My Upgraded Design

Published March 2, 2019

DIY Spotwelder - Part 2

I want to make a spot welder for battery packs or other stuff that cannot be soldered.

IntermediateWork in progress3,690

Things used in this project

Hardware components

Arduino Micro

Adafruit RGB Backlight LCD - 16x2

Software apps and online services

Arduino IDE

Hand tools and fabrication machines

Soldering iron (generic)

Story

WARNING! This project doesn't work. To know why, please go to part 3 (https://create.arduino.cc/projecthub/Westpol/diy-spot-welder-part-3-700923)

My Upgraded Design

I've thought about the first design of my spotwelder (https://create.arduino.cc/projecthub/Westpol/diy-cd-spot-welder-part-1-b60f05) and changed everything. The power supply is now a 5200mAh Li-Po battery with a discharge rate of 45c, the Mosfets are 20 130W ones and beside frome the pulse time, there is also the energy shown in joule. I also put two caps at the 5V pin of the Arduino to power the chip, because if you short the battery contacts the voltage of the battery will drop to almost nothing. In part 3, I will also clean up the sketch and with the help of a voltage divider to measure the voltage of the battery and some maths, the energy will be more accurate.

ToRebuildTheProjectByYourself

When you want to rebuild this project by yourself, you should be familiar with the basics of electronics, because if you do something wrong, it can kill your battery or the other components used in this project. Also the system isn't tested yet, so if you are not sure that it will work, wait until I upload part 3 where I'll test it.

TheSafety

The whole design isn't really save. I don't have any fuse installed and the high power traces are close to each other, so you should have an eye on it while working.

Code

int power = 1920;       // power of the battery in Watts
int MOSFETpin = 3;
int piezopin = 13;

int footswitchorbutton = 2;

int dlay = 0;
unsigned long timetilnext;
unsigned long locksec;
int oneafterlocked;
int prevdlay;
int prevlock;
int joule;

void setup() {
  pinMode(MOSFETpin,OUTPUT);
  pinMode(footswitchorbutton,INPUT_PULLUP);
  pinMode(A0,INPUT);
  Serial.begin(9600);
  timetilnext = millis();
  locksec = 0;
}

void loop() {
  
  if(millis() <= timetilnext){
    locksec = (timetilnext-millis())/1000;
    if(locksec != prevlock){
    Serial.print("locked for:");
    Serial.print(locksec);
    Serial.println("s");
    prevlock = locksec;
    }
    oneafterlocked = 1;
  }
  
  
  dlay = map(analogRead(A0),0,1023,1,15);
  dlay = dlay*10;
  
  if(millis() >= timetilnext){

  if(dlay != prevdlay || oneafterlocked == 1){
  joule = dlay/.1000*power/10000;
  Serial.print("Pulse:");
  Serial.print(dlay);
  Serial.println("ms");
  Serial.print("Energy:");
  Serial.print(joule);
  Serial.println("J");
  oneafterlocked = 0;
  prevdlay = dlay;
  }
  if(digitalRead(footswitchorbutton) == LOW){
    tone(piezopin,1000);
    delay(500);
    noTone(piezopin);
    delay(500);
    tone(piezopin,1000);
    delay(500);
    noTone(piezopin);
    delay(500);
    tone(piezopin,1000);
    delay(500);
    noTone(piezopin);
    delay(500);
    tone(piezopin,2000);
    delay(1000);
    noTone(piezopin);
    delay(500);
    digitalWrite(MOSFETpin,HIGH);
    delay(dlay);
    digitalWrite(MOSFETpin,LOW);
    timetilnext = 5000+millis();
  }
  }
  
}

#include <LiquidCrystal.h>

int power = 1920;       // power of the battery in Watts
int MOSFETpin = 3;
int piezopin = 13;
int lightpin = 4;
int footswitchorbutton = 2;

int dlay = 0;
unsigned long timetilnext;
unsigned long locksec;
int oneafterlocked;
int prevdlay;
int prevlock;
int joule;

const int rs = 8, en = 7, d4 = 9, d5 = 10, d6 = 11, d7 = 12;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

void setup() {
  pinMode(MOSFETpin,OUTPUT);
  pinMode(footswitchorbutton,INPUT_PULLUP);
  pinMode(A0,INPUT);
  pinMode(lightpin,OUTPUT);
  digitalWrite(lightpin,HIGH);
  timetilnext = millis();
  locksec = 0;
  lcd.begin(16,2);
  lcd.clear();
  
}

void loop() {
  
  if(millis() <= timetilnext){
    locksec = (timetilnext-millis())/1000;
    if(locksec != prevlock){
    lcd.clear();
    lcd.setCursor(2,0);
    lcd.print("locked for:");
    lcd.setCursor(7,1);
    lcd.print(locksec);
    lcd.print("s");
    prevlock = locksec;
    }
    oneafterlocked = 1;
  }
  
  
  dlay = map(analogRead(A0),0,1023,1,15);
  dlay = dlay*10;
  
  if(millis() >= timetilnext){

  if(dlay != prevdlay || oneafterlocked == 1){
  joule = dlay/.1000*power/10000;
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Pulse:");
  lcd.print(dlay);
  lcd.print("ms");
  lcd.setCursor(0,1);
  lcd.print("Energy:");
  lcd.print(joule);
  lcd.print("J");
  oneafterlocked = 0;
  prevdlay = dlay;
  }
  if(digitalRead(footswitchorbutton) == LOW){
    tone(piezopin,1000);
    delay(500);
    noTone(piezopin);
    delay(500);
    tone(piezopin,1000);
    delay(500);
    noTone(piezopin);
    delay(500);
    tone(piezopin,1000);
    delay(500);
    noTone(piezopin);
    delay(500);
    tone(piezopin,2000);
    delay(1000);
    noTone(piezopin);
    delay(500);
    digitalWrite(MOSFETpin,HIGH);
    delay(dlay);
    digitalWrite(MOSFETpin,LOW);
    timetilnext = 5000+millis();
  }
  }
  
}

Credits

Westpol

8 projects • 22 followers

DIY Spotwelder - Part 2

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

My Upgraded Design

Schematics

The scematic

The scematic as PDF

Code

CD_spot_welder_Serial.ino

LCD Spot Welder

Credits

Westpol

Comments

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DIY Spotwelder - Part 2

DIY Spotwelder - Part 2

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

My Upgraded Design

Schematics

The scematic

The scematic as PDF

Code

CD_spot_welder_Serial.ino

LCD Spot Welder

Credits

Westpol

Comments

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