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Bluetooth-Controlled Robotic Arm with Arduino and PCA9685

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Circuit Documentation

Summary

This circuit is designed to control three micro servos via Bluetooth commands and a flex sensor using an Arduino UNO. The HC-05 Bluetooth module receives commands from another device, and the Adafruit PCA9685 PWM Servo Breakout is used to control the servos. The servos' positions are updated based on the received Bluetooth data and flex sensor readings.

Component List

  1. HC-05 Bluetooth Module

    • Description: A Bluetooth module used for wireless communication.
    • Pins: Key, VCC, TXD, RXD, State, GND

  2. Micro servo 9G

    • Description: A small servo motor used for precise control of angular position.
    • Pins: GND, +5V, PWM

  3. Arduino UNO

    • Description: A microcontroller board based on the ATmega328P.
    • Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0, A1, A2, A3, A4, A5, SCL, SDA, AREF, D13, D12, D11, D10, D9, D8, D7, D6, D5, D4, D3, D2, D1, D0

  4. Adafruit PCA9685 PWM Servo Breakout

    • Description: A PWM driver board used to control multiple servos.
    • Pins: 5.0V, GND, PWRIN, PWM7, PWM6, PWM5, PWM4, PWM3, PWM2, PWM1, PWM0, VCC, SDA, SCL, OE, PWM15, PWM14, PWM13, PWM12, PWM11, PWM10, PWM9, PWM8

  5. 3.7v LiPo

    • Description: A 3.7V Lithium Polymer battery used to power the circuit.
    • Pins: +Ve, GND

Wiring Details

HC-05 Bluetooth Module

Micro servo 9G (Instance 1)

Micro servo 9G (Instance 2)

Micro servo 9G (Instance 3)

Arduino UNO

Adafruit PCA9685 PWM Servo Breakout

3.7v LiPo

Code Documentation

Arduino UNO Code

/*
 * This Arduino Sketch controls three micro servos via Bluetooth commands and a flex sensor.
 * The HC-05 Bluetooth module receives commands from another device.
 * The Adafruit PCA9685 PWM Servo Breakout is used to control the servos.
 * The servos' positions are updated based on the received Bluetooth data and flex sensor readings.
 */

#include <Wire.h>
#include <Adafruit_PWMServoDriver.h>

Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver();

const int bluetoothRx = 0; // RX pin of HC-05
const int bluetoothTx = 1; // TX pin of HC-05
const int flexSensorPin = A0; // Analog pin for flex sensor

void setup() {
  Serial.begin(9600); // Initialize serial communication
  pwm.begin();
  pwm.setPWMFreq(60); // Analog servos run at ~60 Hz
  pinMode(flexSensorPin, INPUT);
}

void loop() {
  if (Serial.available() > 0) {
    int servoNum = Serial.read();
    int servoPos = Serial.read();
    if (servoNum >= 0 && servoNum <= 2) {
      setServoPosition(servoNum, servoPos);
    }
  }

  int flexValue = analogRead(flexSensorPin);
  int servoPos = map(flexValue, 0, 1023, 0, 180);
  setServoPosition(0, servoPos); // Example: Control servo 0 with flex sensor
  delay(100); // Small delay for stability
}

void setServoPosition(int servoNum, int pos) {
  int pulseLength = map(pos, 0, 180, 150, 600);
  pwm.setPWM(servoNum, 0, pulseLength);
}

Adafruit PCA9685 PWM Servo Breakout Code

void setup() {
  // put your setup code here, to run once:
}

void loop() {
  // put your main code here, to run repeatedly:
}

3.7v LiPo Code

void setup() {
  // put your setup code here, to run once:
}

void loop() {
  // put your main code here, to run repeatedly:
}

This documentation provides a comprehensive overview of the circuit, including a summary, component list, wiring details, and code documentation.