My DIY spot welder

Dear Friends,

Today, I just finished my spot welder that my friend requested me to build. The spot welder has two main components - the on off timer and the microwave transformer.

The on-off timer

The timer is built with arduino pro mini. Other main components include

1. oled
2. 5V rectifier
3. 12 V relay
4. rotary encoder

The photo of the timer is as follow.

Rotary encoder is used to adjust and set the on-time of the relay. The set time is shown on the oled. The Arduino code for the pro mini was uploaded to my github at https://github.com/princekham/projects/blob/main/spot_welder.ino.

The transformer

Old microwave transformer was used. The primary coil was kept and the secondary coil was replaced with 7044 wire.

The result

I tested with 800ms on time and the result was pretty good. I am happy with the result.

Challenges

• I could not find the old microwave oven at first. It took some time to get one.
• I felt doubtful that I would be able to build one and that hindered my work progress. I had to motivate and push myself to finish the project.

I will hand over this to my friend tomorrow. I didn't get into details on how I built it because the wire connection details were written in the Arduino programme I provided in the GitHub link above. If you have questions, please leave them in the comment section.

Thank you for reading my post. Have a nice day!

@princekham
9th Feb 2022
Myanmar