MDM331AID/Experiment 8 - Revision history

CogWikiEditor: /* ESP32 Code */

2026-10-08T10:17:37Z

ESP32 Code

← Older revision		Revision as of 10:17, 8 October 2026
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	<pre>		<pre>
	// © 2026, Cognifront. Member of The IoT Kits Family.		// © 2026, Cognifront. Member of The IoT Kits Family.
	//~~Experiment 6:~~ Data Logging Using ESP32 and ~~Excel (~~Cloud ~~Communication)~~		// DHT11 Temperature Data Logging Using ESP32 and Cognifront Cloud

	#include "cogcloudesp.h"		#include "cogcloudesp.h"
			#include <DHT.h>

	~~//int cogLed = 15;~~		#define DHT_PIN 4
	~~const int lm35_pin = 34;~~		#define DHT_TYPE DHT11

	~~String ssid = "********"~~; ~~// wifi/hotspot name~~		DHT dht(DHT_PIN, DHT_TYPE);
	~~String pass = "********"; // wifi/hotspot password 2.4 hz band only~~

	String ~~apikey~~ = "~~YOUR_API_KEY_HERE~~"; // ~~API key from app. Keep the~~ "" ~~(quotes)~~		String ssid = "********"; // Wi-Fi / hotspot name
			String pass = "********"; // Wi-Fi / hotspot password

			String apikey = "YOUR_API_KEY_HERE"; // API key from Cognifront Cloud

	void setup ()		void setup()
	{		{
	~~// pinMode~~ (~~cogLed,OUTPUT);~~		Serial.begin(115200);
	~~pinMode (lm35_pin, INPUT~~);

	~~Serial~~.begin(~~115200);~~		dht.begin();
	~~while (!Serial)~~
	~~delay(100);~~
	~~cogInitCloud (ssid,pass,apikey~~);

	// ~~cogBindPin~~ (~~cogLed~~, "~~LED~~");		// Initialize Cognifront Cloud
			cogInitCloud(ssid, pass, apikey);

			Serial.println("DHT11 Temperature Monitoring Started");
	}		}

	void loop ()		void loop()
	{		{
	cogAppLoop();		// Handle cloud communication
			cogAppLoop();

			// Read temperature in Celsius
			float temperature = dht.readTemperature();

			// Check for sensor reading failure
			if (isnan(temperature))
			{
			Serial.println("Failed to read temperature from DHT11");
			delay(2000);
			return;
			}

	~~int voltage_mv = analogReadMilliVolts~~(~~lm35_pin~~);		// Display temperature on Serial Monitor
	~~float temp_val = voltage_mv / 10~~.0; ~~// LM35 = 10 mV per~~ °C		Serial.print("Temperature: ");
			Serial.print(temperature);
			Serial.println(" °C");

	// Send ~~value~~ to ~~cloud~~		// Send temperature to Cognifront Cloud
	cogStoreCloudVariable("~~LM35~~", String(~~temp_val~~, 2));		cogStoreCloudVariable("DHT11", String(temperature, 2));

	delay(2000);		delay(2000);
	}		}

CogWikiEditor: /* Pin Connections */

2026-10-07T05:32:59Z

Pin Connections

← Older revision		Revision as of 05:32, 7 October 2026
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	\|-		\|-
	\| VCC		\| VCC
	\| ~~3.3V~~		\| VIN (5V supply)
	\| Power supply		\| Power supply
	\|-		\|-

CogWikiEditor: /* Real Life Example */

2026-10-07T05:31:04Z

Real Life Example

← Older revision		Revision as of 05:31, 7 October 2026
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	== Real Life Example ==		== Real Life Example ==
	Condition Monitoring in Machines and Data Logging: Sensors collect data such as vibration, temperature, or pressure from mechanical systems, which is logged and analysed ~~in Excel~~ for predictive maintenance and fault diagnosis. Also this data can be fed for training a machine learning model.		Condition Monitoring in Machines and Data Logging: Sensors collect data such as vibration, temperature, or pressure from mechanical systems, which is logged and analysed for predictive maintenance and fault diagnosis. Also this data can be fed for training a machine learning model.

