Thursday, 10 September 2026

SmartGuard-3P: IoT-Based Real-Time Health Monitoring and Protection of Three-Phase Transformers Using ESP32 and ThingSpeak.

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1.IoT-Based Three-Phase Transformer Health Monitoring and Protection Using ESP32 and ThingSpeak.
2.SmartGuard-3P: IoT-Based Real-Time Health Monitoring and Protection of Three-Phase Transformers Using ESP32.
3.Three-Phase Transformer Health Monitoring Using ESP32 and ThingSpeak | IoT-Based Condition Monitoring System.
4.IoT-Based Real-Time Monitoring and Fault Detection of Three-Phase Distribution Transformers Using ESP32.
5.Design and Implementation of an IoT-Based Three-Phase Transformer Health Monitoring and Protection System.
6.Smart Three-Phase Transformer Monitoring and Protection System Using ESP32 and ThingSpeak.
7.IoT-Enabled Real-Time Condition Monitoring of Three-Phase Distribution Transformers Using ESP32.
8.ESP32-Based IoT System for Real-Time Three-Phase Transformer Health Monitoring and Fault Detection.
9.IoT-Based Three-Phase Transformer Condition Monitoring and Early Fault Detection Using ESP32.
10.Real-Time Three-Phase Transformer Health Monitoring and Protection Using ESP32 and IoT.
11.Design and Implementation of an IoT-Enabled Real-Time Condition Monitoring and Protection System for Three-Phase Distribution Transformers.
12.An ESP32-Based IoT Framework for Real-Time Condition Monitoring and Fault Detection in Three-Phase Distribution Transformers.
13.IoT-Enabled Real-Time Condition Monitoring and Protection of Three-Phase Transformers Using ESP32 and ThingSpeak.
14.Design and Development of an ESP32-Based IoT System for Three-Phase Transformer Health Assessment and Fault Detection.
15.Real-Time IoT-Based Monitoring of Electrical and Thermal Parameters for Three-Phase Transformer Condition Assessment.
16.An IoT-Based Framework for Real-Time Voltage, Current, Temperature and Oil-Level Monitoring of Three-Phase Transformers.
17.Development of an ESP32-Enabled Smart Monitoring System for Real-Time Three-Phase Transformer Health Assessment.
18.IoT-Based Condition Monitoring and Early Fault Detection of Three-Phase Distribution Transformers Using ESP32.
19.A Smart IoT Architecture for Real-Time Monitoring and Protection of Three-Phase Distribution Transformers.
20.Real-Time Transformer Health Monitoring and Fault Protection Using ESP32-Based IoT Technology.
21.TransfoSense: An IoT-Enabled Intelligent Three-Phase Transformer Health Monitoring and Fault Detection System.
22.Transformer360: Smart IoT-Based Real-Time Monitoring and Protection of Three-Phase Distribution Transformers.
23.GridGuard-3P: An IoT-Enabled Smart Transformer Monitoring, Fault Detection and Protection System Using ESP32.
24.TransfoShield: Intelligent IoT-Based Condition Monitoring and Protection of Three-Phase Distribution Transformers.
25.SmartTrans-3P: An ESP32 and IoT-Based Intelligent Three-Phase Transformer Health Monitoring System.
26.TransfoWatch: IoT-Based Real-Time Monitoring of Voltage, Current, Temperature and Oil Level in Three-Phase Transformers.
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30.TrafoSentinel: Continuous IoT-Based Health Monitoring and Early Fault Detection for Three-Phase Transformers.
31.IoT-Based Three-Phase Transformer Monitoring of Voltage, Current, Temperature and Oil Level Using ESP32.
32.Real-Time Transformer Health Assessment Using Multi-Parameter IoT Sensing and ESP32.
33.ESP32-Based Transformer Condition Monitoring System for Voltage, Current, Temperature and Oil-Level Detection.
34.IoT-Based Multi-Parameter Health Monitoring and Fault Detection of Three-Phase Transformers.
35.Real-Time Monitoring of Electrical and Thermal Parameters in Three-Phase Transformers Using ESP32 and ThingSpeak.
36.Smart IoT-Based Transformer Condition Monitoring Using Voltage, Current, Temperature and Oil-Level Sensors.
37.Three-Phase Distribution Transformer Health Assessment Through Real-Time IoT-Based Multi-Parameter Monitoring.
38.IoT-Enabled Multi-Parameter Transformer Monitoring and Early Warning System Using ESP32.
39.ESP32-Based Real-Time Three-Phase Transformer Health and Safety Monitoring System.
40.Real-Time IoT-Based Three-Phase Transformer Condition Assessment and Fault Warning System.
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46.Intelligent IoT Architecture for Continuous Condition Monitoring, Anomaly Detection and Predictive Protection of Three-Phase Transformers.
47.IoT-Based Predictive Health Assessment and Early Fault Detection of Three-Phase Distribution Transformers Using ESP32.
48.Smart Transformer Health Intelligence Using ESP32-Based Edge Monitoring and Cloud Analytics.
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50.Advanced IoT-Based Three-Phase Transformer Health Monitoring, Fault Detection and Predictive Condition Assessment.
51.IoT-Based Three-Phase Transformer Health Monitoring and Protection Using ESP32 and ThingSpeak.
52.SmartGuard-3P: IoT-Based Real-Time Health Monitoring and Protection of Three-Phase Transformers Using ESP32.
53.IoT-Based Real-Time Monitoring and Fault Detection of Three-Phase Distribution Transformers Using ESP32.
54.Design and Implementation of an IoT-Based Three-Phase Transformer Health Monitoring and Protection System.
55.TransfoSense: An IoT-Enabled Intelligent Three-Phase Transformer Health Monitoring and Fault Detection System.
56.Three-Phase Transformer Health Monitoring Using ESP32 and ThingSpeak \| IoT-Based Condition Monitoring System.
57.Transformer360: Smart IoT-Based Real-Time Monitoring and Protection of Three-Phase Distribution Transformers.
58.An ESP32-Based IoT Framework for Real-Time Condition Monitoring and Fault Detection in Three-Phase Distribution Transformers.
59.IoT-Based Three-Phase Transformer Condition Monitoring and Early Fault Detection Using ESP32.
60.Real-Time Monitoring of Electrical and Thermal Parameters in Three-Phase Transformers Using ESP32 and ThingSpeak.

