Finally I've made a working battery based portable soldering iron. This one can melt solder in under 10 seconds, which is amazing. The soldering iron weighs just above 100 grams, is comfortable to use, it can reach more than 300 degrees, it's very fast, we can recharge it with a USB connector since we have a protection IC inside on the PCB and on the screen, we can see the battery level, the internal resistance of the iron tip and we can set the heating time and maximum power. On the PCB we have a current sensor so we can measure the current and with that the power, we have an amplifier to measure the low resistance of the tip, and we have a MOSFET to control the power that is going to the tip.
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.
