The article uses a logic level mosfet (IRLI640), while you used a fet (IRF540) that can't be fully turned 'on' with Arduino's 5volt logic.
Details matter.
Leo..
The article uses a logic level mosfet (IRLI640), while you used a fet (IRF540) that can't be fully turned 'on' with Arduino's 5volt logic.
Details matter.
Leo..