Hardware Assembly

Security Barrier PCB

The Security Barrier PCB uses 220vAc or 115V 1 phase for actuating the motor Up and Down.
There are 24V DC, 24V AC in some boards even 12V DC, 12V AC available for providing power to accessories and I/O.

in order to interface a Microcontroller with Security Barrier PCB, we need a Relay Circuit.

Circuit

This Circuit was designed keeping in mind the manual controls, hence giving manual buttons from Security Barrier PCB Priority over Microcontroller signals.

• A MOSFET is interfaced between relay and Raspi and is FED 5v to the Gate to keep it Activated.
• The Raspi will Send eg ON/OFF Signal to activate the relay accordingly
• As we ground the terminal to activate the functionality, we connect the functionality terminal to NC of the relay with 24VDC terminal
• When the relay is activated the Terminal will shift to GND of the Output of the Relay
• To give priority to Push Buttons we have interfaced it to the MOSFET
• When the push button is pressed it will do its functionality at the same time MOSFET voltage becomes Zero
  hence Cutting the connection of relay from RASPI.

We take I/O pins 7,8 and 9 from the Microcontroller as we have 3 signals Open, Close and Stop hence we require 3 such connections. We then connect from these pins to CH1, CH2 and CH3 of the Relay Modules
Note:- The pins mentioned are default coded in this project

Working

The Signals are sent from Microcontroller to the Security Barrier PCB through Relays. In case of any Emergency manual buttons are given priority over Microcontroller interface. Hence along with Automated working, there is Strict control over the Mechanism.