Published August 4, 2020 © GPL3+

Sound-Following Robot

A sound-following robot using two microphone sensors on the TI-RSLK MAX!

BeginnerFull instructions provided2,939

Things used in this project

Hardware components

Texas Instruments TI Robotics System Learning Kit TI-RSLK

DAOKI High Sensitivity Microphone Sensor

Breadboard (generic)

Jumper wires (generic)

Software apps and online services

Texas Instruments Energia

Story

OVERVIEW

As a part of the 2020 TI Summer Robotic Design Challenge, I built a sound-following robot using the TI-RSLK MAX. The idea behind the project was to simulate search and rescue using the human voice. While computer vision, heat detection, or a combination of the three could have also been used, a single factor, voice, was chosen due to the time and budget constraints of the project.

As a proof of concept, this version of the project is a sound-following robot, rather than a voice-following robot. See the "Challenges and Improvements" section for how it can be adapted for voice detection.

PROJECT DETAILS

This sound-following robot includes two microphone sensors, one on each side of the breadboard. This allows the robot to detect sounds coming from both its left and its right. Every 2.35 seconds, digital readings are taken from both microphone sensors. (Note: 2.35 seconds was used because that was how long the robot took to turn 90 degrees at the chosen speed. For future versions of the project, an "aiming" system can be implemented for more accurate turns.)

If the value from the left sensor is high while the value from the right sensor is low, the robot will turn left, and vice versa. If the value from both microphones is high, the robot will move forward toward the sound.

Sound-Following Robot Demo

CHALLENGES AND IMPROVEMENTS

Though this project pivoted toward sound detection rather than voice detection, my original plans to create a voice-following robot have not been abandoned!

For future iterations of this project, there are several alterations I will be looking into:

1. Using analog microphone sensors (to detect human-voice frequencies only)

2. Adding a third microphone (to help the robot determine if the sound is coming from in front or behind)

3. Implementing an angle detection system (to help the robot accurately turn toward the audio source)

Stay tuned for updates!

CONCLUSION

Participating in the 2020 TI Summer Robotic Design Challenge gave me invaluable experience with the electrical design process. I am excited to employ my knowledge in future iterations of this project and beyond!

Special thanks to Mark Easley of the TI University Program for his support!

Code

Sound-Following Robot

//Carol Zhang - 2020 TI Summer Design Challenge - Sound-Following Robot

#include "Energia.h"
#include "SimpleRSLK.h"

const int leftMic = 9;
const int rightMic = 10;

boolean leftReading = 0;
boolean rightReading = 0;

void setup() {
  
  Serial.begin(115200);
  delay(1000);
  setupRSLK();

  //Set microphone sensors to be system input
  pinMode(leftMic, INPUT);
  pinMode(rightMic, INPUT);
}

void loop() {

  bool hit_obstacle = false;
  Serial.println("Searching for sound...");
  enableMotor(BOTH_MOTORS);

  setMotorDirection(LEFT_MOTOR, MOTOR_DIR_FORWARD);
  setMotorDirection(RIGHT_MOTOR, MOTOR_DIR_FORWARD);
  
  //Check microphones for sound
  rightReading = digitalRead(rightMic);
  leftReading = digitalRead(leftMic);
  
  if (leftReading==LOW && rightReading==LOW) 
  { 
    Serial.println("No sound detected!");
  }
  else if (leftReading==LOW && rightReading==HIGH)
  {
    //If sound detected on the right, robot will turn right
    Serial.println("Sound detected on the right!");
    setMotorSpeed(RIGHT_MOTOR, 10);
    delay(2350);
  }
  else if (leftReading==HIGH && rightReading==LOW)
  {
    //If sound detected on the right, robot will turn left
    Serial.println("Sound detected on the left!");
    setMotorSpeed(LEFT_MOTOR, 10);
    delay(2350);
  }
  else 
  {
    //If sound detected on the both mics, robot will move forward
    Serial.println("Sound detected from both microphones!");
    setMotorSpeed(BOTH_MOTORS, 10);
    delay(2350);
  }

  disableMotor(BOTH_MOTORS);
}

Credits

Carol Zhang

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