Adding Cold Welding Function to any Welder

• Cold spot weld function
• Most tig welders interface with a 5 pin foot controller 
  • 3 pins for potentiometer - analog signal telling how much amperage
  • 2 pin switch for initiating the arc
• Made a circuit to spoof the footswitch 
  • 555 timer to set the duty cycle
  • Monostable mode
  • Capacitively coupled to allow for single button presses
• Range: 1ms to 100ms