ECE 110/120 Honors Lab Section : Electronic Lock

Statement of Purpose

Our group's goal is to make an electronic lock with logic gates and Arduino. We will combine several AND, OR and NOT gates to make a lock that will only unlock if several buttons are pressed in a certain order. The correspondence of the buttons to the inputs, so the password can be changed without changing the wiring. If we have enough time, a blue tooth unlock function may be add to the lock.

Background Research

As we've learned about combining basic logic operators to create Boolean functions, we suppose we can make a lock by combining several logic gates that will only have True only when some certain inputs are True. When we research for projects that use logic gates to make electronic locks, we found an example which only unlocks when buttons are pressed in certain sequence. This function is accomplished by combining more gates. To make some innovations, we decide to use Arduino to make it easier to change password, and make the lock be able to add more functions if we have extra time. This design might seems a bit redundant as the logic circuit is not necessary to achieve the function of the lock, but this design is very beneficial for us to explore both Arduino programming and logic circuits. 

Block Diagram / Flow Chart

System Overview

Start: the system needs to be powered to operate.

Buttons: the direct input for the users to enter password, there are supposed to be six or more buttons.

Arduino: It has two functions in the system. First, it receives the inputs from buttons, and convert it to another sequence based on the preset relations. For example, press the button 6 corresponds to output 1 of                 Arduino, thus the password can be easily changed by programming. Also, the logic circuit only gives True signal, so we need to use Arduino to receive this signal and drive the servo to unlock.

Logic circuit: There are the same number of inputs as the buttons, the output will only be 1 if the inputs are true in certain sequence. There will also be an input in the circuit to reset the circuit when password is                   incorrect.

Servo: A basic 9G servo motor to perform the unlock action. 

Parts

Servo Motors

Quantity: 2

Model Number: HS-311

Purpose: To perform unlock action

Vendor: ECE Supply Centre

Price: $13.86 each

Arduino Board

Quantity: 1

Model Number: Arduino Uno R3 SMD 

Purpose: To set password and control the servo

Vendor: Honor lab Inventory

Price: 18.66

Full Size Bread Board

Quantity: 1

Purpose: for wiring

Vendor: Honor lab Inventory

Wiring (Given)

Possible Challenges

The biggest challenge might happen with the logic circuit, as it would much more difficult than any Boolean functions we have met before, so it might be possible that we cannot come up with the correct design. The wiring would also be an issue as there are multiple gates.

Reference

https://hackaday.io/project/26108-electronic-key