The Digital Display Control Module for HC-SR04 is a compact, plug-and-play board that displays ultrasonic distance readings on a 3-digit LED display. It supports 3–400 cm measurement range and 9600 bps serial output, making it ideal for sensor testing, robotics debugging, and DIY distance measurement projects.

The Passive Buzzer Module is a compact audio module that uses PWM signals to generate different tones, melodies, and alarm sounds. It supports 3.3V–5V operation with an Active LOW trigger and a 1.5kHz–2.5kHz tone range. Ideal for Arduino, ESP32, Raspberry Pi, robotics, alarms, and DIY electronics projects.

The WT588D-16P Audio Player Module is a versatile voice playback module with 16M-bit (2MB) memory for storing WAV audio, voice prompts, and sound effects. It supports Key, Matrix, and 3-wire UART control, with 2.8V–5.5V operation and direct connection to a 0.5W/8Ω speaker. Ideal for robotics, smart home, security alarms, automotive warnings, toys, and Arduino/Raspberry Pi projects.

The 300W 10A DC-DC Step-Down Buck Converter Module efficiently converts 6V–40V DC input to an adjustable 1.2V–36V output with up to 10A current and 95% efficiency. It features a large heatsink and short-circuit protection, making it ideal for battery charging, high-power LEDs, solar systems, motor control, automotive applications, and DIY power supplies.