Wednesday, 9 September 2026

AttendX: Smart RFID-Based Student Attendance System Using ESP32 & IoT with Real-Time Parent Alerts with Cloud Integration

1.AttendX: An Intelligent Edge-to-Cloud RFID–IoT Platform for Automated Student Attendance, Real-Time Parent Alerts, and Cloud Analytics.
2.Smart RFID Attendance System Using ESP32 and IoT with Real-Time Parent Notifications and Cloud Analytics.
3.Design and Development of an ESP32-Based RFID Student Attendance System with Cloud Integration and Real-Time Parent Notifications.
4.AttendSphere: A Secure Edge-to-Cloud Framework for Intelligent Student Attendance and Presence Management.
5.An IoT-Enabled RFID Framework for Automated Student Attendance Monitoring and Real-Time Parent Alert Generation.
6.ESP32-Based Smart RFID Attendance System with IoT Connectivity, Cloud Monitoring, and Real-Time Alerts.
7.AttendSync: A Smart RFID–IoT Framework for Real-Time Student Attendance and Parent Engagement.
8.EduPulse: An Intelligent IoT Platform for Real-Time Student Attendance, Monitoring, and Notifications.
9.Design and Implementation of a Smart RFID–IoT Architecture for Real-Time Student Attendance and Cloud-Based Monitoring.
10.PresenceGuard: An Intelligent RFID and Edge-IoT Framework for Secure Student Attendance and Real-Time Notifications.
11.Smart Student Attendance System Using ESP32, RFID, IoT, Cloud Computing, and Real-Time Alerts.
12.AttendIQ: Intelligent RFID-Based Attendance Automation with Cloud Integration and Attendance Analytics.
13.EduTrack: An Intelligent RFID and IoT-Based Student Attendance Monitoring and Alert System.
14.Real-Time Student Attendance Monitoring Using ESP32, RFID, IoT Connectivity, and Cloud-Based Alert Mechanisms.
15.ClassGuard: An IoT-Enabled RFID System for Automated Attendance and Real-Time Parent Alerts.
16.A Cloud-Integrated IoT Framework for Automated RFID-Based Student Attendance and Real-Time Stakeholder Notifications.
17.AttendLink: A Cloud-Integrated RFID–IoT Ecosystem for Student Attendance and Parent Communication.
18.ESP32 RFID Attendance System with Cloud Database, Real-Time Notifications, and Student Attendance Analytics.
19.EduSentinel: A Smart RFID–IoT Architecture for Continuous Student Presence Monitoring and Automated Alerts.
20.SmartPresence: A Real-Time IoT Framework for Automated Student Attendance and Parent Notification.
21.AttendGuard: A Secure Smart Attendance Ecosystem with RFID Authentication, Edge Processing, and Real-Time Alerts.
22.IoT-Based RFID Student Attendance System Using ESP32 with Real-Time Parent Alerts and Cloud Dashboard.
23.EduWatch: An Intelligent IoT-Based Student Presence, Attendance, and Alert Management System.
24.CampusSense: An ESP32–RFID Smart Attendance and Student Presence Monitoring Platform.
25.AttendCloud: A Smart RFID–ESP32 Framework for Automated Attendance and Real-Time Stakeholder Notifications.
26.Intelligent Student Attendance Monitoring Using RFID and ESP32 with IoT-Based Cloud Integration.
27.Automated Student Attendance System Using RFID and ESP32 with Real-Time IoT Notifications.
28.ClassPulse: Real-Time RFID Attendance Monitoring with ESP32, Cloud Connectivity, and Parent Alerts.
29.EduTrace: A Cloud-Connected Student Presence Intelligence Platform Using RFID and Edge IoT.
30.SmartCampus360: An IoT-Based Student Attendance and Real-Time Monitoring Platform Using RFID and ESP32.
31.An ESP32-Enabled Intelligent Attendance Monitoring System Using RFID, Cloud Computing, and Real-Time Notification Services.
32.IoT-Enabled Smart Attendance Management Using RFID and ESP32 with Cloud-Based Analytics and Alerts.
33.PresenceNet: An Intelligent RFID–IoT Network for Automated Attendance and Stakeholder Communication.
34.Intelligent RFID-Based Student Attendance and Presence Monitoring System with ESP32 and Cloud Services.
35.AttendAIoT: An Intelligent Edge-to-Cloud Architecture for Automated Student Attendance and Behavioral Insights.
36.SchoolSync: An Intelligent RFID Attendance System with ESP32, Cloud Monitoring, and Parent Alerts.
37.SmartClass360: A Connected RFID–IoT Platform for Student Attendance and Presence Management.
38.Real-Time RFID-Based Student Attendance and Parent Notification System Using ESP32 and IoT.
