Group Members

• Nathan Weiss
• Srinivas Ravindran
• Walter Ley

Project Description

The Smart Watch is an activity tracker implemented on Mbed LPC1768. The Mbed is supported along with Bluetooth interface to enable communication with phone. The Adafruit Bluefruit LE establishes the wireless link between the Mbed and a compatible device. The ULCD_144_G2 is a smart color LCD display board with a serial interface that displays the current time. It also shows the current altitude, temperature and number of steps taken. There is also an RGB LED to indicate ambient temperature changes. The MPL3115A2 pressure sensor communicates over the I2C bus the altitude and temperature data. The Inertial Measurement Unit is used to measure the number of steps taken and is in parallel with the altimeter on the I2C bus. An SD card module is provided for reading and updating data such as min/max temperature, altitude and steps taken. The SD card File System is a library that allows SD cards to be accessed as a filesystem, using an SPI interface. Also, there is an on-board battery power supply to drive the clock in the event of power loss to the rest of the system.

Video

Images

Block Diagram

Parts

• 1 x mbed NXP LPC1768 Microcontroller
• 1 x LSM9DS1 IMU
• 1 x MPL3115A2 Pressure Sensor
• 1 x uLCD-144-G2
• 1 x microSD Card Reader
• 1 x Adafruit Bluefruit LE UART
• 1 x CR2032 Battery
• 1 x CR2032 Battery Holder
• 2 x 100 Ohm resistors
• 1 x 180 Ohm resistor

Pin Connections

LSM9DS1 IMU

MPL3115A2 Altimeter

uLCD-144-G2

microSD Card Reader

Adafruit Bluefruit LE UART

RGB LED

To prevent the RGB LED from shorting, resistors are used to drop the current to each leg of the LED as shown below:

Battery Connection

In order to maintain the correct time in the event of power loss, a coin cell battery is also included in the design.

Code