If you want to upgrade your soldering setup without spending a lot of money, then be sure to check out Angelo Casimiro’s DIY Hakko 907 station. 

This low-cost device features an Arduino Nano to read the iron temperature via an LM358 op-amp, and regulates power to the handle and tip under PWM control using an IRFZ44N MOSFET. A potentiometer is implemented as a variable temperature knob, with the actual and preset temperature displayed on a 16×2 LCD screen, while an LED indicates whether the heating element is active. 

Everything is encased in a nicely printed and painted enclosure, which forms a brilliant little station that one could be proud to use. Full build instructions can be found here, including the PCB, code, and print files.