subroutine with if else does not work

Question

Everything in this code seems to work as expected except the subroutine speedcw at the bottom. It should change the time_delay variable.

#define ENA 2 //pin 2 on chip
#define in_A 0 //pin 0 on chip IN2
#define in_B 1 //pin 1 on chip IN1
#define in_C 3 //pin 3 on chip AUX
#define in_D 4 //pin 4 on chip AUX
byte PWM_PIN = 5; //pin 5 on chip
int pwm_value = 1500;
int time_delay = 7;
void setup() {
 pinMode(ENA, OUTPUT);
 pinMode(in_A, OUTPUT);
 pinMode(in_B, OUTPUT);
 pinMode(in_C, OUTPUT);
 pinMode(in_D, OUTPUT);
 pinMode(PWM_PIN, INPUT);
}
void step1(){
 //A+,B+
 digitalWrite(in_A, 1);
 digitalWrite(in_B, 1);
 delay(time_delay);
}
void step2(){
 //A+,B-
 digitalWrite(in_A, 1);
 digitalWrite(in_B, 0);
 delay(time_delay);
}
void step3(){
 //A-,B-
 digitalWrite(in_A, 0);
 digitalWrite(in_B, 0);
 delay(time_delay);
}
void step4(){
 //A-,B+
 digitalWrite(in_A, 0);
 digitalWrite(in_B, 1);
 delay(time_delay);
}
void clockwise(long st){
 long i = 0;
 while( i < st ){
 //step1
 step1();
 //step2
 step2();
 //step3
 step3();
 //step4
 step4();
 i++;
 }
}
void counter_clockwise(long st){
 long i = 0;
 while( i < st ){
 //step1
 step4();
 //step4
 step3();
 //step3
 step2();
 //step2
 step1();
 i++;
 }
}
void loop() {
 pwm_value = pulseIn(PWM_PIN, HIGH);
 time_delay = 7;
 while (pwm_value <= 1450) {//red LED
 pwm_value = pulseIn(PWM_PIN, HIGH);
 digitalWrite(ENA, 1);
 // digitalWrite(in_C, 1); //red LED
 // digitalWrite(in_D, 0); //green LED
 // time_delay = 1;
 speedcw();
 clockwise(2);
 }
 while (pwm_value >= 1550) {//green LED
 pwm_value = pulseIn(PWM_PIN, HIGH);
 digitalWrite(ENA, 1);
 // digitalWrite(in_C, 0); //red LED
 // digitalWrite(in_D, 1); //green LED
 time_delay = 1;
 // speedccw();
 counter_clockwise(2);
 }
 while ((pwm_value >= 1451)&&(pwm_value <= 1549)) {
 pwm_value = pulseIn(PWM_PIN, HIGH);
 digitalWrite(ENA, 0);
 digitalWrite(in_C, 0);
 digitalWrite(in_D, 0);
 }
}
void speedcw(){
 if (pwm_value <= 900){
 time_delay = 1;
 }
 else if (pwm_value <= 1000){
 time_delay = 2;
 }
 else if (pwm_value <= 1100){
 time_delay = 3;
 }
 else if (pwm_value <= 1200){
 time_delay = 4;
 }
 else if (pwm_value <= 1300){
 time_delay = 5;
 }
 else if (pwm_value <= 1400){
 time_delay = 6;
 }
}
void speedccw(){
}

• bigjosh: Are you sure that 'pwm_value <= 1450' is ever true? If not, then the code would just skip that while loop and not even call speedcw().
• benjamin nikkel: thank you, you were correct i made and error with the pwm i was feeding my code, 1300 was the lowest received. im new to the arduino.
• Greenonline: @bigjosh - you should post that as an answer

Answer 1

If ‘pwm_value’ gets to 1401 or higher and stays there, ‘time_delay’ never changes from its 7 value.

For broad applicability, I would remove the assigning of 7 to ‘pwm_value’ in ‘void loop()’ and let the ‘case else’ code makes a substantive change and sustains it until driven by a new ‘pwm_value.’ Put an ‘else’ value in for condition where ‘pwm_value’ is 1401 or more (like 7, if that is what you intend.)