Arduino Robotic Arm Help me

Using Arduino Microcontrollers
1

Hello everyone, I'm making a prosthetic robotic arm controlled by an EEG (Nuerosky Mindwave 2) and I'm having problems with the servomotors and I think it's because of the programming.
1- I'm using 4 MG995 servomotors and 1 DS3225mg servomotor
2- 4 of the servomotors (all MG995) don't stop turning and the DS3225mg servomotor doesn't turn and I don't understand the reason, whether it's because of incompatibility or because of the power supply.
Code:

#include <SoftwareSerial.h>
#include <Servo.h>

// Definición de los servomotores
Servo pinkie;
Servo ring;
Servo middle;
Servo index;
Servo thumb;

// Estados lógicos para cada dedo

int pinkieL = 180;
int pinkieH = 90;
int ringL = 180;
int ringH = 80;
int middleL = 0;
int middleH = 126;
int indexL = 100;
int indexH = 15;
int thumbL = 0;
int thumbH = 123;
#define BAUDRATE 57600  // Velocidad en 57600 baudios para comunicación Bluetooth
#define DEBUGOUTPUT 0   // Habilitar lectura de bluetooth para depuración

// Variables de CHECKSUM
byte generatedChecksum = 0;
byte checksum = 0; 
int payloadLength = 0;
byte payloadData[64] = {0};
byte poorQuality = 0;
byte attention = 0;
byte meditation = 0;

// Variables del sistema
long lastReceivedPacket = 0;
boolean bigPacket = false;

SoftwareSerial bluetooth(10, 11); // RX, TX

void setup() {
  // Inicializar los servos en los pines correspondientes
  pinkie.attach(9);
  ring.attach(6);
  middle.attach(5);
  index.attach(3);
  thumb.attach(13);
 
  // Inicializar la comunicación serial con el módulo Bluetooth
  bluetooth.begin(BAUDRATE);  
  Serial.begin(9600); // Para depuración
  Serial.println("Sistema iniciado. Esperando datos de NeuroSky...");
  
  // Inicializar los servomotores en la posición abierta
  pinkie.write(pinkieL);
  ring.write(ringL);
  middle.write(middleL);
  index.write(indexL);
  thumb.write(thumbL);

  // LEER DATOS DEL BLUETOOTH
  delay(2000);
}

byte ReadOneByte() {
  int ByteRead;

  while (!bluetooth.available());
  ByteRead = bluetooth.read();

  #if DEBUGOUTPUT  
    Serial.print((char)ByteRead);   // Echo del byte para depuración
  #endif

  return ByteRead;
}

void loop() {
  // Buscar bytes
  if (ReadOneByte() == 170) {
    if (ReadOneByte() == 170) {

      payloadLength = ReadOneByte();
      if (payloadLength > 169)  // Payload length can not be greater than 169
        return;

      generatedChecksum = 0;        
      for (int i = 0; i < payloadLength; i++) {  
        payloadData[i] = ReadOneByte();  // Leer payload en memoria
        generatedChecksum += payloadData[i];
      }   

      checksum = ReadOneByte();  // Leer byte de checksum      
      generatedChecksum = 255 - generatedChecksum;  // Tomar complemento uno del checksum generado

      if (checksum == generatedChecksum) {    
        poorQuality = 200;
        attention = 0;
        meditation = 0;

        for (int i = 0; i < payloadLength; i++) {  // Parsear el payload
          switch (payloadData[i]) {
            case 2:
              i++;            
              poorQuality = payloadData[i];
              bigPacket = true;            
              break;
            case 4:
              i++;
              attention = payloadData[i];                        
              break;
            case 5:
              i++;
              meditation = payloadData[i];
              break;
            case 0x80:
              i = i + 3;
              break;
            case 0x83:
              i = i + 25;      
              break;
            default:
              break;
          }
        }

        #if DEBUGOUTPUT
          Serial.print("PoorQuality: ");
          Serial.print(poorQuality, DEC);
          Serial.print(" Attention: ");
          Serial.print(attention, DEC);
          Serial.print(" Time since last packet: ");
          Serial.print(millis() - lastReceivedPacket, DEC);
          Serial.println();
        #endif

        if (bigPacket) {
          if (poorQuality == 0) {
            // Determinar el gesto basado en el nivel de atención
            switch (attention / 20) {
              case 0:  // Open
                pinkie.write(pinkieL);
                ring.write(ringL);
                middle.write(middleL);
                index.write(indexL);
                thumb.write(thumbL);
                break;
              case 1:  // Grip (thumb and index)
                pinkie.write(pinkieL);
                ring.write(ringL);
                middle.write(middleL);
                index.write(indexH);
                thumb.write(thumbH);
                break;
              case 2:  // Grip (thumb and middle)
                pinkie.write(pinkieL);
                ring.write(ringL);
                middle.write(middleH);
                index.write(indexL);
                thumb.write(thumbH);
                break;
              case 3:  // Point (with index)
                pinkie.write(pinkieH);
                ring.write(ringH);
                middle.write(middleH);
                index.write(indexL);
                thumb.write(thumbH);
                break;
              case 4:  // Closed
                pinkie.write(pinkieH);
                ring.write(ringH);
                middle.write(middleH);
                index.write(indexH);
                thumb.write(thumbH);
                break;
            }
          }
        }        
        bigPacket = false;        
      } else {
        // Error de Checksum
        Serial.println("Error de Checksum");
      }
    }
  }
}
2

Show a wiring diagram, and describe your power supply.

Which two?

3

nono, all MG995 dont stop. This is the diagram I used, but the board is an Arduino Uno R3 and the Bluetooth modem is the HC-05, the servo motors are connected to pins 9,6,5,3 and 13, the servo motor connected to pin 13 is the one that does not start (DS3225mg) and the power supply is my PC. All components are connected to GND and 5V.

image
image1755×1293 287 KB

4

Your drawing is missing your power supply. You can not power five servos from a Nano.

  1. Remove the Nano VCC/GND jumpers.
  2. Place a 5v power supply on the power and ground rails.
  3. Power your Nano with the USB.

Report your findings.

5

im not have arduino nano, i have Arduino Uno R3, The diagram sent is the one I based the servomotor connections on, but all the components (HC-05, All servomotor) are connected to 5v and GND

6

Have you tested the servo motors by themselves in a different sketch without the mind reader?

7

yep, with all servomotor. This is the code I tried

#include <Servo.h>

Servo thumb;

void setup() {
  thumb.attach(13);
  thumb.write(90); // Posición media
}

void loop() {
  // Prueba con diferentes posiciones
  thumb.write(0);  // Posición 0°
  delay(1000);
  thumb.write(90); // Posición 90°
  delay(1000);
  thumb.write(180); // Posición 180°
  delay(5000);
  thumb.write(0);
  delay(5000);
8

What sort of power supply do you have? The 5V rail from the Arduino cannot power all of those servos.

9

i dont have any power supply, What would you recommend me to do?
If there is no adequate power supply, should it not turn on?

10

It will turn on but it may not be able to make the servos turn. It's just too weak. If you try to pull too much current there you will damage your Arduino.

There is much written about this topic on the internet. Spend a little time searching this forum or google and you will find all sorts of information on how to power a project. This is one of the most common mistakes that new users make and it's well covered.