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Lab 4: RF Communication, Navigation & Finalizing Robot

In this lab, we programmed the robot to use its combined components and the separate base station circuit from Lab 2 to navigate a maze and keep itself centered within an aisle 15” wide. The individual goals to be completed are listed below.

No additional hardware was installed during the completion of Lab 4.

Maze Navigation

The robot must use the combined circuits and newly written code to search through the maze for two treasures and stop navigating after finding the second.

Materials:

• Robot Constructed in Labs 1, 2, & 3

Microphone Circuit and FFT

To begin navigating the maze, the robot sits and waits for a specific frequency to be played. The microphone circuit sends the signal to the Arduino, where it is analyzed using the spectrogram resulting from a Fast Fourier Transform (FFT). If the frequency is detected, the robot will immediately begin navigating.

PID Centering and DFS Navigation

The robot must send measurements from the three ultrasonic (US) sensors to the Arduino. The inputs from the US sensors are sent through a Proportional-Integral-Derivative (PID) control function to keep the robot centered. A depth-first search (DFS) algorithm is used to explore the maze and backtrack after reaching a dead end.

Infrared Detection and RF Communication

The robot must navigate the maze in search of two “treasures” made of blinking infrared (IR) LEDs. Treasure detection is assessed by the three phototransistors attached. When an IR LED is detected, its frequency will be relayed through a radio frequency (RF) antenna to the base station where it will be displayed in units of kilohertz. After finding two treasures, navigation ceases.

Fig.1: Completed Robot

Fig. 2: Robot making right turns and using PID control algorithm