I want to mod a Cheap orange Banggood DC Welder to control the welding time and current accurately from a microcontroller. Also i want to make it possible to create a spark from the microcontroller.
I can enable and disable the welder via the shutdown pin from a raspberry currently , so it is easier to create and tweak the necessary state machine, the plan is to start welding with an input from the main Button of the Tig torch. Then the raspberry would enable the welder pwm by pullling the shutdown pin low. A short time later the raspberry will enable a HF coil with a transistor and create a spark from the gun tip to the workpiece, lighting the arc. A fixed time later the raspberry will again shut down the PWM of the welder to end the arc.
One question that i have would be what would be a good sensor to sense the arc as being lit, otherwise it might be difficult to predict when exactly the arc lights up. I could imagine to measure the voltage on the Welder electrodes, but im worried that High voltage spikes might destroy the raspberry, another option would be to use a loop style current sensor , but im not sure how quickly it could measure a current that rises when the arc lights up.
I'll post updates and photos with progress,
I'm new to this forum and I wanted to post here to see if someone is interested in this project.