Features
1. A reed switch module to detect the magnetic field. Different from Hall sensors which are generally used to measure the speed of intelligent vehicles and count assembly lines, reed switches are often used to detect whether there is a magnetic field.
2. Use a normally open reed switch.
3. Working voltage: 3.3-5V; PCB size: 2.0 x 2.0 cm.
4. Output digital signals.
5. With power light; a 3-pin anti-reverse cable included.

Features
1. USAGE - A tilt switch is to detect an inclination.
2. BIDIRECTIONAL CONDUCTION - Use a ball switch as bidirectional conduction.
3. ANTI-REVERSE PORT - Provides a firm connection.
4. INDICATORS - With an indicator for digital signal output. 
5. Working voltage: 3.3-5V; PCB size: 2.0 x 2.0 cm

For more information, please refer to http://wiki.sunfounder.cc/index.php?title=Tilt_Switch_Sensor_Module

Features
1. An infrared tracking sensor module that uses a TRT5000 sensor. The blue LED of TRT5000 is the emission tube and after electrified it emits infrared light invisible to human eye. The black part of the sensor is for receiving; the resistance of the resistor inside changes with the infrared light received.
2. The sensor TRT5000 is highly sensitive with reliable performance.
3. Utilize infrared to detect, high capacity of resisting disturbance.
4. Working voltage: 3-5V DC; PCB size: 1.4 x 3.5 cm.

Infrared proximity sensor made by Sharp. Part # GP2Y0A21YK has an analog output that varies from 3.1V at 10cm to 0.4V at 80cm. The sensor has a Japanese Solderless Terminal (JST) Connector. We recommend purchasing the related pigtail below or soldering wires directly to the back of the module.

This is the HC-SR04 ultrasonic ranging sensor. This economical sensor provides 2cm to 400cm of non-contact measurement functionality with a ranging accuracy that can reach up to 3mm. Each HC-SR04 module includes an ultrasonic transmitter, a receiver and a control circuit.

There are only four pins that you need to worry about on the HC-SR04: VCC (Power), Trig (Trigger), Echo (Receive), and GND (Ground). You will find this sensor very easy to set up and use for your next range-finding project!

Features
1. Support quick response; highly sensitive.
2. Provide a peak wavelength of 940nm.
3. With power light and signal output indicator and 3-pin anti-reverse cable.
4. PCB size: 2.0 x 2.0 cm.
5. Working voltage: 3.3-5V

Features
1. An infrared receiver module that uses a 1838b highly sensitive IR receiver.
2. Low cost, wide-angle, and long-distance receiving.
3. Output levels compatible with TTL and CMOS level, activated by low level.
4. With power light and indicator of digital signal output.
5. Working voltage: 3-5V DC; PCB size: 2.0 x 2.0 cm.

Features
1. A photoresistor module of which the resistance decreases with increasing incident light intensity.
2. Sensitive to ambient light conditions; so it is generally used to detect the light intensity in the surroundings, trigger MCU or relay module, etc.
3. Use a highly-sensitive photoresistor sensor.
4. With power light; a 3-pin anti-reverse cable included.
5. Working voltage: 3.3-5VDC; PCB size: 2.0 x 2.0 cm.

Features
1. A sound sensor module that can act as a microphone. The sensor receives sound waves and converts them into electrical signal, so it can detect the sound intensity in ambient environment.
2. Particularly sensitive to the intensity of ambient sound.
3. High precision, good universality, high cost performance.
4. Working voltage: 3-5V DC; PCB size: 2.0 x 2.0 cm.
5. 3-Pin anti-reverse cable included.

Features
1. An Obstacle Avoidance Sensor applies the infrared reflection principle to detect obstacles.
2. The detection distance of IR obstacle avoidance module is 3 ~ 30 cm.
3. Adjustable detection distance (by potentiometer on the module).
4. Working voltage: 3-5V DC; PCB size: 2.0 x 2.0 cm.
5. When there is an object in front which blocks and reflects the infrared light, the infrared receiver will receive signals and the indicator lights up; otherwise it stays off.