Spot welder with pulse control

Here's my spot welder designed around a high power transformer from a microwave.
I've took a lot of inspiration from a similar project from Jim Conner:
https://www.thingiverse.com/thing:2429361

But I've created both the model and the code from scratch.

###BOM with the pieces I've used (affiliate links):
* Nokia LCD: [link](http://s.click.aliexpress.com/e/jcExxdA)
* Encoder: [link](http://s.click.aliexpress.com/e/b7qymdI0)
* IEC Socket: [link](http://s.click.aliexpress.com/e/bjmNUeFW)