39.Secure Cloud-Connected RFID Attendance Architecture for Automated Student Identification and Attendance Management.
40.IoT-Based Smart School Attendance System Using ESP32 and RFID with Automated Parent Notifications.
41.Automated RFID Student Attendance Monitoring with ESP32, Cloud Synchronization, and Real-Time Alerts.
42.Cloud-Integrated Smart Attendance System Using ESP32 and RFID for Real-Time Student Monitoring.
43.EduConnect: Smart RFID Attendance with ESP32, IoT Cloud Integration, and Real-Time Parent Communication.
44.ClassSentinel: An IoT-Driven Student Attendance, Presence Verification, and Parent Alert Ecosystem.
45.MyAttend: A Smart RFID and ESP32-Based Student Attendance and Real-Time Notification System.
46.Next-Generation Student Attendance Monitoring Using RFID, ESP32, IoT, and Cloud Analytics.
47.Smart Attendance and Student Presence Intelligence Using ESP32, RFID, IoT, and Real-Time Notifications.
48.An Intelligent Cloud-Based RFID Attendance Management System with ESP32 and Automated Stakeholder Alerts.
49.Connected Student Attendance Management Using RFID and ESP32 with IoT-Based Monitoring and Analytics.
50.Automated Student Attendance and Presence Monitoring Using ESP32, RFID, Cloud Computing, and Real-Time Alerts.
51.AttendX: An Intelligent Edge-to-Cloud RFID–IoT Platform for Automated Student Attendance, Real-Time Parent Alerts, and Cloud Analytics.
52.Design and Development of an ESP32-Based RFID Student Attendance System with Cloud Integration and Real-Time Parent Notifications.
53.Smart RFID Attendance System Using ESP32 and IoT with Real-Time Parent Notifications and Cloud Analytics.
54.An IoT-Enabled RFID Framework for Automated Student Attendance Monitoring and Real-Time Parent Alert Generation.
55.AttendSphere: A Secure Edge-to-Cloud Framework for Intelligent Student Attendance and Presence Management.
56.AttendIQ: Intelligent RFID-Based Attendance Automation with Cloud Integration and Attendance Analytics.
57.EduPulse: An Intelligent IoT Platform for Real-Time Student Attendance, Monitoring, and Notifications.
58.AttendSync: A Smart RFID–IoT Framework for Real-Time Student Attendance and Parent Engagement.
59.AttendGuard: A Secure Smart Attendance Ecosystem with RFID Authentication, Edge Processing, and Real-Time Alerts.
60.ESP32-Based Smart RFID Attendance System with IoT Connectivity, Cloud Monitoring, and Real-Time Alerts.

Sunday, 6 September 2026

IoT-Based Three-Phase Transformer Monitoring and Protection System Using ESP32 and ThingSpeak

Yes. This can be developed as a complete academic/industrial-style IoT project combining:

  • ESP32 as the edge controller
  • Three-phase transformer sensing
  • Local protection/interlocking
  • ThingSpeak cloud dashboard
  • n8n automation
  • AI-based fault interpretation
  • Telegram text + voice alerts
  • Google Sheets event/history logging
  • A custom IoT web dashboard
  • Optional AI-agent commands and remote control

The most important design principle is: the ESP32 must perform the immediate protection locally; cloud/AI/n8n must never be the only protection layer. Internet or AI failure must not prevent the transformer from being protected.

The ESP32 Arduino platform officially supports Wi-Fi and ADC/peripheral functionality suitable for this type of edge-monitoring application.  ThingSpeak provides REST APIs for writing and reading channel data.  n8n provides Webhook and Telegram nodes for event-driven automation. 

1. Proposed Project Title

IoT-Based Three-Phase Transformer Monitoring, Protection and AI-Agentic Alert System Using ESP32, ThingSpeak and n8n Automation

Alternative title

AI-Powered Agentic IoT Three-Phase Transformer Monitoring and Protection System Using ESP32, n8n, ThingSpeak, Telegram and Google Sheets


2. Complete Project Concept

The proposed system continuously monitors a three-phase transformer and measures parameters such as:

  • Phase-R voltage
  • Phase-Y voltage
  • Phase-B voltage
  • Phase-R current
  • Phase-Y current
  • Phase-B current
  • Transformer/load temperature
  • Frequency
  • Phase imbalance
  • Overvoltage
  • Undervoltage
  • Overcurrent
  • Overtemperature
  • Power/load condition
  • Protection status
  • Internet/device status

The ESP32 collects the sensor information and performs local fault detection.

