Smart temperature control for a cheap Soldering iron

I recently bought a less than 5 Euros cheap Soldering Iron which I decided to make smart by adding a control circuit to it.

The project requires the following components

1. Soldering Iron
2. Thermistor 10k PTC
3. OLED screen
4. Any microcontroller (I used esp32-s2 / Wemos S2 mini dev board)
5. Solid State Relay (SSR)
6. Resistors

The project had 3 main stages

1. Getting the thermistor ready to read the temperature
2. Getting an OLED screen to display the temperature
3. Driving relay to control temperature.

Budget

The total cost for the project was

1. Soldering Iron – 3.5 Euro
2. Thermistor 10k PTC – 1 Euro
3. OLED screen – 3.5 Euro
4. esp32-s2 / Wemos S2 mini dev board – 4 Euro
5. Solid State Relay (SSR) – 1.5 Euro
6. Resistors and other components – /

The total budget came to 13.5 Euros, which is cheap. 😉