how to put external power supply for 90sg servo motor on a motor shield for a project of obstacle avoidance robot? and what is the adjustment on the code?
Welcome to the forum
Connect the positive and GND (negative) of the external supply to servo positive and GND (negative). Connect Arduino GND to servo GND. Connect the servo data wire to an Arduino pin as normal
No adjustment to code is required when using external power for the servo
Please post the details of your project here rather than a link to an external site
is any pin alright? we are to use 6 or 7 pin on the arduino
Showing how to connect an external power source with servo and Arduino.
Use any pin for the servo control signal. It does not have to be a PWM pin. You can use the analog inputs, too (except A6 and A7 on Nano).
is this right?
Please follow the advice given in the link below when posting code, in particular the section entitled 'Posting code and common code problems'
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sorry, but this is our code
//ARDUINO OBSTACLE AVOIDING CAR//
// Before uploading the code you have to install the necessary library//
//AFMotor Library https://learn.adafruit.com/adafruit-motor-shield/library-install //
//NewPing Library https://github.com/livetronic/Arduino-NewPing//
//Servo Library https://github.com/arduino-libraries/Servo.git //
// To Install the libraries go to sketch >> Include Library >> Add .ZIP File >> Select the Downloaded ZIP files From the Above links //
#include <AFMotor.h>
#include <NewPing.h>
#include <Servo.h>
#define TRIG_PIN A0
#define ECHO_PIN A1
#define MAX_DISTANCE 200
#define MAX_SPEED 190 // sets speed of DC motors
#define MAX_SPEED_OFFSET 20
NewPing sonar(TRIG_PIN, ECHO_PIN, MAX_DISTANCE);
AF_DCMotor motor1(1, MOTOR12_1KHZ);
AF_DCMotor motor2(2, MOTOR12_1KHZ);
AF_DCMotor motor3(3, MOTOR34_1KHZ);
AF_DCMotor motor4(4, MOTOR34_1KHZ);
Servo myservo;
boolean goesForward=false;
int distance = 100;
int speedSet = 0;
void setup() {
myservo.attach(10);
myservo.write(115);
delay(2000);
distance = readPing();
delay(100);
distance = readPing();
delay(100);
distance = readPing();
delay(100);
distance = readPing();
delay(100);
}
void loop() {
int distanceR = 0;
int distanceL = 0;
delay(40);
if(distance<=15)
{
moveStop();
delay(100);
moveBackward();
delay(300);
moveStop();
delay(200);
distanceR = lookRight();
delay(200);
distanceL = lookLeft();
delay(200);
if(distanceR>=distanceL)
{
turnRight();
moveStop();
}else
{
turnLeft();
moveStop();
}
}else
{
moveForward();
}
distance = readPing();
}
int lookRight()
{
myservo.write(50);
delay(500);
int distance = readPing();
delay(100);
myservo.write(115);
return distance;
}
int lookLeft()
{
myservo.write(170);
delay(500);
int distance = readPing();
delay(100);
myservo.write(115);
return distance;
delay(100);
}
int readPing() {
delay(70);
int cm = sonar.ping_cm();
if(cm==0)
{
cm = 250;
}
return cm;
}
void moveStop() {
motor1.run(RELEASE);
motor2.run(RELEASE);
motor3.run(RELEASE);
motor4.run(RELEASE);
}
void moveForward() {
if(!goesForward)
{
goesForward=true;
motor1.run(FORWARD);
motor2.run(FORWARD);
motor3.run(FORWARD);
motor4.run(FORWARD);
for (speedSet = 0; speedSet < MAX_SPEED; speedSet +=2) // slowly bring the speed up to avoid loading down the batteries too quickly
{
motor1.setSpeed(speedSet);
motor2.setSpeed(speedSet);
motor3.setSpeed(speedSet);
motor4.setSpeed(speedSet);
delay(5);
}
}
}
void moveBackward() {
goesForward=false;
motor1.run(BACKWARD);
motor2.run(BACKWARD);
motor3.run(BACKWARD);
motor4.run(BACKWARD);
for (speedSet = 0; speedSet < MAX_SPEED; speedSet +=2) // slowly bring the speed up to avoid loading down the batteries too quickly
{
motor1.setSpeed(speedSet);
motor2.setSpeed(speedSet);
motor3.setSpeed(speedSet);
motor4.setSpeed(speedSet);
delay(5);
}
}
void turnRight() {
motor1.run(FORWARD);
motor2.run(FORWARD);
motor3.run(BACKWARD);
motor4.run(BACKWARD);
delay(500);
motor1.run(FORWARD);
motor2.run(FORWARD);
motor3.run(FORWARD);
motor4.run(FORWARD);
}
void turnLeft() {
motor1.run(BACKWARD);
motor2.run(BACKWARD);
motor3.run(FORWARD);
motor4.run(FORWARD);
delay(500);
motor1.run(FORWARD);
motor2.run(FORWARD);
motor3.run(FORWARD);
motor4.run(FORWARD);
}
We used 4 AA for the external power for the servo motor and 3.7 li-ion for the main power source of the arduino. We are not quite sure if what we did is correct since most tutorial doesn't have motor shield on them
How was this battery connected to the Arduino and what was its actual voltage at the time ?
The li-ion is connected through M+ and GND sector directly, when we tested it the battery was fully charged so it was probably 4.2v at most. The robot is functioning but the servo was not rotating so we decided to give it external power, we just don't know if we did it right.
I am confused by what you are saying. How is the Arduino board itself powered and at what voltage ?
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