Normal data is uploaded to ThingSpeak.

When a fault occurs:

Transformer
     ↓
Sensors
     ↓
ESP32
     ↓
Local Protection Decision
     ↓
Fault detected?
   /       \
 NO         YES
 |           |
Cloud       Trip/Alarm
 |           |
ThingSpeak   ↓
 |         n8n Webhook
 |           ↓
 |       AI Analysis
 |           ↓
 |     Telegram Alert
 |           ↓
 |       Voice Alert
 |           ↓
 |     Google Sheets
 ↓
Dashboard

3. High-Level Architecture

                 ┌──────────────────────────┐
                 │     3-PHASE TRANSFORMER  │
                 │                          │
                 │       R       Y       B  │
                 └───────┬───────┬───────┬──┘
                         │       │       │
             ┌───────────┴───────┴───────┴───────────┐
             │               SENSORS                  │
             │                                         │
             │ Voltage     Current     Temperature     │
             │ Sensors     Sensors      Sensor         │
             └───────────────┬─────────────────────────┘
                             │
                             ↓
                  ┌─────────────────────┐
                  │       ESP32         │
                  │                     │
                  │ ADC / GPIO / Wi-Fi  │
                  │                     │
                  │ Monitoring          │
                  │ Protection Logic    │
                  │ Fault Detection     │
                  └──────┬──────────────┘
                         │
              ┌──────────┴───────────┐
              │                      │
              ↓                      ↓
       LOCAL PROTECTION          Wi-Fi/Internet
              │                      │
              ↓                      ↓
      Relay/Contactor          ThingSpeak
      / Trip Circuit                │
              │                     ↓
              ↓                Cloud Dashboard
        Transformer                │
          isolated                │
                                n8n
                                 │
              ┌──────────────────┼────────────────┐
              ↓                  ↓                ↓
          AI Agent           Telegram        Google Sheets
              │                  │                │
              ↓                  ↓                ↓
        Fault Analysis      Text Alert       Event Log
                                 │
                                 ↓
                            Voice Alert

4. Safety Architecture

This is particularly important because transformer monitoring involves potentially lethal voltages.

Do not connect transformer primary or secondary mains directly to ESP32 GPIO/ADC pins.

Use properly rated:

  • Isolation transformers / voltage transformers
  • Current transformers
  • Hall-effect current sensors
  • Opto-isolation where appropriate
  • Fuses
  • MCB
  • Surge protection
  • Proper earthing
  • Isolation barriers
  • Rated contactors
  • Proper enclosure

The ESP32 side should operate at its low-voltage logic level, while measurement/protection interfaces provide the necessary electrical isolation.

For an academic prototype, it is much safer to demonstrate using a low-voltage isolated three-phase source or laboratory transformer model.


5. Hardware Components

Main controller

ESP32 Development Board

Recommended:

  • ESP32 DevKit
  • ESP32-WROOM-based board
  • USB programming interface
  • Wi-Fi connectivity

Espressif's Arduino documentation currently documents the ESP32 Arduino core and supported ESP32 families. 

Sensors

A practical prototype can use:

Parameter Sensor/interface
Voltage R Isolated voltage sensor
Voltage Y Isolated voltage sensor
Voltage B Isolated voltage sensor
Current R CT/Hall current sensor
Current Y CT/Hall current sensor
Current B CT/Hall current sensor
Temperature DS18B20 / PT100 interface
Frequency Zero-crossing isolated circuit
Trip feedback Digital input
Contactor status Digital input

6. Recommended Pin Allocation

One possible ESP32 mapping:

ESP32
────────────────────────────

GPIO 34  ← Voltage R
GPIO 35  ← Voltage Y
GPIO 32  ← Voltage B

GPIO 33  ← Current R
GPIO 36  ← Current Y
GPIO 39  ← Current B

GPIO 4   ← Temperature sensor

GPIO 25  ← Trip relay
GPIO 26  ← Alarm relay
GPIO 27  ← Reset input

GPIO 14  ← Contactor feedback
GPIO 13  ← Emergency-stop feedback

GPIO 2   → Status LED

Important: exact ADC suitability and pin availability depend on the specific ESP32 board. Verify the board's pinout before building.


