Circuit Documentation

Summary of the Circuit

This circuit is designed to control multiple servo motors using an Arduino UNO as the main microcontroller, interfaced with an Adafruit PCA9685 PWM Servo Breakout board to drive the servos. Communication with external devices is facilitated by an NRF24L01 transceiver module. The circuit is powered by a 9V battery, and an electrolytic capacitor is used for voltage smoothing.

Component List

Arduino UNO

• Microcontroller board based on the ATmega328P
• It has 14 digital input/output pins, 6 analog inputs, a 16 MHz quartz crystal, a USB connection, a power jack, an ICSP header, and a reset button.

Servo Motors

• Actuators that can be precisely controlled for angular or linear position, velocity, and acceleration.
• Each servo has three connections: ground (gnd), power (vcc), and control signal (pulse).

NRF24L01

• A 2.4GHz transceiver module with an embedded baseband protocol engine.
• It has connections for power (VCC, GND), SPI interface (MOSI, MISO, SCK, CSN), and a Chip Enable (CE) pin.

Adafruit PCA9685 PWM Servo Breakout

• A 16-channel, 12-bit PWM Fm+ I2C-bus LED controller.
• It has connections for power (VCC, GND, PWRIN), I2C interface (SDA, SCL), and PWM outputs for each channel.

9V Battery

• Provides power to the circuit.

Electrolytic Capacitor

• Used for voltage smoothing and filtering.
• It has a capacitance of 0.00001 Farads.

Wiring Details

Arduino UNO

• 3.3V connected to NRF24L01 VCC (3V) and Electrolytic Capacitor (+)
• 5V connected to Adafruit PCA9685 PWM Servo Breakout VCC
• GND connected to Adafruit PCA9685 PWM Servo Breakout GND, NRF24L01 GND, and Electrolytic Capacitor (-)
• A4 (SDA) connected to Adafruit PCA9685 PWM Servo Breakout SDA
• A5 (SCL) connected to Adafruit PCA9685 PWM Servo Breakout SCL
• D9 connected to NRF24L01 CE
• D10 connected to NRF24L01 CSN
• D11 (MOSI) connected to NRF24L01 MOSI
• D12 (MISO) connected to NRF24L01 MISO
• D13 (SCK) connected to NRF24L01 SCK

Servo Motors

• gnd connected to Adafruit PCA9685 PWM Servo Breakout GND
• vcc connected to Adafruit PCA9685 PWM Servo Breakout 5.0V
• pulse connected to respective PWM channels on Adafruit PCA9685 PWM Servo Breakout (PWM0, PWM1, PWM2, PWM3, PWM4, PWM5)

NRF24L01

• VCC (3V) connected to Arduino UNO 3.3V and Electrolytic Capacitor (+)
• GND connected to Arduino UNO GND and Electrolytic Capacitor (-)
• CE connected to Arduino UNO D9
• CSN connected to Arduino UNO D10
• SCK connected to Arduino UNO D13
• MISO connected to Arduino UNO D12
• MOSI connected to Arduino UNO D11

Adafruit PCA9685 PWM Servo Breakout

• VCC connected to Arduino UNO 5V
• GND connected to Arduino UNO GND and all Servo Motors gnd
• PWRIN connected to 9V battery (+)
• PWM0 - PWM5 connected to respective Servo Motors pulse
• SDA connected to Arduino UNO A4
• SCL connected to Arduino UNO A5

9V Battery

• + connected to Adafruit PCA9685 PWM Servo Breakout PWRIN
• - connected to Adafruit PCA9685 PWM Servo Breakout GND

Electrolytic Capacitor

• + connected to Arduino UNO 3.3V and NRF24L01 VCC (3V)
• - connected to Arduino UNO GND and NRF24L01 GND

Documented Code

#include <Wire.h>
#include <Adafruit_PWMServoDriver.h>
#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>

// nRF24L01 Setup: CE and CSN pins
RF24 radio(9, 10);  // CE = Pin 9, CSN = Pin 10
const byte address[6] = "00001";  // Must match transmitter address

// Create PCA9685 PWM driver object
Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver();

int potValues[6];  // Array to store the received potentiometer values

// Servo motor pulse range (150 - 600 is typical for many servos)
int servoMin = 150;
int servoMax = 600;

void setup()
{
  Serial.begin(9600);

  // Initialize the nRF24L01
  radio.begin();
  radio.openReadingPipe(0, address);  // Set the receiver address
  radio.setPALevel(RF24_PA_MIN);
  radio.startListening();  // Set as receiver

  // Initialize the PCA9685
  pwm.begin();
  pwm.setPWMFreq(50);  // Set PWM frequency to 50Hz (for servos)
}

void loop()
{
  // Check if data is available
  if (radio.available()) 
  {
    // Receive the potentiometer values
    radio.read(&potValues, sizeof(potValues));

    // Use the potentiometer values to control the servos
    for (int i = 0; i < 6; i++) 
    {
      int pulseWidth = map(potValues[i], 0, 1023, servoMin, servoMax);  // Map to servo pulse width
      pwm.setPWM(i, 0, pulseWidth);  // Set PWM for the ith servo
    }
  }
}

This code is responsible for initializing the NRF24L01 module and the PCA9685 PWM driver, receiving potentiometer values wirelessly, and controlling the servo motors by mapping the received values to the appropriate pulse widths.