Espresso machine 'Rancilio Silvia' PID upgrade

When i got 2015 my new espresso machine I had quite some problems with the fluctuating temperature of the boiler.

So I decided to replace the bimetal thermostat with a PID controller.

I installed the controller in an external plastic box, so I didnt had to cut any holes in the machine (just in case I want to sell the machine).

Second modification was adding a cheap LED lightsource.