Very small module based on the HTU21D digital temperature and humidity sensor with I²C interface

Small breakout board built around the tiny INMP441 omnidirectional MEMS microphone

Obstacle detector made up of an infrared transmitter and receiver

Proximity sensor made up of an LM393 voltage comparator chip, an infrared transmitter and receiver, a trimmer to set the sensitivity, a digital output (0 and 1) and two status LEDs for power and output signal

Compact laser receiver module designed to accurately detect the presence of a laser beam. With dimensions of 1.52 cm * 2.22 cm and powered at 5V, it provides a high logic output when hit by the laser beam and a low output when no beam is detected. Ideal for security, tracking and object-detection applications.

This compact module uses a LASER as the transmitter and a phototransistor as the receiver. The beam emitted by the transmitter is reflected by the surface in front of it and hits the lens of the receiver (the lens focuses the reflected light onto the phototransistor), turning the phototransistor on