CogWikiEditor: /* Observation */

2026-10-07T05:30:20Z

Observation

← Older revision		Revision as of 05:30, 7 October 2026
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	== Observation ==		== Observation ==
	* The ESP32 successfully reads temperature data from the DHT11 sensor.		* The ESP32 successfully reads temperature data from the DHT11 sensor.
			* Data is properly being logged in CSV file, and file is downloaded successfully.

	== Conclusion ==		== Conclusion ==

CogWikiEditor: /* Observation */

2026-10-07T05:29:24Z

Observation

← Older revision		Revision as of 05:29, 7 October 2026
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	== Observation ==		== Observation ==
	* The ESP32 successfully reads temperature data from the ~~LM35~~ sensor.		* The ESP32 successfully reads temperature data from the DHT11 sensor.

	== Conclusion ==		== Conclusion ==

CogWikiEditor: /* Pin Connections */

2026-10-07T05:28:53Z

Pin Connections

← Older revision		Revision as of 05:28, 7 October 2026
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	== Pin Connections ==		== Pin Connections ==

	The following connections are based on the ESP32 and ~~LM35~~ configuration used in the program.		The following connections are based on the ESP32 and DHT11 configuration used in the program.

	{\| class="wikitable"		{\| class="wikitable"
	\|-		\|-
	! ~~LM35~~ Pin		! DHT11 Pin
	! ESP32 Pin		! ESP32 Pin
	! Description		! Description
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	\|-		\|-
	\| DATA / VOUT		\| DATA / VOUT
	\| ~~GPIO34~~		\| GPIO4
	\| Analog temperature output		\| Analog temperature output
	\|}		\|}
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	⚠️ Disconnect your ESP32 from the computer while making or removing component connections.		⚠️ Disconnect your ESP32 from the computer while making or removing component connections.
	</span>		</span>


	== ESP32 Code ==		== ESP32 Code ==

CogWikiEditor: /* Actions: */

2026-10-07T05:27:37Z

Actions:

← Older revision		Revision as of 05:27, 7 October 2026
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	== Actions: ==		== Actions: ==
	# Write ESP32 code to read temperature data from the ~~LM35~~ sensor and send it to a cloud server using Wi-Fi.		# Write ESP32 code to read temperature data from the DHT11 sensor and send it to a cloud server using Wi-Fi.
	# Display this reading on a web-based dashboard in real-time.		# Display this reading on a web-based dashboard in real-time.
			# Download readings data in CSV format.

	== Setting Up Cloud ==		== Setting Up Cloud ==

CogWikiEditor: /* Theory */

2026-10-07T05:26:53Z

Theory

← Older revision		Revision as of 05:26, 7 October 2026
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	== Theory ==		== Theory ==

	'''Internet of Things (IoT)''' is a technology in which physical devices equipped with sensors, processing units and communication capabilities collect and exchange data over a network. IoT enables sensor data to be transmitted to a remote server or cloud platform for storage, monitoring~~, analysis and visualization~~.		'''Internet of Things (IoT)''' is a technology in which physical devices equipped with sensors, processing units and communication capabilities collect and exchange data over a network. IoT enables sensor data to be transmitted to a remote server or cloud platform for storage and monitoring.

	An IoT-based sensor data transmission system generally consists of:		An IoT-based sensor data transmission system generally consists of:
	* '''Sensor:''' Measures a physical ~~quantity~~ and ~~produces an electrical signal corresponding~~ to the ~~measured value~~. In this experiment, the ~~LM35~~ is used to measure temperature.		* '''Sensor:''' Measures physical parameters and provides the measured data to the IoT device. In this experiment, the DHT11 is used to measure temperature and humidity.
	* '''IoT device / Controller:''' Reads the sensor ~~output~~, processes ~~the data~~ and provides network connectivity. In this experiment, the ESP32 acts as the IoT device.		* '''IoT device / Controller:''' Reads the sensor data, processes it and provides network connectivity. In this experiment, the ESP32 acts as the IoT device.
	* '''Communication network:''' Provides connectivity between the IoT device and the server or cloud platform. The ESP32 uses Wi-Fi for communication.		* '''Communication network:''' Provides connectivity between the IoT device and the server or cloud platform. The ESP32 uses Wi-Fi for communication.
	* '''Cloud server:''' Receives and stores the sensor data transmitted by the ESP32. The cloud platform used in this experiment provides facilities for storing ~~and visualizing~~ the sensor data.		* '''Cloud server:''' Receives and stores the sensor data transmitted by the ESP32. The cloud platform used in this experiment provides facilities for storing the sensor data.
	* '''Data storage ~~and analysis~~:''' The collected data can be exported in CSV format ~~and analyzed or visualized using Microsoft Excel or other data-processing tools~~.		* '''Data storage:''' The collected sensor data can be stored on the server and exported in CSV format for further use.

