Overview

By: James Plager and Craig Raslawski

For our final project, we created an autonomous navigating robot that tracks its position over time. Logged position data is sent over bluetooth serial interface and displayed in a C# GUI on a supporting computer.

The default behavior of this robot, whose behavior resembles that of a Roomba vacuum cleaner, is to navigate about its surroundings using onboard sensors to avoid collisions with objects in the environment. The option to take manual control of the bot exists. Control can be taken from the GUI on a computer and used to navigate the bot over Bluetooth.

Autonomous navigation utilizes onboard ultrasonic and IR sensors. The ultrasonic sensor is used to detect obstacles in front of the robot, and the IR sensor on the side of the bot detects once it has driven past the detected obstacle.

Components

• LSM9DS1 IMU
• HC-06 Bluetooth Serial Pass-Through Module
• IR Sensor
• Shadow Chassis + DC Motors x2
• HC-SR04 Ultrasonic Sensor
• External Power Sources
• Bluetooth Control C# GUI

LSM9DS1 IMU

Atomic Market HC-06 Bluetooth Serial Pass-Through

The RXD pin needs to be pulled down to ground.

IR Distance Sensor

HC-SR04 Ultrasonic Sensor

External Power

The two DC motors and Bluetooth module draw more power than the mbed can supply. An external power pack will be needed.
Sparkfun sells an external 4xAA battery holder with a barrel jack that will provide the needed power.

For our solution, we used this and a portable phone charger with a stripped USB cable for independently powering the motors and mbed, respectively.

Demos

Picture of bot:

GUI Screenshots

Below image shows GUI setup. You will need to select the appropriate COM port to communicate with the bot.
The "Manual Override" button takes manual control of the bot, and arrow keys are then used to control direction. To start the program, enter the dimensions of the area and press "Begin."

Code

Mbed C++