# Lesson 16 · Create Helper Functions For Each Motor

Suggested Time: 30-45 minutes

## Lesson Overview

I show you how to simplify your move motor code using helper functions. I also demo how you would try to pick something up with your robot arm using code!

## Sample Code

/*
Challenge #1: Create individual move functions to simplify code
Challenge #2: Experiment with picking up an object
*/

#include <Servo.h>

#define CLAW_OPEN 120
#define CLAW_CLOSE 5

#define BASE_MAX 180
#define BASE_MIN 0

#define TILT_MAX 180
#define TILT_MIN 120

#define EXTEND_MAX 150
#define EXTEND_MIN 75

//- servos move half a circle 0-180 degrees.
Servo baseMotor;
Servo tiltMotor;
Servo extendMotor;
Servo clawMotor;

//- runs only once when you turn on
void setup() {
baseMotor.attach(6);
tiltMotor.attach(9);
extendMotor.attach(10);
clawMotor.attach(11);

home();

delay(1000);

}

void home() {
tiltMotor.write(90);
baseMotor.write(90);
extendMotor.write(90);
clawMotor.write(90);
}

void moveMotor(Servo motor, int target, int min, int max) {

//- figure out if we need to move up or down

//- if myCurrentAngle is > target, go down
if (myCurrentAngle > target) {
moveAngleDown(target,motor,min,max);
}

//- if myCurrentAngle is < target, go up
if (myCurrentAngle < target) {
moveAngleUp(target,motor,min,max);
}

}

void moveAngleUp(int target, Servo motor, int min, int max) {

while (angle <= target) {

if (angle <= max) {

//-do this code
motor.write(angle);
delay(100);

angle = angle + 5;
}
else {
break;
}

}

}

void moveAngleDown(int target, Servo motor, int min, int max) {

while (angle >= target) {

if (angle >= min) {

motor.write(angle);
delay(100);

angle = angle - 5;
}
else {
break;
}

}
}

void moveClaw(int target) {
moveMotor(clawMotor,target,CLAW_CLOSE, CLAW_OPEN);
}

void moveBase(int target) {
moveMotor(baseMotor,target, BASE_MIN, BASE_MAX);
}

void moveTilt(int target) {
moveMotor(tiltMotor,target,TILT_MIN, TILT_MAX);
}

void moveExtend(int target) {
moveMotor(extendMotor,target,EXTEND_MIN, EXTEND_MAX);
}

//- runs forever in a loop after setup
void loop() {

moveClaw(180);
delay(1000);
moveExtend(160);
delay(1000);
moveClaw(0);
delay(1000);
moveTilt(160);
delay(1000);
moveExtend(40);

while (1==1) {
//-do nothing
}

}