7. Measurement Chain

The measurement architecture should look like:

HIGH-VOLTAGE SIDE
       │
       │
       ↓
┌───────────────────┐
│ Isolation Sensor  │
└─────────┬─────────┘
          │
          ↓
 Signal conditioning
          │
          ↓
┌───────────────────┐
│ ESP32 ADC         │
└─────────┬─────────┘
          │
          ↓
 Digital processing
          │
          ↓
 RMS calculation
          │
          ↓
 Fault analysis

For current:

Transformer conductor
        │
        ↓
       CT
        │
        ↓
Burden / signal conditioning
        │
        ↓
ESP32 ADC

8. Three-Phase Monitoring

The ESP32 calculates:

Phase voltage

VR, VY, VB

Phase current

IR, IY, IB

Average voltage

Vavg=VR+VY+VB3

Average current

Iavg=IR+IY+IB3

Voltage imbalance

Vimbalance=max⁡(VR,VY,VB)−min⁡(VR,VY,VB)Vavg×100

Current imbalance

Iimbalance=max⁡(IR,IY,IB)−min⁡(IR,IY,IB)Iavg×100

These values can be used for warning and protection decisions.


9. Protection Logic

Example engineering thresholds:

Condition Example threshold
Undervoltage < 90% nominal
Overvoltage > 110% nominal
Overcurrent warning > 90% rated
Overcurrent trip > 110% rated
Temperature warning 70°C
Temperature trip 85°C
Voltage imbalance warning > 3%
Voltage imbalance trip > 5%

These are example values only. Actual thresholds must come from the transformer rating, protection study, applicable standards, sensor characteristics and engineering requirements.


10. Two-Level Protection

This project should deliberately use two separate layers.

Layer 1 — Local protection

ESP32 immediately evaluates:

Voltage
Current
Temperature
Phase imbalance
       ↓
Protection algorithm
       ↓
Fault?
       ↓
Relay/Trip

This should continue operating even if:

  • Wi-Fi fails
  • ThingSpeak fails
  • n8n fails
  • Telegram fails
  • AI service fails
  • Internet fails

Layer 2 — Cloud intelligence

Cloud services provide:

  • Historical analysis
  • Notifications
  • Reports
  • AI interpretation
  • Maintenance suggestions
  • Event logging
  • Remote dashboard

11. Fault State Machine

             ┌──────────────┐
             │    NORMAL    │
             └──────┬───────┘
                    │
              abnormal value
                    ↓
             ┌──────────────┐
             │    WARNING   │
             └──────┬───────┘
                    │
              condition persists
                    ↓
             ┌──────────────┐
             │    TRIP      │
             └──────┬───────┘
                    │
             Contactor OFF
                    │
                    ↓
             ┌──────────────┐
             │   LOCKOUT    │
             └──────┬───────┘
                    │
             Manual reset
                    ↓
             ┌──────────────┐
             │    NORMAL    │
             └──────────────┘

This is better than simply saying:

if fault -> relay off

because it prevents rapid relay oscillation.


12. ThingSpeak Architecture

ThingSpeak can store the measurements and display them as charts. Its REST API supports channel writes using HTTP GET or POST. 

A suggested channel structure:

Field Parameter
Field 1 Voltage R
Field 2 Voltage Y
Field 3 Voltage B
Field 4 Current R
Field 5 Current Y
Field 6 Current B
Field 7 Temperature
Field 8 Fault code

Additional calculated values can be sent through another channel if necessary.

For example:

ThingSpeak Channel
│
├── Field 1 = V_R
├── Field 2 = V_Y
├── Field 3 = V_B
├── Field 4 = I_R
├── Field 5 = I_Y
├── Field 6 = I_B
├── Field 7 = Temperature
└── Field 8 = Fault Code

ThingSpeak uses channel Write API Keys for writing data. 


13. ESP32 → ThingSpeak

The ESP32 sends an HTTP request such as:

https://api.thingspeak.com/update.json

with parameters conceptually like:

api_key=YOUR_WRITE_KEY
field1=230
field2=231
field3=229
field4=4.2
field5=4.1
field6=4.3
field7=52
field8=0

ThingSpeak documents this update endpoint and its field parameters. 


14. IoT Webpage

I recommend building a separate dashboard rather than relying only on ThingSpeak.

Example:

┌────────────────────────────────────────────────────────┐
│       THREE-PHASE TRANSFORMER IoT DASHBOARD            │
├────────────────────────────────────────────────────────┤
│                                                        │
│  STATUS: 🟢 NORMAL        ESP32: ONLINE               │
│                                                        │
├──────────┬──────────┬──────────┬───────────────────────┤
│ V-R      │ V-Y      │ V-B      │ Temperature           │
│ 230 V    │ 231 V    │ 229 V    │ 54 °C                 │
├──────────┼──────────┼──────────┼───────────────────────┤
│ I-R      │ I-Y      │ I-B      │ Frequency             │
│ 4.2 A    │ 4.1 A    │ 4.3 A    │ 50 Hz                 │
└──────────┴──────────┴──────────┴───────────────────────┘

             LIVE GRAPHS

 Voltage
 240 ┤       ╭───╮
 230 ┤───────╯   ╰────────
 220 ┤
     └────────────────────── time

 Current
  6  ┤
  4  ┤──────╭────╮─────────
  2  ┤──────╯    ╰─────────
     └────────────────────── time

             FAULT HISTORY

Time       Fault              Action
20:10      Normal             —
20:15      Temp Warning       Alert
20:20      Normal             —

15. n8n Automation Architecture

n8n becomes the automation/orchestration layer.

