WiFi-Operated Door Lock
By Tomer Shapira
Student at Tufts University studying Computer Engineering
This project involved automating a door lock. The device was to work using Blynk, an aruduino-compatible phone application, to communicate over WiFi with an ESP8266-capable board (a NodeMCU board was used)
Hardware and Software Used:
The hardware used included a stepper motor (SY28STH45), an h-bridge (SN754410NE), a NodeMCU board, a 5V voltage regulator (L7805CV), and general circuit components (wires, PCB, pin sockets, etc). Two 9V batteries were used to power the circuit: one to drive the motor and one to power the NodeMCU and h-bridge (digital components).
The software used were Arduino IDE and Blynk, an application that allows remote operation of arduino-compatible boards over WiFi.
This video shows the circuit operate. I did not get a chance to produce an interface for the lock (a way to attach the motor to a door lock).
The motor rotates a set distance in one direction once the button “lock” is pressed in the Blynk app. A display in the app then reads the state (“Door Unlocked”). Once the lock button is pressed again, the motor spins in the opposite direction and the display reads “Door Locked”.
Potential Future Improvements:
-Use only one battery: would require building a circuit that can isolate the current being drawn by the motor from the digital components.
-Construct interface with door lock: can be done with 3D-printing
-Find a way to make it not depend on the same WiFi connection: allow access and control from anywhere. This would likely require leaving Blynk and designing a replacement application.
This project can be used as a base for designing simple IoT-type home automation/security systems.
Feel free to contact me if you want to continue with this project and need help.