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:
https://learn.adafruit.com/thermistor/using-a-thermistor
http://randomdamon.blogspot.com/2015/12/diy-hot-end-arduino-pid-control.html
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>< 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;
}
MULTI - RESOLUTION 