,

  /* skip right */

  3,

  /* skip left */

  5,

  /* button release */

  7,

  /* terminate the array */

  9

};

// ipod interface (UART0)

void ipod_uart_init(void)


{

  // At 14.7Mhz, UBRR0 set to 47 gives 19200baud

  UBRR0H = 0;

  UBRR0L = 47;

  /* Enable receiver and transmitter */

  //UCSR0B = (1<<RXEN0)|(1<<TXEN0);

  UCSR0B = (1<<TXEN0);

  /* Set frame format: 8data, N, 1stop bit */

  UCSR0C = 0x06;

}

// This will transmit a single byte across the ipod interface

void ipod_tx_byte( unsigned char data )

{

/* Wait for empty transmit buffer */

while ( !( UCSR0A & (1<<UDRE0)) )

;

/* Put data into buffer, sends the data */

UDR0 = data;

}

// This will calculate the checksum and transmit all bytes

void ipod_tx_bytes(unsigned char mode, unsigned char* arr, unsigned char length)

{

  unsigned int tot;

  unsigned char j;

  unsigned int check;

  unsigned char i;

  tot=length+1+mode;

  for (j=0; j<length; j++)

  {

    tot=tot+arr[j];

  }

  check=0x100-(tot & 0xff);

  ipod_tx_byte(0xff);

  ipod_tx_byte(0x55);

  ipod_tx_byte(length+1);

  ipod_tx_byte(mode);

  for (i=0; i< length; i++)

  {

    ipod_tx_byte(arr[i]);

  }

  ipod_tx_byte((unsigned char)check);

}

// This will play a command from the array

void ipod_tx_cmd(unsigned char cmd)

{

  int i;

  unsigned int index;

  unsigned char length;

  switch (cmd)

  {

    // Mode 2 commands

    case PLAY2:

    case SKIPR2:

    case SKIPL2:

      index=idx_arr[cmd];

      length=(unsigned char) (idx_arr[cmd+1] - idx_arr[cmd]);

      // transmit these commands a few times in case the ipod misses it

      // (will this ever happen?)

      for (i=0; i<3; i++)

      {

        ipod_tx_bytes(2, (unsigned char*)&cmd_arr[index], length);

      }

      // since it was a mode 2 command, now execute 'button release'

      for (i=0; i<3; i++)

      {

        ipod_tx_bytes(2, (unsigned char*)&cmd_arr[idx_arr[REL2]], idx_arr[REL2 + 1] - idx_arr[REL2] );

      }

      break;

  default:

      break;

  }