             ESP32
               │
               │ HTTP POST
               ↓
        ┌──────────────┐
        │ n8n Webhook  │
        └──────┬───────┘
               │
               ↓
        Validate JSON
               │
               ↓
        ┌──────────────┐
        │ IF / Switch  │
        └──────┬───────┘
               │
        ┌──────┴────────────┐
        │                   │
       NORMAL              FAULT
        │                   │
        ↓                   ↓
   Google Sheets       AI Analysis
                            │
                            ↓
                      Fault diagnosis
                            │
                  ┌─────────┴──────────┐
                  ↓                    ↓
              Telegram             Sheets
                  │
                  ↓
            Voice message

n8n's Webhook node is specifically intended to receive data from applications/services and act as a workflow trigger. 


16. ESP32 → n8n JSON

Instead of sending a complicated query string, use JSON.

Example:

{
  "device": "TX-001",
  "voltage_r": 230.4,
  "voltage_y": 229.8,
  "voltage_b": 231.2,
  "current_r": 4.8,
  "current_y": 4.7,
  "current_b": 4.9,
  "temperature": 57.3,
  "frequency": 50.01,
  "voltage_imbalance": 0.61,
  "current_imbalance": 4.08,
  "fault_code": 0,
  "status": "NORMAL"
}

When there is a fault:

{
  "device": "TX-001",
  "voltage_r": 230.4,
  "voltage_y": 229.8,
  "voltage_b": 231.2,
  "current_r": 12.8,
  "current_y": 12.5,
  "current_b": 13.1,
  "temperature": 88.2,
  "fault_code": 3,
  "status": "TRIP"
}

17. AI Agent Architecture

The AI agent should not directly control the transformer without deterministic safety controls.

Instead:

Sensor data
     ↓
ESP32 protection
     ↓
n8n
     ↓
AI Agent
     ↓
Interpretation
     ↓
Recommended action
     ↓
Safety policy
     ↓
Notification / approved action

The AI can answer questions such as:

"Why did the transformer trip?"

The AI receives:

Voltage R = 231 V
Voltage Y = 230 V
Voltage B = 229 V

Current R = 13.2 A
Current Y = 13.0 A
Current B = 13.5 A

Temperature = 91°C

Fault = Overtemperature

and generates:

TRANSFORMER FAULT ANALYSIS

Device: TX-001

Severity: HIGH

Primary condition:
Transformer temperature exceeded the configured
trip threshold.

Measured temperature: 91°C

Recommended checks:
1. Verify cooling system.
2. Check transformer loading.
3. Inspect ventilation.
4. Check recent current trend.
5. Do not re-energize until temperature and cause
   are verified safe.

18. Agentic IoT Concept

The "agentic" part can be structured as:

                    ┌──────────────┐
                    │   Operator   │
                    └──────┬───────┘
                           │
                    Telegram message
                           │
                           ↓
                    ┌──────────────┐
                    │  AI Agent    │
                    └──────┬───────┘
                           │
            ┌──────────────┼──────────────┐
            ↓              ↓              ↓
       Read Status      Analyze Fault   Get History
            │              │              │
            └──────────────┼──────────────┘
                           ↓
                     Safety Policy
                           │
                           ↓
                    Allowed Action?
                     /          \
                   NO            YES
                   │              │
                   ↓              ↓
              Explain       Execute approved
              rejection        operation

For example:

Operator:
"What's the transformer status?"

AI Agent:
"TX-001 is operating normally.
R/Y/B voltages are within limits.
Temperature is 53°C.
Load current is approximately 4.2 A."

Operator:
"Why did it trip yesterday?"

AI Agent:
"At 14:32 the temperature reached 87°C.
The trip was preceded by increasing phase current.
The likely cause is excessive loading or inadequate cooling."

Operator:
"Reset the transformer."

AI Agent:
"Reset command is not permitted until the local
interlock confirms the transformer is safe."

That final safety behavior is important.


19. Telegram Alert Workflow

Telegram's Bot API provides a sendVoice method for playable voice messages. 

The workflow can be:

Fault
  ↓
n8n
  ↓
AI Agent
  ↓
Generate alert text
  ↓
Text-to-Speech
  ↓
Audio file
  ↓
Telegram
  ↓
Operator phone

Example alert:

🚨 TRANSFORMER ALERT

Device: TX-001

Fault: Overtemperature

Temperature: 88.4 °C

Status: TRIPPED

Phase currents:
R = 12.7 A
Y = 12.5 A
B = 12.9 A

Immediate inspection required.

Then a voice notification:

"Attention. Transformer TX-001 has tripped due to high temperature. The measured temperature is 88.4 degrees Celsius. Please inspect the transformer before re-energizing."


20. Google Sheets Logging

Every event can be recorded:

Timestamp Device VR VY VB IR IY IB Temp Fault Action
20:10 TX001 230 231 229 4.2 4.1 4.3 52 NORMAL
20:25 TX001 229 231 230 8.1 8.4 8.0 71 TEMP-WARN ALERT
20:31 TX001 228 229 230 12.5 12.6 12.8 87 TEMP-TRIP TRIP

This creates a useful maintenance history.


