IOT system
Components |
Devices/Sensors → collect data
Connectivity → WiFi, Bluetooth, etc.
Data Processing → edge/cloud
Application → user interface |
Architecture Layers |
Perception → sensing (sensors, actuators) |
Sensors; Actuators; RFID tags and readers; Embedded devices; Microcontrollers |
Network → data transmission |
Routers; Gateways; Communication modules; Internet infrastructure |
Communication Technologies |
Wi-Fi; Bluetooth; ZigBee |
Protocols Used |
MQTT; CoAP; HTTP; AMQP |
Processing → storage, analytics |
Cloud, edge computing, databases |
Application → user services |
Sensors vs Actuators |
Sensors → input (temperature, light)
Actuators → output (motor, relay) |
IoT protocols
reliable and efficient communication |
data transfer, interoperability, low power usage, low latency and security |
Protocol Stack |
Link Layer: Physical communication (Wi-Fi, ZigBee) |
Network Layer: Addressing and routing (IPv6, 6LoWPAN) |
Transport Layer: Reliable or fast data transfer (TCP/UDP) |
Application Layer: IoT protocols (MQTT, CoAP, HTTP, AMQP) |
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Arduino
function - interface sensors + actuators; execute control logic; communicate with cloud + devices (data) |
microcontroller based; uses Wifi/ bluetooth |
setup() - initialize settings; executes once |
loop() - continuously; repeatedly |
GPIO - interact with external devices; input from sensors; output to actuators |
Arduino IDE - write, compile, and upload programs (sketches); syntax checking, library support, and serial monitor |
types of Arduino - 1. Arduino Uno (basic), 2. Mega 2560 (more I/O pins + memory), 3. Nano (compact), 4. MKR WiFi 1010 (WiFi) 5. Uno WiFi Rev2 (WiFi) |
Arduino shields - add-on boards; extend functionalityWi-Fi, Bluetooth, motor control, and sensor interfacing (without complex wiring) |
interface sensor with arduino |
VCC → 5V/3.3V
GND → GND
Output → Analog/Digital pin (e.g., A0 or D2) |
Connect sensor to Arduino → Configure pin → Read sensor data → Process and use data |
Data acquisition
Sensor → Arduino reads data → Processes values → Displays results |
Components Required
1. Arduino Uno / Nano
2. Temperature Sensor (LM35 / DHT11) or LDR
3. 16×2 LCD Display (or Serial Monitor)
4. Resistors and connecting wires
5. Breadboard
6. Power supply |
int sensorPin = A0;
float temperature;
void setup() {
Serial.begin(9600);
}
void loop() {
int sensorValue = analogRead(sensorPin);
temperature = sensorValue * 0.488;
Serial.print("Temperature: ");
Serial.print(temperature);
delay(1000);
}
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Arduino Toolchain
Toolchain = set of tools to write, compile, upload, debug programs |
Components
Arduino IDE → write code (sketch)
Editor → C/C++ code writing
Compiler → converts code → HEX file
Uploader → uploads to Arduino
Hardware → executes program |
Program Development Flow
Write code (setup(), loop()) → Compile (error checking) → Upload to board → Execute on hardware |
Debugging Methods
Serial Monitor → print values
Serial Plotter → graph output
LED indicators → check flow |
Importance
Simplifies embedded programming
Detects errors automatically
Enables quick upload
Supports libraries
Helps debugging
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Arduino I/O Concepts
Digital I/O
Operates in two states: HIGH (1), LOW (0)
Digital Input → binary signals from sensors
Digital Output → controls actuators (LED, relay, buzzer)
Functions: digitalRead(), digitalWrite() |
Analog I/O
Handles continuous signals (0–5V)
Analog Input → uses ADC to convert signal (0–1023)
Function: analogRead() |
Analog Output (PWM)
Simulates analog signal using PWM
Range: 0–255
Function: analogWrite() |
Interfacing in IoT
Sensors → input via digital/analog pins
Actuators → controlled via output pins
Flow: Sensor → Arduino → Processing → Actuator |
Challenges
Challenges in Arduino-based IoT Systems |
Voltage mismatch between devices
Limited GPIO pins
Signal noise and inaccurate readings
Power supply constraints
Timing and synchronization issues
Limited memory and processing capability
Communication failures (WiFi/Bluetooth)
Scalability issues for large systems
Debugging difficulties
Environmental effects on sensors
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Effectiveness of Arduino |
Comparison
Feature |
Arduino |
Raspberry Pi |
ESP32 / ESP8266 |
Ease of Use |
Very Easy |
Moderate |
Moderate |
Cost |
Low |
High |
Very Low |
Processing |
Low |
High |
Medium |
Connectivity |
External |
Built-in |
Built-in |
Power Consumption |
Low |
High |
Medium |
Real-Time |
Excellent |
Poor |
Good |
Scalability |
Limited |
High |
Moderate |
Memory Capacity |
Limited |
High |
Moderate |
Suitability |
Small- scale IoT, control systems |
Data- intensive IoT applications |
Wireless IoT nodes |
PART C
Arduino IoT Temp & Humidity System |
System Components
Arduino Uno
DHT11/DHT22 sensor
ESP8266 WiFi module
Power supply
Cloud platform (ThingSpeak/AWS) |
Block Flow
Sensor → Arduino → WiFi → Cloud → User |
Program{{nl |
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