Smart refrigerator magnet

This project aims to create a thin, lightweight smart screen that can be attached to a refrigerator, hence the name "Smart Refrigerator Magnet."

The project utilizes the ESP32-S3-WROOM-1-N16R8 module. Compared to the ESP8266 and ESP32, the ESP32-S3 module offers a large number of configurable I/Os, ensuring the project's scalability.

This project uses the CH334R USB HUB chip, combining USB OTG and serial port connections into a single USB Type-C interface. If only one of these is needed, do not solder the CH334R and its peripheral circuitry. Instead, solder 0Ω resistors on R21 and R22 to directly enable USB OTG functionality, or solder 0Ω resistors on R24 and R30 to directly enable UART serial port functionality.

Available peripherals include: an AHT20 thermometer and hygrometer, an MLT-5020 buzzer, a TF card slot, five programmable buttons (one of which is IO0, used for programming options), and an EN button.

This project uses the TP4056 as the lithium battery charge/discharge management chip and includes a power switching circuit.

Additionally, it features a 24-pin e-ink driver interface, compatible with most e-ink screens using 24-pin FPC cables. This project uses the Dalian Jiaxian GDEY042Z98 screen, which does not support [GxEPD2](https://github.com/ZinggJM/GxEPD2). To use GxEPD2, it can be configured as a GDEY042T81 for dual-color (black and white) driving. Alternatively, [EPaperDrive](https://github.com/HalfSweetStudio/EPaperDrive) can be used to directly drive the GDEY042Z98. Using other screens of the same size is recommended.

Cable installation:

![1726391823022.jpg]
Driver effect:

![1726391823031.jpg]
The firmware is still under debugging, but it can currently drive e-ink screens. It is easy to light up the screen by configuring the pins of various Arduino driver examples. PlatformIO development is more recommended.