21. Complete n8n Workflow

A practical workflow can be:

[Webhook]
    │
    ↓
[JSON Validation]
    │
    ↓
[Set / Normalize Data]
    │
    ↓
[Google Sheets - Log]
    │
    ↓
[Switch Fault Status]
    │
 ┌──┴───────────────┐
 │                  │
NORMAL             FAULT
 │                  │
 ↓                  ↓
End          [AI Agent]
                   │
                   ↓
             [Generate Alert]
                   │
          ┌────────┴─────────┐
          ↓                  ↓
     [Telegram Text]    [Text-to-Speech]
                              │
                              ↓
                       [Telegram Voice]
                              │
                              ↓
                       [Google Sheets]

n8n's Telegram integration supports Telegram automation and message operations. 


22. ESP32 Software Structure

The firmware should be divided into modules:

ESP32 Firmware
│
├── sensors.cpp
│   ├── readVoltage()
│   ├── readCurrent()
│   └── readTemperature()
│
├── protection.cpp
│   ├── checkOverVoltage()
│   ├── checkUnderVoltage()
│   ├── checkOverCurrent()
│   ├── checkTemperature()
│   └── checkImbalance()
│
├── cloud.cpp
│   ├── sendThingSpeak()
│   └── sendN8N()
│
├── webserver.cpp
│   └── local dashboard
│
└── main.cpp

23. ESP32 Complete Prototype Code

Below is a prototype firmware architecture. The sensor conversion constants must be calibrated for the actual voltage/current interfaces.

#include <WiFi.h>
#include <HTTPClient.h>
#include <ArduinoJson.h>
#include <OneWire.h>
#include <DallasTemperature.h>

// =====================================================
// Wi-Fi
// =====================================================

const char* WIFI_SSID = "YOUR_WIFI";
const char* WIFI_PASSWORD = "YOUR_PASSWORD";

// =====================================================
// ThingSpeak
// =====================================================

const char* THINGSPEAK_URL =
    "https://api.thingspeak.com/update";

const char* THINGSPEAK_API_KEY =
    "YOUR_THINGSPEAK_WRITE_KEY";

// =====================================================
// n8n
// =====================================================

const char* N8N_WEBHOOK =
    "https://YOUR-N8N-DOMAIN/webhook/transformer";

// =====================================================
// Pins
// =====================================================

#define VOLTAGE_R_PIN 34
#define VOLTAGE_Y_PIN 35
#define VOLTAGE_B_PIN 32

#define CURRENT_R_PIN 33
#define CURRENT_Y_PIN 36
#define CURRENT_B_PIN 39

#define TEMP_PIN 4

#define TRIP_RELAY_PIN 25
#define ALARM_RELAY_PIN 26

#define CONTACTOR_FB_PIN 14
#define RESET_PIN 27

// =====================================================
// Temperature
// =====================================================

OneWire oneWire(TEMP_PIN);
DallasTemperature temperatureSensor(&oneWire);

// =====================================================
// Protection thresholds
// =====================================================

float NOMINAL_VOLTAGE = 230.0;

float OVERVOLTAGE_LIMIT =
    NOMINAL_VOLTAGE * 1.10;

float UNDERVOLTAGE_LIMIT =
    NOMINAL_VOLTAGE * 0.90;

float MAX_CURRENT = 10.0;

float TEMPERATURE_WARNING = 70.0;
float TEMPERATURE_TRIP = 85.0;

float VOLTAGE_IMBALANCE_LIMIT = 5.0;
float CURRENT_IMBALANCE_LIMIT = 10.0;

// =====================================================
// Timing
// =====================================================

unsigned long lastCloudUpdate = 0;

const unsigned long CLOUD_INTERVAL =
    15000;

// =====================================================
// Structure
// =====================================================

struct TransformerData {

  float voltageR;
  float voltageY;
  float voltageB;

  float currentR;
  float currentY;
  float currentB;

  float temperature;

  float voltageImbalance;
  float currentImbalance;

  int faultCode;

  bool tripped;

};

TransformerData data;

// =====================================================
// Read analog sensor
// =====================================================

float readAnalogAverage(int pin, int samples = 100) {

  long total = 0;

  for (int i = 0; i < samples; i++) {

    total += analogRead(pin);

    delayMicroseconds(100);
  }

  return (float)total / samples;
}

// =====================================================
// Convert voltage sensor reading
// =====================================================

float readVoltage(int pin) {

  float adc = readAnalogAverage(pin);

  // --------------------------------------------------
  // Replace this with calibration equation
  // --------------------------------------------------

  float voltage = adc * 0.100;

  return voltage;
}

// =====================================================
// Convert current sensor reading
// =====================================================

float readCurrent(int pin) {

  float adc = readAnalogAverage(pin);

