Circuit Documentation

Summary of the Circuit

This circuit is designed to interact with the physical environment using an Arduino UNO as the central processing unit. It features an HC-SR04 Ultrasonic Sensor for distance measurement, an SG90 servo motor for directional movement, a speaker for audio output, and an SD module for audio file storage and playback. The primary function of the circuit is to detect objects at a specific distance (2 meters) using the ultrasonic sensor. Upon detection, the speaker will output a verbal warning, and the servo motor will pivot to check for clear paths on either side. The speaker will then instruct on which direction to turn based on the sensor readings from the servo's adjusted positions.

Component List

Arduino UNO

• Microcontroller board based on the ATmega328P
• Provides I/O pins and power supply pins for interfacing with other components

HC-SR04 Ultrasonic Sensor

• Measures distances by emitting ultrasonic waves and measuring the time taken for the echo to return
• Operates on a 5V supply

SG90 Servo Motor

• A small and lightweight servo motor capable of precise control
• Operates on a 5V supply and receives PWM signals for positioning

Speaker

• An audio output device used to play sounds or verbal instructions
• Requires a digital signal for operation

SD Module

• A storage module for SD cards
• Used to store audio files that are played through the speaker

Wiring Details

Arduino UNO

• IOREF connected to SD module VCC
• 3.3V connected to HC-SR04 Ultrasonic Sensor VCC
• 5V connected to SG90 servo motor 5V
• GND connected to HC-SR04 Ultrasonic Sensor GND, SG90 servo motor GND, Speaker -, and SD module GND
• D13 connected to SD module SCK
• D12 connected to SD module MISO
• D11 connected to SD module MOSI
• D10 connected to HC-SR04 Ultrasonic Sensor ECHO
• D9 connected to HC-SR04 Ultrasonic Sensor TRIG
• D6 connected to Speaker +
• D5 connected to SG90 servo motor PWM
• D4 connected to SD module CS

HC-SR04 Ultrasonic Sensor

• VCC connected to Arduino UNO 3.3V
• TRIG connected to Arduino UNO D9
• ECHO connected to Arduino UNO D10
• GND connected to Arduino UNO GND

SG90 Servo Motor

• PWM connected to Arduino UNO D5
• 5V connected to Arduino UNO 5V
• GND connected to Arduino UNO GND

Speaker

• + connected to Arduino UNO D6
• - connected to Arduino UNO GND

SD Module

• CS connected to Arduino UNO D4
• SCK connected to Arduino UNO D13
• MOSI connected to Arduino UNO D11
• MISO connected to Arduino UNO D12
• VCC connected to Arduino UNO IOREF
• GND connected to Arduino UNO GND

Documented Code

/*
 * This Arduino sketch controls a servo motor and a speaker using an ultrasonic
 * sensor. When the sensor detects an object exactly 2 meters away, the speaker
 * will say "roadblocks detected, stop". The servo motor will then check its
 * right and left to determine which direction is clear of obstacles. The
 * speaker will then announce "turn right" or "turn left" based on the clear
 * direction.
 */

#include <Servo.h>
#include <SD.h>
#include <TMRpcm.h>
#include <SPI.h>

#define TRIG_PIN 9
#define ECHO_PIN 10
#define SERVO_PIN 5
#define SPEAKER_PIN 6
#define SD_ChipSelectPin 4

TMRpcm tmrpcm;
Servo myServo;

void setup() {
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(SPEAKER_PIN, OUTPUT);
  myServo.attach(SERVO_PIN);
  Serial.begin(9600);

  // Initialize SD card
  if (!SD.begin(SD_ChipSelectPin)) {
    Serial.println("SD card initialization failed");
    return;
  }
  Serial.println("SD card initialized");

  // Initialize TMRpcm
  tmrpcm.speakerPin = SPEAKER_PIN; // Pin connected to the speaker or amplifier
  // ... other setup code ...
}

void loop() {
  long duration, distance;
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  duration = pulseIn(ECHO_PIN, HIGH);
  distance = (duration / 2) / 29.1;

  if (distance == 200) { // 2 meters
    speak("roadblocks detected, stop");
    delay(1000);
    int rightDistance = checkDirection(90); // Check right
    int leftDistance = checkDirection(0); // Check left
    if (rightDistance > leftDistance) {
      speak("turn right");
    } else {
      speak("turn left");
    }
  }
  delay(500);
}

int checkDirection(int angle) {
  myServo.write(angle);
  delay(1000);
  long duration, distance;
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  duration = pulseIn(ECHO_PIN, HIGH);
  distance = (duration / 2) / 29.1;
  return distance;
}

void speak(const char* message) {
  Serial.println(message);
  if (strcmp(message, "roadblocks detected, stop") == 0) {
    tmrpcm.play("stop.wav"); // Play "stop.wav" from the SD card
  } else if (strcmp(message, "turn right") == 0) {
    tmrpcm.play("turnright.wav"); // Play "right.wav" from the SD card
  } else if (strcmp(message, "turn left") == 0) {
    tmrpcm.play("turnleft.wav"); // Play "left.wav" from the SD card
  }
}

This code is responsible for the operation of the circuit. It initializes the components, reads the distance from the ultrasonic sensor, and controls the servo and speaker based on the sensor's readings. The speak function plays audio files from the SD card corresponding to the detected situation.