I’ve spent quite some time trying to figure out whether or not I should post the source code for the soldering pen. It’s not like it’s particular secret or anything but I had a internal battle anyway. In the end I was convinced that it should indeed be open. That also means that you out there can spot errors and help on improving the code.
I don’t see myself as the perfect programmer so you will most likely find some typos and logical errors in there. I know for a fact that I need a watchdog and preferably also some feedback on the input voltage. right now I haven’t done that so USE THIS ON YOUR OWN RISK!
you know how it goes – your own stuff, your own safety. I live in europe so getting sued is not that common but anyway..
without further ado:
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#include <EEPROM.h> //Pins: #define REDLED 5 #define GREENLED 6 #define BLUELED 9 #define HEATER_OUT 10 #define STDBY_IN 7 #define BUTTONUP 11 #define BUTTONDOWN 12 #define SENSOR A2 //Opamp definitions #define ADC_TO_TEMP_GAIN 0.39 #define ADC_TO_TEMP_OFFSET 23.9 #define CNTRL_GAIN 10 #define DELAY_MAIN_LOOP 10 int pwm; int storedTemp; //temp stored in EEPROM int wantedTemp; int currentTemp; bool standby=1; //are we in standby? int brightness[3] = {0,0,0}; // how bright each LED (R,G,B) is int fadeAmount[3] = {1,1,1}; // this controls the speed of a fading pulse. Each color channel can have its own speed unsigned long setupTime =0; unsigned long setupLEDTime = 0; unsigned long previousUp = 0; //last UP press unsigned long previousDown = 0; //last DOWN press bool buttonDownPressed=0; bool buttonUpPressed=0; bool setupMode=0; void setup() { //set pin directions: pinMode(HEATER_OUT, OUTPUT); pinMode(REDLED, OUTPUT); pinMode(GREENLED, OUTPUT); pinMode(BLUELED, OUTPUT); pinMode(STDBY_IN, INPUT); pinMode(BUTTONUP, INPUT); pinMode(BUTTONDOWN, INPUT); pinMode(SENSOR, INPUT); pwm=(25*255)/100; digitalWrite(HEATER_OUT, LOW); //enable pullup digitalWrite(STDBY_IN, HIGH); digitalWrite(BUTTONUP, HIGH); digitalWrite(BUTTONDOWN, HIGH); //Get stored temperature from EEPROM. the value is in 10 degrees: 35 = 350degrees storedTemp = EEPROM.read(0); //read value at address 0 if(storedTemp > 45) //should also catch uninitialized memory { storedTemp = 35; //set the temp to a nice default value EEPROM.write(0,storedTemp); //save the value } wantedTemp = storedTemp*10; //load the wanted temperature } void displayTemp() //Show the current temperature { analogWrite(HEATER_OUT,0); // turn off! fadeOut(REDLED,0); fadeOut(GREENLED,1); fadeOut(BLUELED,2); delay(250); for(int i=0;i<storedTemp/10;i++) //for all 100's of degrees, show a red blink (300 degrees = 3 blinks) { analogWrite(REDLED,100); delay(500); analogWrite(REDLED,0); delay(500); } delay(500); //a small pause between the 100's and the 10's for(int i=0;i<storedTemp%10;i++) //show a blue blink for all the 10's of degrees (50 degrees = 5 blinks) { analogWrite(BLUELED,100); delay(500); analogWrite(BLUELED,0); delay(500); } } int getTemperature() //get the current temperature of the tip { analogWrite(HEATER_OUT, 0); //switch off heater delay(10); //wait a bit to let opamp and filter settle int adcValue = analogRead(SENSOR); //Get conversion value analogWrite(HEATER_OUT, pwm); //switch heater back to last value return round(((float) adcValue)*ADC_TO_TEMP_GAIN+ADC_TO_TEMP_OFFSET); //apply linear conversion to actual temperature } void readButtons(int debounceTime) { unsigned long currentMillis = millis(); //get current time if(digitalRead(BUTTONDOWN)==0) { if(previousDown==0) //if the button was not pressed before previousDown = currentMillis; //get the time the button was pressed down else { if(currentMillis-previousDown>=debounceTime) { //button press valid buttonDownPressed=1; previousDown=0; } } } else { previousDown=0; //clear the last time the buttons was pressed buttonDownPressed=0; } if(digitalRead(BUTTONUP)==0) { if(previousUp==0) //if the button was not pressed