GoKawiilDesigning and assembling my first PCB
Published: July 11, 2026
The beginning
About a couple months ago I purchased an Arduino Nano ESP32 dev board. I had this sudden itch and I wanted to play around with hardware. I don't really have much experience in this space, besides working on firmware for an IoT company over a decade ago, but I've written tons of software over the years. I was very surprised how quickly I was able to get the built-in LEDs to blink with Arduino IDE and some help from LLMs. After that I moved on to figure out how to build and flash firmware directly from the command line without having to deal with all these custom abstractions. I like operating from CLI. That was also somewhat easy and gave me confidence that I can go back to my normal tools (nvim) for working with code.
The devboard itself does not have much going on. Next was getting some peripherals so I ordered a small LCD and BME280 temperature/humidity sensor breakout boards. Both of these I was able to wire up to the ESP32 chip and get them to talk over the I2C protocol.
Figure 1: Playing around with Arduino Nano and random things attached to it via breadboard.
Naturally, we cannot continue assembling pre-existing modules for a variety of reasons. I think they are great for prototyping, but I like getting out of the prototyping phase as soon as possible and getting into a more "release" or "production" workflow. I was thinking maybe I should recreate the Arduino board with all these components hardwired so I can ditch the breadboard. That sounded great, but it felt a little bit ambitious. There's lots of components and it would make it hard for me to test everything. Instead, I decided to create the BME280 sensor module. This would let me get a feel for what it takes to design something starting with schematics and ending up with a custom PCB. In the picture above you can see the small brown board that I got from Amazon, that's a BME280 sensor board which only has a handful of components. If everything goes as planned I should be able to swap-in my custom board and everything should continue working as before. That was the plan.
Schematic and PCB design
There seem to be several tools available for schematic/pcb design. I needed something that's free and runs on Mac OS. Some people praise EasyEDA, others like KiCad. I didn't do much research on this topic, it seemed like either of them would fit the bill, but I picked KiCad since it's free GPL licensed software.
All sensors, chips and components come with what's called a datasheet. A datasheet is a technical document made available by the manufacturer describing how the component functions, at what temperatures it can operate, reflow (soldering) temperature curves, size and exact dimensions, example wiring and many other things depending on the component.
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