Relay connected to Arduino,
Node MCUor ESP32 and door lock release
The SPDT Relay(30A) is a high-quality Single Pole Double Throw Relay (SPDT). The Relay consists of a coil, 1 common terminal, 1 normally closed terminal, and one normally open terminal. When the coil of the relay is at rest (not energized), the common terminal and the normally closed terminal have continuity.
When the coil is energized, the common terminal and the normally open terminal have continuity. This relay’s coil is rated up to 5V and the contact is rated up to 30A (@250VAC, 30VDC). You can use it to control high current devices.
When the Arduino Pin 7 gets change in status and this should be used to pull the Pin 12 High which would trigger the relay which in turn switches of the door lock there by door to be opened for entry exit of authorised person. What is said about Arduino stands true for Node MCU and ESP32 as well.