before previousUp = currentMillis; //get the time the button was pressed down else { if(currentMillis-previousUp>=debounceTime) { //button press valid buttonUpPressed=1; previousUp=0; if(!digitalRead(BUTTONDOWN)==0 && setupMode==0) displayTemp(); } } } else { previousUp=0; //clear the last time the buttons was pressed buttonUpPressed=0; } } void fadeOut(char LED, char index) { if(brightness[index]>0) { while(brightness[index]>2) { fadeAmount[index] = -abs(fadeAmount[index]); brightness[index] += fadeAmount[index]; analogWrite(LED,brightness[index]); delay(2); } analogWrite(LED,0); //turn the LED completely off brightness[index]=0; } } void indicateLED(char LED, int showTime) //indicate a button press. flash the LED for a short period and turn it off again { digitalWrite(LED,HIGH); delay(showTime); digitalWrite(LED,LOW); } void fade(char LED, char index) { if(brightness[index]<1) brightness[index]=1; analogWrite(LED,brightness[index]); // change the brightness for next time through the loop: brightness[index] += fadeAmount[index]; // reverse the direction of the fading at the ends of the fade: if (brightness[index] < 2 || brightness[index] > 100) fadeAmount[index] = -fadeAmount[index] ; } // the loop routine runs over and over again forever: void loop() { if(digitalRead(STDBY_IN)==0) //if the hall sensor is triggered { analogWrite(HEATER_OUT,0); // turn off! standby=1; } else standby=0; if(standby) //if we're in standby { analogWrite(HEATER_OUT,0); // turn off! fadeOut(REDLED,0); fadeOut(GREENLED,1); fade(BLUELED,2); delay(15); } else if(!standby && !setupMode) { fadeOut(BLUELED,2); //do the heating stuff here but only a single loop. //compute difference between target and actual temperature: int diff = wantedTemp-getTemperature(); pwm = diff*CNTRL_GAIN; //apply P controller: pwm = constrain(pwm,0,255); //limit pwm value to 0...255: analogWrite(HEATER_OUT, pwm); //set the PWM duty cycle if(diff>5) //we're not hot enough yet { digitalWrite(GREENLED,LOW); analogWrite(REDLED,pwm); brightness[0] = pwm; } else if(diff<-5) //we're too hot { analogWrite(HEATER_OUT,0); // turn off! digitalWrite(GREENLED,LOW); indicateLED(REDLED,5); delay(90); } else //we're inside the sweet spot { analogWrite(REDLED,0); fade(GREENLED,1); } delay(10); } //handle buttons here readButtons(1000); //read the buttons with a timeout of 1000ms, meaning that a press is not confirmed if it's shorter than 1000ms if(buttonDownPressed && buttonUpPressed) { setupMode=1; setupTime=millis(); } if(setupMode==1) { analogWrite(HEATER_OUT,0); // turn off! fadeOut(REDLED,0); fadeOut(GREENLED,1); fadeOut(BLUELED,2); delay(100); while(buttonDownPressed || buttonUpPressed) //wait for the user to release buttons before unlocking the setup features { readButtons(50); if (millis() - setupLEDTime >= 1000) //blink the green LED to show that we're in setup mode { setupLEDTime = millis(); indicateLED(GREENLED,5); } } while(millis()-setupTime<5000) //trap in this loop while we're setting up. Escape if no button is pressed within timely manner { readButtons(100); //read the buttons with 50ms debounce time if(buttonDownPressed) //turn temp down 10 degrees if button down is pressed { storedTemp--; setupTime = millis(); setupLEDTime=millis(); indicateLED(BLUELED,100); } if(buttonUpPressed) //turn temp up 10 degrees if button up is pressed { storedTemp++; setupTime = millis(); setupLEDTime=millis(); indicateLED(REDLED,100); } while(buttonUpPressed || buttonDownPressed) readButtons(50); if (millis() - setupLEDTime >= 1000) //blink the green LED to show that we're in setup mode { setupLEDTime = millis(); indicateLED(GREENLED,5); } } storedTemp = constrain(storedTemp,4,45); //constrain the temperature - not below 40 degrees and not above 450. don't damage the tip! setupMode=0; //exiting setup mode EEPROM.write(0,storedTemp); //store the temp in EEPROM wantedTemp = storedTemp*10; //set the wanted temperature now displayTemp(); //show the new temperature } } |