Devlog #1 - breadboard prototype

I’ve been soldering a lot more recently thanks to starting a variety of electronics projects, and I’m starting to feel the need to get a fume extractor and some sort of air quality sensor to monitor my workspace.
After some consideration, I decided making my own fume extractor would be a fun project idea, and also a great way to use up some electronics components that I have lying around.

Components

To make this project, I ordered some cheap $6 12V cooling fans meant for PC setups. For the microcontroller, I’ll be using an ESP-01S, an ENS160+AHT21 (which can measure air quality and VOCs), and an I2C 0.91 inch OLED display, all components I already have. I spent some time desoldering the OLED display from an older PCB project to reuse it in this one.

Breadboarding

The ESP-01S is an incredibly small controller, with only two pins (GPIO0 and GPIO2) available as digital pins (apart from RX and TX, but I plan to use those for debugging). Since both the OLED and the ENS160+AHT21 are I2C components that communicate with Serial Data (SDA) and Serial Clock (SCL), theoretically these components could share GPIO0 and GPIO2 as SDA and SCL pins if they had different device addresses.
However, to be sure, I breadboarded and flashed a quick program to output the addresses and confirm that I had three separate, unique identifiers.

Now that I have this information, I’m ready to design the PCB next.