Thursday, November 20, 2014

The bigger picture

Tonight I will try to list the hardware components I plan to include in the system, and try to figure out how to connect them all.
  • Input/output devices outside the door, controlled by an Arduino-like microcontroller:
  • Sensors and actuators in the door and door frame, controlled by a Raspberry Pi:
    • Ruko/Abloy EL582 solenoid lock.
      1 output to control the solenoid (through a MOSFET).
      2 inputs for position of bolt and handle.
    • A reed contact and a recessed magnet mounted in door and frame to detect if the door is really closed.
      1 input.
    • A microswitch in back of the strike plate to detect if the dead bolt is in place.
      1 input.
  • Power supply - supplied by 230VAC mains.
    • A 12V 7.2Ah lead acid battery so the access control system can keep running during power failures.
    • A battery charger (230VAC => 12VDC).
    • 12V => 5V and/or 3.3V regulators for the electronics.
    • Perhaps use an analog input to monitor the voltage of the 12V battery.
  • Wild ideas:
    • A PIR-sensor to detect unathorized entry.
    • Monitor my Kibbi-sensors for open windows.
    • A 12V sirene - if unauthorized entry is detected.
      1 output (through a MOSFET).
    • A laser-grid in front of the door - to signal "armed" status ;-)
And now it is late, and the connections must wait for another time. SPI, I²C, serial, RS485 - who knows.