ACKsess

Project: ACKsess
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State	Active
Members	Vicarious, Prodigity, xopr
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Description	Knock knock.
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synopsis

knock knock.

current implementation

The now working ACKsess implementation has several advantages over the old broken one, that broke.

• Heartbeat: it pulsates the LED every 5 seconds or so, to indicate it's active
• Better feedback (blink if door is unlocked)
• Brute force protection (locks 30 seconds after a failed authentication, pulsates very fast as a tamper indication)
• Faster response (shortened the delay for faster response)
• Opens on powerup/reset. This way, the reset button can be used to open the door
• Various code cleanup/alignment/update
• (NEW) it beeps (as a helping aid)!

images

Some images

• 

  iButton reader inside the door handle hole

• 

  first version of door lock mechanism

• 

  Awesome door handle (press fire to open)

• 

  Joystick internals

hardware

The joystick contains a print that fits snugly, with an Arduino pro mini.

arduino Mega 1280

The print has print connectors, so everything can pop off easy.

You can use a USB to serial adapter (came with the pro mini) for debugging on 115200 baud.

Joystick PCB

The PCB receives power, and uses a 7805 to power the Arduino.

Arduino pins

1. not used
2. reader pin: reader 'data' pin, 4k7 pull up to 5v
3. led pin: uses pwm heart beat every 5 seconds and blinks fast if the door is unlocked
4. button pin: for use for external opener, pullup (connect to ground to trigger)
5. relay pin: set high to pull relay pin to low
6. not used
7. not used
8. not used
9. buzzer pin: for audio feedback

• The NPN transistor used is a BC548 (goes up to 500mA), drived with a 100-300 something ohm resistor on the base (from the top of my head).
• Note that is has a diode (1n4000 something) antiparallel between collector and emittor as coil reverse voltage protection
• The onewire pull up used is 4k7 to 5v

DS9092L iButton probe

I had to reverse engineer the wiring somewhat (connector was gone), but here it is: DS9092L iButton probe datasheet Pinout:

1. GND (blue)
2. Data (onewire) (green)
3. LED cathode (-) (yellow)
4. LED anode (+) (orange)

software

Most of ACKsess.ino:

#include <OneWire.h>

const int relayPin  = 5;     // the number of the relay pin
const int ledPin    = 3;     // the number of the LED pin (change to 13 to see the onboard led)
const int readerPin = 2;     // the number of the iButton reader pin
const int buttonPin = 4;     // the number of the pushbutton pin
const int buzzerPin = 9;     // the number of the buzzer pin

OneWire ds( readerPin );
byte addr[ 8 ];
String keyStatus = "";

byte allowedButtons[][6] = {
  /* ADD YOUR BUTTONS TO AUTHORIZE HERE */
};

byte disallowedButtons[][6] = {
  /* ADD THE BUTTONS TO IGNORE HERE */
};

void setup(void)
{
  Serial.begin(115200);
  pinMode( buttonPin, INPUT_PULLUP );
  pinMode( ledPin, OUTPUT );
  pinMode( relayPin, OUTPUT );
  
  Serial.println( "ACKsess initialized" );
  Serial.print( "number of keys: " );
  Serial.println( sizeof( allowedButtons ) / 6 );

  // Open the door upon power up and (on board) reset
  openDoor( true );
}

byte nState = 0;
byte nLedVal = 0;
bool bTamper = false;
void loop(void)
{
  switch ( nState )
  {
    case 0: // forward, led fade in
      nLedVal++;
      if ( nLedVal >= 255 )
        nState++;

      if ( bTamper )
          analogWrite( ledPin, nLedVal & 32 );
      else
          analogWrite( ledPin, nLedVal );

      delay( 1 );
      break;

    case 1: // backward, led fade out
      nLedVal--;
      if ( nLedVal <= 0 )
        nState++;

      if ( bTamper )
        analogWrite( ledPin, nLedVal & 32 );
      else
        analogWrite( ledPin, nLedVal );

        delay( 1 );
      break;

    default: // idle
        nState++;
        delay( 500 );

        if ( nState >= 10 )
          nState = 0;

      break;
  };

  // If the external button was pushed, open the door
  if ( digitalRead( buttonPin ) == LOW )
    openDoor( true );

  // Check keys twice each fade and on every idle state step
  if ( (nLedVal == 127) || ( nState > 1 ) )
  {
    // Store the button info and read the keycode
    getKeyCode( );
    if( keyStatus == "ok" )
    {
      // We have a correct key type, authenticate it
      Serial.print("00");
      for( byte i = 5; i > 0; i--)
      {
        Serial.print( ":" );
        Serial.print(addr[i], HEX);
      }
      Serial.println( "" );

      // Either open the door, or lock the system for 30 seconds
      if ( authenticateKey( addr, false ) )
      {
        bTamper = false;
        openDoor( false );
      }
      else if ( !authenticateKey( addr, true ) )
      {
        bTamper = true;
        Serial.println( "ACKsess denied!" );
        tone( buzzerPin, 600, 3000 );
        delay( 30000 );
      }
      else
      {
        Serial.println( "ACKsess filtered" );
        tone( buzzerPin, 600, 500 );
        delay( 1000 );
        tone( buzzerPin, 600, 500 );
        delay( 1000 );
        tone( buzzerPin, 600, 1000 );
      }
    }
  }
}

void openDoor( bool _buttonPressed )
{
  Serial.println( "ACKsess granted!" );

  // Trigger the relay
  digitalWrite( relayPin, HIGH );

  // Blink the led fast for about 3 seconds
  for ( byte n = 0; n < 3; n++ )  // 250+250*6 500+500*3
  {
    digitalWrite( ledPin, HIGH );
    tone( buzzerPin, 1000, 250 );
    delay( 250 );
    digitalWrite( ledPin, LOW );
    delay( 250 );
  }

  // Relay off
  digitalWrite( relayPin, LOW );
}

void getKeyCode()
{
  byte present = 0;
  byte data[ 12 ];
  keyStatus="";

  if ( !ds.search( addr ) )
  {
    ds.reset_search( );
    return;
  }

  if ( OneWire::crc8( addr, 7) != addr[ 7 ] )
  {
    keyStatus = "CRC invalid";
    return;
  }

  keyStatus = "ok";
  ds.reset( );
}

boolean authenticateKey( byte* _button, bool _includeIgnore )
{
  /* SECURITY THROUGH OBSCURITY, VISIT US TO SEE SOME EXAMPLES */
  return false;
}

todo

• add picture of the internals
• have battery backup (implement stand-by mode, might need a refit of the pull-up)
• check if we need a power-on-lock or power-off-lock, and add an appropriate power design
• audit the authentication method
• Create better method to store and revoke keys on the whole