This tiny ESP32-C3 development board comes with an even tinier 0.42‑inch display

While searching AliExpress for good deals and new products, I came across the Aitver ESP32-C3 0.42-inch OLED, a tiny ESP32-C3-based development board that can be found under many names on AliExpress, designed for quick IoT prototypes, wearables, or display-based projects because of its small footprint and Arduino/MicroPython compatibility.

The board uses an ESP32-C3 instead of a more popular ESP32-S3 because it is designed for compact and wearable projects with much lower power consumption and lower cost. It's way less powerful than the ESP32-S3, but it has a 32-bit RISC-V core with 400 kB of static RAM and 4MB of SPI Flash, which is not shabby for a tiny MCU like this. Additionally, it has Wi-Fi 4 and Bluetooth 5.0 Low Energy (BLE) radios with an onboard ceremci chip antenna for connectivity.

The 0.42-inch OLED used on the board is driven by an SSD1306 controller with a special 72×40 pixel mapping, but the AliExpress page explicitly warns that the starting coordinate is 128×64. For power and programming, it has an onboard USB-C port along with a boot and reset button. There are thirteen usable GPIOs with UART, I2C, SPI, and ADC interfaces, and an onboard LED connected to GPIO8.

For programming, you can use the Arduino IDE or ESP-IDF, and there are various online tutorials available for the ESP32-C3-based boards. The Aitver ESP32-C3 0.42-inch OLED Development Board is sold for around US$4.99 on AliExpress. There are also other listings with a US$0.99 price tag, but all of those are part of the welcome offer, and it's possible you may not get it at that price.