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For more information about the first version of the system, see the events Doorhacking and Doorhack2.7 Since the first system was unstable and damaging to the remote, a complete redesign was called, with special attention to robustness and proper stable operation.

System architecture

All hardware will be divided in two cases:

  • An old Lantronix Lantronix terminal server 1U mounted in the hackerspace rack
  • A plastic IP65 junction box to be placed in front of the gate

The exception to this division is the USB GSM modem, which will be placed outside the hackerspace rack for reception reasons.

A cat5 UTP cable will connect both boxes.


Lantronix case

Power supply

The original Lantronix PS can be reused. It gives the following outputs on a 6-pin molex:

Pin Number Color Voltage
1 RED +12
2 & 3 BLUE +5
4 & 5 BLACK Ground

Beagle Board

pinout on the beagleboard towards the gate opener:

  • pin 28: black (GND)
  • pin 24: white
  • pin 1 (bottom): red (1V8)




The stripboard shall contain the following:

  • Molex power input connector from the power supply
  • 2,1mm power output connector to the beagleboard
  • RJ45 output connector to the IP65 case
    • left first RJ45 connector on terminal server acts as output connector
    • the pins on the connector have all been soldered, T568B style.

On the RJ45 connector shall be present:

  • one pair carrying the signal to the relais (+5 Volt if on, plus ground)
    • we will use the blue pair
    • the +5V comes from the PSU but the beagle bord does the switching
  • one pair carying power to the remote (+12 Volt continuous plus ground)
    • we will use the brown pair for this

LED controller

32 leds + controller are present on the case. Connection to the controller is made by 10-pin flatcable. Low-priority, but nice addition to the project.

IP65 Junction box



The stripboard shall contain the following:

  • RJ45 connector to receive power & signal
  • Adequate protection & decoupling
  • Voltage regulation circuit for a local current loop
  • Signal input buffer
  • Relay



For the gatekeeper python script, see Gatekeeper