Sensors & Modules (temperature, humidity, cameras, NFC, RFID)

Flynn · Sep 9, 2025

Sensors & Modules (Temperature, Humidity, Cameras, NFC, RFID)

One of the Raspberry Pi’s greatest strengths is its ability to interface with sensors and modules. By connecting directly to the GPIO pins (or via I²C, SPI, or UART), the Pi can collect data, control systems, and interact with the physical world. From environmental monitoring to access control, sensors and modules turn Raspberry Pi into a true IoT powerhouse.

1. Temperature Sensors

Popular Options:

DS18B20 – A waterproof digital temperature sensor that communicates via 1-Wire protocol.
DHT11 / DHT22 – Measure both temperature and humidity; DHT22 offers higher accuracy.
BME280 / BME680 – High-precision sensors that measure temperature, humidity, and air pressure (BME680 also detects VOCs).

Applications:

Smart thermostats.
Greenhouse climate control.
Weather stations.
Food storage monitoring.

2. Humidity Sensors

Humidity often pairs with temperature monitoring.

DHT22 / AM2302 – Most common low-cost digital humidity sensor.
BME280 – Highly accurate for long-term projects.
Si7021 – Used in professional IoT kits.

Use Cases:

Detect high humidity in basements or greenhouses.
Trigger dehumidifiers or fans automatically.
Integrate into HVAC systems for smart homes.

3. Cameras & Vision Modules

The Raspberry Pi Camera Module is one of the most powerful add-ons.

Options:

Camera Module 3 – 12MP with autofocus and HDR.
High-Quality Camera – Interchangeable lenses for photography/videography.
NoIR Camera – Infrared-sensitive, useful for night vision and plant monitoring.
Third-Party USB Webcams – Plug-and-play with Pi OS.

Applications:

Security systems with motion detection.
Time-lapse or slow-motion video.
AI projects with object or face recognition.
Wildlife observation and astrophotography.

4. NFC (Near Field Communication)

NFC modules let the Pi read and emulate contactless cards or tags.

Modules:

PN532 NFC Module – Popular, supports card emulation and peer-to-peer.
RC522 RFID/NFC – Budget-friendly module often used in access control.

Applications:

Contactless door locks.
Payment prototypes.
Smart inventory systems.
Interactive museum or event badges.

5. RFID (Radio Frequency Identification)

RFID overlaps with NFC but typically works at longer ranges (125 kHz / 13.56 MHz).

Modules:

RC522 – Widely used, supports RFID cards, tags, and key fobs.
125kHz RFID Readers – Used for industrial or livestock tracking.

Applications:

Employee ID scanners.
Pet/livestock tracking.
Library check-in/check-out systems.
Automated tool or equipment tracking.

6. Other Useful Modules

Motion Sensors (PIR) – Trigger alarms, lights, or cameras when movement is detected.
Gas Sensors (MQ-series) – Detect smoke, CO, CO₂, and VOCs.
Ultrasonic Distance Sensors (HC-SR04) – Great for robotics obstacle detection.
Accelerometers & Gyroscopes (MPU6050) – Measure tilt, vibration, and movement.
Relay Modules – Control AC appliances like pumps, fans, or lights.

7. Integrating Sensors with Raspberry Pi

Most sensors use one of these communication protocols:

GPIO (Digital On/Off) – Simple devices like PIR motion sensors.
I²C – Multi-sensor modules like BME280.
SPI – High-speed devices like RFID readers.
UART – Serial devices like GPS or particulate matter sensors.

Python libraries (gpiozero, Adafruit_Blinka, smbus2) make it straightforward to read sensor data.

Example (reading DHT22 with Python):

import adafruit_dht import board dht = adafruit_dht.DHT22(board.D4) temperature = dht.temperature humidity = dht.humidity print(f"Temp: {temperature:.1f}°C, Humidity: {humidity:.1f}%")

8. Project Ideas with Sensors & Modules

Smart Weather Station – Combine temperature, humidity, and barometric sensors.
Access Control System – RFID/NFC with door relays.
Greenhouse Monitor – Camera, soil, and humidity sensors feeding data to a dashboard.
Smart Security System – Motion + camera + RFID for safe entry.
Wildlife Camera Trap – PIR motion triggers camera to capture animals.

Conclusion

Raspberry Pi’s true power comes alive when paired with sensors and modules. With just a handful of inexpensive components, you can measure temperature, detect motion, capture images, or even build an NFC-based access system. These building blocks let hobbyists, educators, and professionals turn the Pi into a bridge between the digital and physical world, unlocking endless project possibilities.

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Sensors & Modules

Sensors & Modules (temperature, humidity, cameras, NFC, RFID)