Arduino‑Powered Robot Arm with Custom Controller – Servo & Potentiometer Build

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Arduino IDE

About this project

I made obot arm and its controller.

Constitution

The robot arm uses three conventional PWM servos, and each angle is controlled by a variable resistor. The rotary potentiometer used B curve 10k ohm.

Robot Arm Production

Two DS3115 servo motors were used in the vertical direction, and MG995 servo motor was used in the swing direction.

Controller Production

I made a controller case with a 3D printer.

A hole and a positioning hole for screwing through the knob of the rotary potentiometer, and a dent for inserting the knob are provided.

Assemble the fabricated parts and three rotary potentiometers to complete!

The rotary potentiometer has now been placed in the same direction as the rotation axis of the servomotor of the robot arm!

Arduino Code

This simple code simply reads the value of the rotary potentiometer with an analog pin, converts it to an angle, and inputs it to the corresponding servo.

#include <Servo.h>

Servo myservo1, myservo2, myservo3;

float th1=90.0,th2=90.0,th3=90.0;
float val1, val2, val3;

void setup() {
    Serial.begin(9600);
    myservo1.attach(9, 500, 2420);  //MG995
    myservo2.attach(10, 820, 2140); //DS3115
    myservo3.attach(11, 820, 2140); //DS3115
    set_servo();
}

void loop() {
    val1 = analogRead(A1);
    val2 = analogRead(A2);
    val3 = analogRead(A3);

    th1 = map(val1, 170.0, 880.0, 0.0, 180.0);
    if(th1 >= 180.0){
        th1 = 180.0;
    }else if(th1 <= 0.0){
        th1 = 0.0;
    }

    th2 = map(val2, 150.0, 860.0, 0.0, 180.0);
    if(th2 >= 180.0){
        th2 = 180.0;
    }else if(th2 <= 0.0){
        th2 = 0.0;
    }

    th3 = map(val3, 860.0, 160.0, 0.0, 180.0);
    if(th3 >= 180.0){
        th3 = 180.0;
    }else if(th3 <= 45.0){
        th3 = 45.0;
    }

    set_servo();
}

void set_servo(){
    myservo1.write(th1);
    myservo2.write(th2);
    myservo3.write(th3);
}

Operation

Complete by wiring the rotary potentiometer and connecting it to Arduino!

Custom parts and enclosures