In IoT, [Arduino](https://www.ampheo.com/c/development-board-arduino) is usually the “brain + glue” that connects [sensors](https://www.ampheo.com/c/sensors) and [actuators](https://www.onzuu.com/category/electric-actuators-cylinders) to the internet or to a gateway.


Think of it like this:

**IoT = (things) + (connectivity) + (cloud/app)**
Arduino is the small, cheap computer that lives inside the “thing”.

**1. What role does Arduino play in IoT?**

In most IoT projects an Arduino board:

**1. Reads data from sensors**

Temperature, humidity, light, motion, gas, current, GPS, etc.

**2. Controls actuators**

[Relays](https://www.onzuu.com/category/relays), [motors](https://www.onzuu.com/category/motors-actuators-solenoids-and-drivers), LEDs, valves, servos, [buzzers](https://www.onzuu.com/category/alarms-buzzers-and-sirens)…

**3. Handles local logic**

Thresholds, timers, simple automation (“if motion and it’s dark → turn on light”).

**4. Sends or receives data over a network**

* Directly (if it has Wi-Fi/Ethernet/cellular), or
* Indirectly via a gateway (e.g., Arduino → [Raspberry Pi](https://www.ampheo.com/c/raspberry-pi/raspberry-pi-boards) → cloud).

So in an IoT system, Arduino is often the edge device / node / endpoint.

**2. Typical Arduino-based IoT setup**
**A. Arduino with built-in connectivity**

Boards like:

* [Arduino Uno R4 WiFi](https://www.ampheo.com/product/abx00087-25542584)
* [Arduino Nano 33 IoT](https://www.ampheo.com/product/abx00027-25542615)
* ESP32-based “Arduino-compatible” boards

These can:

* Connect to Wi-Fi
* Use HTTP/MQTT to talk to a cloud server or broker
* Send sensor data to dashboards (ThingsBoard, Home Assistant, custom API, etc.)

Example idea:

Room sensor node: Arduino board + [DHT22](https://www.ampheo.com/product/part-dht22-26872164) + Wi-Fi → sends temperature/humidity every 30 seconds to an online API or home server.

**B. Arduino as a “sensor node” behind a gateway**

If the Arduino has no direct internet, it can:

Send data by UART/I²C/SPI/RS-485/BLE/LoRa to a gateway:

* Raspberry Pi
* Industrial controller
* Another Arduino with Wi-Fi

The gateway then uploads to the cloud.
So [Arduino](https://www.ampheoelec.de/c/development-board-arduino) is just the local hardware interface and brain.

**3. Why Arduino is popular in IoT**

* Easy to program (Arduino IDE, large community, tons of examples).
* Huge ecosystem of shields and modules:
* Wi-Fi/Ethernet shields
* GSM/4G shields
* Sensor breakout boards
* Low cost → good for prototyping and small deployments.
* Works well as a teaching and prototyping platform before moving to a custom PCB or more powerful MCU.

**4. How people usually describe Arduino “in IoT”**

If you need a one-sentence answer:

In IoT, Arduino is a [microcontroller](https://www.ampheo.com/c/microcontrollers) platform used as the edge device that reads sensors, controls actuators, and communicates with servers or cloud services over the network.