So for the components we need, of course the PCB which in my case, I’ve made it with PCBWAY. The MOSFET, the ATmega328 microcontroller together with the crystal oscillator, the SMD resistors and capacitors which are all in a 0603 package, the small SMD buzzer, some LEDs, the USB connector, the LM358 amplifier, the small OLED screen and the AMS712 current sensor. Along these components we also need some clips for the battery connection for positive and negative. The entire package cost me just 1 dollar. As for the tip, I’ve ordered a few which are marked as 15W. And to add the iron tip, we need a screw socket which also cost me just a few cents. Like this we can screw or unscrew the tip whenever we want.