First tests stepper motor extrusion using 2 arduinos (simulating signal from ABB robot)

We managed to get the stepper motor working. We used an Arduino Mega to control the stepper motor with an A4988 Driver, and an Arduino Uno to emit a digital signal to the other arduino to simulate the signal it will end up receiving from the ABB Robot.

Two ways to control the extrusion: time or step. Time is not reliable at all. Controlling the steps is the proper way to achieve a reliable extrusion length.

Below, a table with extrusion measurements.

Resources:

http://howtomechatronics.com/tutorials/arduino/how-to-control-stepper-motor-with-a4988-driver-and-arduino/

https://learn.adafruit.com/thermistor/using-a-thermistor

http://randomdamon.blogspot.com/2015/12/diy-hot-end-arduino-pid-control.html

schematics stepper motor

IMG_0139

table 1st extruding test_Stepper motor

Here the code we used for both arduinos:

////////////////ARDUINO MEGA. Listen to a signal coming from the other arduino and start the stepper motor.

const int pinVal = 2; // transfer the info to the motor // reads the info from the other //arduino (in the future from the robot)
//const int caso = A0; // reads the length of the values from the robot
const int stepPin = 5;
const int dirPin = 4;
int caso = 0;
bool engine = true;
//bool activar = engine;
unsigned long duration;
unsigned long time;
int currentMillis = 0;
int previousMillis = 0;

void setup() {
// put your setup code here, to run once:

Serial.begin(9600);
pinMode(pinVal, INPUT);
pinMode(caso, OUTPUT);
pinMode(stepPin, OUTPUT);
pinMode(dirPin, OUTPUT);
digitalWrite(pinVal, HIGH);
engine = true;
}

void loop() {
//digitalWrite(stepPin, LOW);

duration = pulseIn(pinVal, HIGH);
// Serial.println("duration is: ");
// Serial.print(duration);

if(duration > 5000){
pulseIn(pinVal, HIGH);

casoA();
// Serial.print("Time: ");
// time = micros();
// Serial.println(time);
// delay(1000);

//retract();
pulseIn(pinVal, LOW);
// if(activar == true){
// digitalWrite(stepPin, HIGH);
// }else digitalWrite(stepPin, LOW);

}

else if(duration 1){
casoB();
// if(activar == true && stepPin == LOW){
// digitalWrite(stepPin, HIGH);
// }else digitalWrite(stepPin, LOW);
// Serial.println("holi");

// delay(3000);
// digitalWrite(stepPin, LOW);
}
// digitalWrite(stepPin, LOW);
else off();
}

void casoA(){
// pulseIn(pinVal, LOW);
if(engine == true){
// Serial.println("duration is: ");
// Serial.print(duration);
Serial.println("CASO A");
unsigned long currentMillis = millis();
for(int x = 0; x < 2400; x++) { // 200 steps at full driver step is 1 complete rotation
// duration = pulseIn(pinVal, HIGH);

digitalWrite(dirPin, LOW);
digitalWrite(stepPin, HIGH);
delayMicroseconds(5000);
digitalWrite(stepPin,LOW);
delayMicroseconds(5000);
}
int exTime = currentMillis - previousMillis;
Serial.println("extrusion time is: ");
Serial.print(exTime);
previousMillis = 0;
engine = false;

}

}

void casoB(){
Serial.println("CASO B");
digitalWrite(dirPin, LOW);
digitalWrite(stepPin, HIGH);
delayMicroseconds(500);
digitalWrite(stepPin,LOW);
delayMicroseconds(500);

}
void off(){
pulseIn(pinVal, LOW);
Serial.println("\nOFF");
digitalWrite(stepPin, LOW);
//digitalWrite(dirPin, LOW);
delay(5000);
}
void retract(){
Serial.println("retraction!!");
for(int x = 0; x <span id="mce_SELREST_start" style="overflow:hidden;line-height:0;"></span>&lt; 400; x++) {

digitalWrite(dirPin, HIGH);
digitalWrite(stepPin, HIGH);
delayMicroseconds(500);
digitalWrite(stepPin,LOW);
delayMicroseconds(500);
}
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////

ARDUINO UNO. This code reads the hot end and emits a signal

#include
// Analog output pin
#define outputPin 9
// thermistor analog pin
#define THERMISTORPIN A0
// how many samples to take and average
#define NUMSAMPLES 5
// how long between pid/sampling
#define SAMPLETIME 1000
//Define Variables we’ll be connecting to
double Setpoint, currentTemp, Output;
//Specify the links and initial tuning parameters
PID myPID(¤tTemp, &Output, &Setpoint,15,.3,0, DIRECT);

//////////////////////////////// FROM HERE BELOW SETTING TO SEND SIGNAL WHEN TEMPERATURE OK TO PRINT /////////////////
const int casoA = 3; // 10000 delay (speed of the robot) and rotate CW
const int casoB = 4; // 20000 delay and rotate CCW

int casos;
int vel = 0;
int dir = 1;
bool engine = true;
int val = 0;
int previousMillis = 0;
int currentMillis = 0;
long interval = 10000;
bool SENDSIGNAL = false;
////////////////////////////////////

void setup() {
Serial.begin(9600);
analogReference(EXTERNAL);
pinMode(outputPin, OUTPUT);

//initialize PID setpoint *C
Setpoint = 190;
//turn the PID on
myPID.SetMode(AUTOMATIC);
myPID.SetSampleTime(SAMPLETIME);
//pid Autotuner

pinMode(casoA, OUTPUT);
pinMode(casoB, OUTPUT);

}
void loop() {
if (Serial.available() > 0) {
// get incoming byte:
Setpoint = Serial.parseFloat();
}
uint8_t i;
double average = 0;
// take N samples in a row, with a slight delay
for (i = 0; i 2){
SENDSIGNAL = false;
digitalWrite(casoA, LOW);
}

}
/////////////////////////////////////////////////
// if(SENDSIGNAL == true){
// Serial.print(SENDSIGNAL);
//
// unsigned long currentMillis = millis();
// if(currentMillis – previousMillis interval){
// digitalWrite(casoA, LOW);
// }
// // else if(currentMillis – previousMillis > interval){
// // digitalWrite(casoA, LOW);
// // }
//
// //delay(20000);
// //analogWrite(casoA,255);
// //
// // digitalWrite(casoB, HIGH);
// // analogWrite(casoB, 100);
// previousMillis = 0;
// }

///////////////////////////////////////////////////
}

double inputToResistance(double input) {
// funtion to convert the input value to resistance
// the value of the ‘other’ resistor
double SERIESRESISTOR = 10000;
input = 1023 / input – 1;
return SERIESRESISTOR / input;
}
double resistanceToC(double resistance) {
// funtion to convert resistance to c
// temp/resistance for nominal
double THERMISTORNOMINAL = 118000;
double TEMPERATURENOMINAL = 25;
// beta coefficent
double BCOEFFICIENT = 3950;
double steinhart;
steinhart = resistance / THERMISTORNOMINAL; // (R/Ro)
steinhart = log(steinhart); // ln(R/Ro)
steinhart /= BCOEFFICIENT; // 1/B * ln(R/Ro)
steinhart += 1.0 / (TEMPERATURENOMINAL + 273.15); // + (1/To)
steinhart = 1.0 / steinhart; // Invert
steinhart -= 273.15; // convert to C
return steinhart;
}


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