The DS1307 RTC Module is a reliable real-time clock module for accurate time and date tracking in Arduino, ESP32, Raspberry Pi, STM32, and other embedded projects. It uses the I²C interface, includes an AT24C32 4KB EEPROM for data storage, and provides a 1Hz output signal for timing applications. A CR2032 backup battery holder maintains time during power loss; the battery is not included.

The X9C104 100K Digital Potentiometer Module is a compact digitally controlled variable resistor with 100 selectable resistance steps across a total range of 100kΩ. It uses CS, U/D, and INC control inputs for electronic wiper adjustment and operates from a typical 5V supply. Ideal for programmable voltage dividers, sensor calibration, analog signal adjustment, digital volume control, and Arduino or microcontroller-based projects.

The DY-SV17F MP3 Player Module is a compact audio playback module with 32Mbit (4MB) Flash memory and an integrated 5W Class-D amplifier for driving 4Ω or higher speakers. It supports MP3 and WAV files, USB file uploading, and serial control at 9600 baud for playback, pause, volume, and track selection. With a 23 × 26mm compact design, it is ideal for Arduino, ESP32, robotics, voice notifications, alarms, toys, and embedded audio projects.