IoT Touchpad Lock

Group Members

Christian Harris
Ernest Williams

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Project Description

The purpose of this project was to create a system that would allow users to monitor a locked device using a Bluetooth device. This Bluetooth device will show the last user that unlocked the device, and also allows the user to unlock the device using the Bluetooth device. This device can be physically unlocked using a capacitive touch keypad sensor.

To allow this, the following devices were used:

  • Adafruit Bluefruit LE UART Friend
  • MPR121 I2C Capacitive Touch Sensor
  • Shiftbrite V2.0
  • mbed LPC1768

Wiring Guides

The devices were wired according to the tables below:

Adafruit Bluefruit LE UART Friend

mbedAdafruit BluefruitExternal 5V DC Supplly >= 500 MA
GndGnd
p10TXO
p9RXI
VIN5V DC
ncRTS
GndCTS

MPR121 I2C Capacitive Touch Sensor

mbedMPR121Pullup Resistors
GndGnd
p28SDA4.7K
p27SCL4.7K
p26IRQ
Vout(3.3V)VCC

Shiftbrite V2.0

mbedShiftbriteExternal 5V DC Power Supply >= 500 MA
GndGnd
p11DI
p15LI
p16EI
p13CI
V+5V DC

Code Description

The code below begins by sending text via Bluetooth to a UART device connected to the Adafruit Bluefruit that allows the lock to be monitored and unlocked via bluetooth. After this is completed, The touchpad can be used to initiate interrupt routines that save four key presses. These key presses represent the code being entered. Once four keys are pressed. The code is checked against the saved code values. If the code matches, the Shiftbrite becomes green, and information of who unlocked the device is printed to the Bluetooth terminal. If the code is incorrect, the Shiftbrite becomes red. To enter a code via Bluetooth, the user must send the letter 'a'. Once this is sent they are prompted to enter their code. They can enter '1111' at once, or one value at a time.

Import programBluetooth

The purpose of this project was to create a system that would allow users to monitor a locked device using a Bluetooth device. This Bluetooth device will show the last user that unlocked the device, and also allows the user to unlock the device using the Bluetooth device. This device can be physically unlocked using a capacitive touch keypad sensor.

Video Demonstration


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