NRF24L01 Bluetooth Servo Control

Introduction

You will learn how to connect two Arduinos using Bluetooth in this instructable. To use Bluetooth, we will use two NRF sensors, one for each Arduino. Two potentiometers are used with the transmitter Arduino to control the two servos on the receiver Arduino.

1. Arduino Uno x2
2. Servo x2
3. Potentiometer x2
4. NRF 24 x2
5. Jumper Wires
6. Breadboard x2

Connect Bluetooth modules, servos and potentiometers.

Use a breadboard to create a ground and power terminal for each Arduino.

Connect each Arduino to a Bluetooth module using a breadboard

1. · CSN - 8
2. · CE - 9
3. · MOSI - 11
4. · MISO - 12
5. · SCK - 13

Connect the servos to the receiver Arduino

Servo 1:

Ground - ground on Breadboard

Power - Power on Breadboard

Signal - 7

Repeat with Servo 2, but put the signal in Pin 6

Connect the potentiometers to the transmitter Arduino

Potentiometer 1:

VCC - power on breadboard

Signal - A0

GND - ground on breadboard

Repeat with Potentiometer 2, but put the input in A2

Full Wiring Diagram:

Install needed libraries

You will need to install libraries for the nRF modules to be used. It can be found directly in IDE. Install this library directly from the Arduino IDE Library Manager. Search for “rf24” and install the one by “TMRh20, Avamander”.

Install code

Transmitter Code:

/ / add all relevant libraries

#include <SPI.h>

#include <nRF24L01.h>

#include <RF24.h>

//declares CE, CSN pins

RF24 radio(9, 8); //(CE, CSN)

//declares analog pins for potentiometers

int potPin = A0;

int potPin2 = A2;

//declares the potentiometer value as an integer

int potValue = 0;

int potValue2 = 0;

//creates an array to hold 4 values

byte Array[4];

//Creates an address for two modules to communicate

const byte address[6] = "99150";

void setup()

{

Serial.begin(9600);

radio.begin();

//sets radio address

radio.openWritingPipe(address);

//declares Arduino as a Bluetooth transmitter

radio.stopListening();

}

void loop()

{

//stores analog(potentiomer 1) reading as an integer

potValue = analogRead(A0);

//Maps the potentiometer reading into degrees of motion for the servo to understand

potValue = map(potValue, 0, 1023, 0, 179);

//sets elements of the arrays

Array[0] = 1;

Array[1] = potValue;

Array[2] = 3;

Array[3] = 4;

//Sends array over radio/Sends commands for servo 1

radio.write(&Array, sizeof(Array));

delay(1);

//stores analog(potentiomer 2) reading as an integer

potValue2 = analogRead(A2);

//Maps the potentiometer reading into degrees of motion for the servo to understand

potValue2 = map(potValue2, 0, 1023, 0, 179);

Array[0] = 2;

Array[1] = potValue2;

Array[2] = 6;

Array[3] = 8;

//Sends array over radio/Sends commands for servo 2

radio.write(&Array, sizeof(Array));

delay(1);

//prints servo position

Serial.println(potValue);

Serial.println(potValue2);

}

Receiver Code:

//include all relevant libraries

#include <SPI.h>

#include <nRF24L01.h>

#include <RF24.h>

#include <Servo.h>

//declares CE, CSN pins

RF24 radio(9, 8); //(CE, CSN)

//declares the potentiometer value as an integer

int potValue = 0;

int potValue2 = 0;

//declares servos

Servo servo1;

Servo servo2;

//creates an address for two modules to communicate

const byte address[6] = "99150";

void setup()

{

//declares pins for servos

servo1.attach(7);

servo2.attach(6);

while (!Serial);

Serial.begin(9600);

radio.begin();

//sets radio address

radio.openReadingPipe(0, address);

//declares Arduino as receiver

radio.startListening();

}

void loop()

{

//reads data from Arduino if available

if (radio.available())

{

//holds incoming message

byte Array[4];

//reads message from other Arduino

radio.read(&Array, sizeof(Array));

//determines that the array is from potentiometer 1

if (Array[0] == 1)

{

potValue = Array[1];

//writes servo 1 value

servo1.write(potValue);}

//determines that the array is from potentiometer 2

if (Array[0] == 2)

{

potValue2 = Array[1];

//writes servo 1 value

servo2.write(potValue2); }

//prints servo position

Serial.println(potValue2);

Serial.println(potValue);

}

delay(10);

}