An ESP32 Board Smaller Than a Dime

Whenever someone claims to have created the world’s smallest, fastest, or anything-else-est electronic gadget, you should probably take it with a grain of salt until you see some solid proof. Software engineer Pegor Karoglanian doesn’t make any such claims about the f32 microcontroller development board that he recently designed, but if he did call it the world’s smallest, I might believe it. It would certainly be hard to create a complete ESP32 development board any smaller than this one that makes a dime look large.

To keep the footprint as small as possible, the PCB is mounted directly on top of a USB-C connector. The PCB itself is populated with a bare minimum of components — an ESP32-C3 chip, and necessary supporting components like capacitors and resistors. Only a single GPIO pin was exposed, which doesn’t allow for much interaction with external devices. However, Karoglanian doesn’t see this as a problem, as the board was designed primarily for Wi-Fi- or web-based applications.

To demonstrate the f32 in action, a simple web app was developed and hosted on the board. After loading the page in a web browser, users can flash the onboard LED, scan for nearby Wi-Fi networks, and test out other simple tasks that show what the f32 can do. Naturally, you would want to flash some more useful firmware to the board if you had your own f32. Fortunately, that is just as simple as with any other ESP32 board — simply connect the USB port to a computer, and use the standard Espressif development toolchain.

Should you want a super small ESP32 board of your own, you are in luck. Karoglanian has open-sourced the entire design — hardware and firmware — under an MIT license, and you can snag everything from GitHub. There are also instructions for assembling the board and flashing it with firmware. If a hot plate is not in your vocabulary, Karoglanian also suggests an assembly service where you can get the boards for a few bucks each.