	'''~~LM35~~''' is ~~an analog~~ temperature sensor that ~~produces an output voltage proportional to the~~ temperature. ~~It has a sensitivity of approximately 10 mV per degree Celsius. The ESP32 reads the~~ analog ~~voltage from~~ the LM35 ~~using~~ its ~~analog input~~ and ~~converts the measured voltage into temperature~~.		'''DHT11''' is a digital temperature and humidity sensor that measures temperature and relative humidity. Unlike an analog temperature sensor such as the LM35, the DHT11 provides digital sensor data through its data pin. The sensor contains temperature and humidity sensing elements along with internal signal-processing circuitry.

	The ESP32 ~~is a microcontroller-based development board~~ with ~~built-in Wi-Fi connectivity~~. ~~After reading~~ the temperature from the ~~LM35,~~ the ESP32 connects to a Wi-Fi network and transmits the sensor data to the cloud server using the configured cloud communication mechanism.		The ESP32 communicates with the DHT11 through its digital data pin. It reads the temperature and humidity values from the sensor and processes the received data. The ESP32 then connects to a Wi-Fi network and transmits the sensor data to the cloud server using the configured cloud communication mechanism.

	The cloud server receives the temperature readings and stores them as data records. In this experiment, the readings are collected at regular intervals and can be exported as a '''CSV (Comma-Separated Values)''' file~~. The CSV file can then~~ be ~~opened~~ in ~~Microsoft Excel for further analysis, tabulation and visualization~~.		The cloud server receives the temperature and humidity readings and stores them as data records. In this experiment, the sensor readings are collected at regular intervals and stored on the server. The stored data can be exported as a '''CSV (Comma-Separated Values)''' file, allowing the collected sensor data to be saved in a standard tabular format.

	The overall data flow of the system is:		The overall data flow of the system is:

	<pre>		<pre>
	~~LM35~~ Temperature Sensor		DHT11 Temperature & Humidity Sensor
	↓		↓
	ESP32		ESP32
	↓		↓
	Wi-Fi		Wi-Fi
	↓		↓
	Cloud Server		Cloud Server
	↓		↓
	Data Storage / CSV		Data Storage / CSV

	</pre>		</pre>

	This type of IoT-based data logging system can be used for applications such as environmental monitoring, ~~machine condition~~ monitoring, ~~temperature logging~~ and other systems where sensor measurements need to be collected remotely and ~~analyzed~~.		This type of IoT-based data logging system can be used for applications such as environmental monitoring, indoor temperature and humidity monitoring, weather monitoring and other systems where sensor measurements need to be collected remotely and stored for later use.

	== Actions: ==		== Actions: ==

CogWikiEditor: /* Components Required */

2026-10-07T05:17:21Z

Components Required

← Older revision		Revision as of 05:17, 7 October 2026
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	\|-		\|-
	\| 2		\| 2
	\| ~~LM35~~ temperature sensor		\| DHT11 temperature sensor
	\| 1		\| 1
	\|-		\|-

CogWikiEditor: /* Objectives */

2026-10-07T05:17:00Z

Objectives

← Older revision		Revision as of 05:17, 7 October 2026
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	== Objectives ==		== Objectives ==
	* To understand the concept of IoT-based sensor data communication.		* To understand the concept of IoT-based sensor data communication.
	* To interface an ~~LM35~~ temperature sensor with an ESP32 development board.		* To interface an DHT11 temperature sensor with an ESP32 development board.
	* To read temperature data from the ~~LM35~~ sensor using the ESP32.		* To read temperature data from the DHT11 sensor using the ESP32.
	* To connect the ESP32 to a Wi-Fi network and transmit sensor data to a cloud server.		* To connect the ESP32 to a Wi-Fi network and transmit sensor data to a cloud server.
	* To store and log the transmitted sensor data in CSV format.		* To store and log the transmitted sensor data in CSV format.