This is a simple device that measures ambient temperature and humidity and stores the readings on an SD card every five minutes. It is based on a DHT22 sensor and a PIC24FJ64GA102-I/SS microcontroller.

Power is supplied via a USB-C connector and a Li-Ion battery, which is charged by the integrated MCP73831 linear charger. The board also includes an accelerometer, allowing the display to rotate as needed - a rather unnecessary feature, but I had a few ADXL345 chips available. For the display, I used an inexpensive 1.8" ST7735 TFT module from AliExpress.

The supply voltage for the MCU and sensor is generated by a TPS631000 buck-boost converter.
The average current consumption is approximately 15 mA and has yet to be optimized.

The SD card library was generated using MCC in MPLAB. The application code was partially written with the help of AI.