  // --------------------------------------------------
  // Replace with calibrated CT/Hall conversion
  // --------------------------------------------------

  float current = adc * 0.010;

  return current;
}

// =====================================================
// Read temperature
// =====================================================

float readTemperature() {

  temperatureSensor.requestTemperatures();

  return temperatureSensor.getTempCByIndex(0);
}

// =====================================================
// Calculate imbalance
// =====================================================

float calculateImbalance(
    float a,
    float b,
    float c) {

  float average =
      (a + b + c) / 3.0;

  if (average <= 0.01)
    return 0;

  float maxValue =
      max(a, max(b, c));

  float minValue =
      min(a, min(b, c));

  return ((maxValue - minValue)
          / average) * 100.0;
}

// =====================================================
// Read all sensors
// =====================================================

void readSensors() {

  data.voltageR =
      readVoltage(VOLTAGE_R_PIN);

  data.voltageY =
      readVoltage(VOLTAGE_Y_PIN);

  data.voltageB =
      readVoltage(VOLTAGE_B_PIN);

  data.currentR =
      readCurrent(CURRENT_R_PIN);

  data.currentY =
      readCurrent(CURRENT_Y_PIN);

  data.currentB =
      readCurrent(CURRENT_B_PIN);

  data.temperature =
      readTemperature();

  data.voltageImbalance =
      calculateImbalance(
          data.voltageR,
          data.voltageY,
          data.voltageB);

  data.currentImbalance =
      calculateImbalance(
          data.currentR,
          data.currentY,
          data.currentB);
}

// =====================================================
// Protection
// =====================================================

void protectionCheck() {

  data.faultCode = 0;

  // -----------------------------------------------
  // Overvoltage
  // -----------------------------------------------

  if (
      data.voltageR > OVERVOLTAGE_LIMIT ||
      data.voltageY > OVERVOLTAGE_LIMIT ||
      data.voltageB > OVERVOLTAGE_LIMIT
  ) {

    data.faultCode = 1;
  }

  // -----------------------------------------------
  // Undervoltage
  // -----------------------------------------------

  if (
      data.voltageR < UNDERVOLTAGE_LIMIT ||
      data.voltageY < UNDERVOLTAGE_LIMIT ||
      data.voltageB < UNDERVOLTAGE_LIMIT
  ) {

    data.faultCode = 2;
  }

  // -----------------------------------------------
  // Overcurrent
  // -----------------------------------------------

  if (
      data.currentR > MAX_CURRENT ||
      data.currentY > MAX_CURRENT ||
      data.currentB > MAX_CURRENT
  ) {

    data.faultCode = 3;
  }

  // -----------------------------------------------
  // Overtemperature
  // -----------------------------------------------

  if (
      data.temperature >= TEMPERATURE_TRIP
  ) {

    data.faultCode = 4;
  }

  // -----------------------------------------------
  // Voltage imbalance
  // -----------------------------------------------

  if (
      data.voltageImbalance >
      VOLTAGE_IMBALANCE_LIMIT
  ) {

    data.faultCode = 5;
  }

  // -----------------------------------------------
  // Current imbalance
  // -----------------------------------------------

  if (
      data.currentImbalance >
      CURRENT_IMBALANCE_LIMIT
  ) {

    data.faultCode = 6;
  }

  // -----------------------------------------------
  // Trip
  // -----------------------------------------------

  if (data.faultCode != 0) {

    data.tripped = true;

    digitalWrite(
        TRIP_RELAY_PIN,
        HIGH);

    digitalWrite(
        ALARM_RELAY_PIN,
        HIGH);
  }
}

// =====================================================
// ThingSpeak upload
// =====================================================

void sendThingSpeak() {

  if (WiFi.status() != WL_CONNECTED)
    return;

  HTTPClient http;

  String url =
      String(THINGSPEAK_URL) +
      "?api_key=" +
      THINGSPEAK_API_KEY +

      "&field1=" +
      String(data.voltageR, 2) +

      "&field2=" +
      String(data.voltageY, 2) +

      "&field3=" +
      String(data.voltageB, 2) +

      "&field4=" +
      String(data.currentR, 2) +

      "&field5=" +
      String(data.currentY, 2) +

      "&field6=" +
      String(data.currentB, 2) +

      "&field7=" +
      String(data.temperature, 2) +

      "&field8=" +
      String(data.faultCode);

  http.begin(url);

  int response =
      http.GET();

  Serial.print(
      "ThingSpeak response: ");

  Serial.println(response);

  http.end();
}

// =====================================================
// Send JSON to n8n
// =====================================================

void sendN8N() {

  if (WiFi.status() != WL_CONNECTED)
    return;

  HTTPClient http;

  http.begin(N8N_WEBHOOK);

  http.addHeader(
      "Content-Type",
      "application/json");

  StaticJsonDocument<1024> doc;

  doc["device"] = "TX-001";

  doc["voltage_r"] =
      data.voltageR;

  doc["voltage_y"] =
      data.voltageY;

  doc["voltage_b"] =
      data.voltageB;

  doc["current_r"] =
      data.currentR;

  doc["current_y"] =
      data.currentY;

  doc["current_b"] =
      data.currentB;

  doc["temperature"] =
      data.temperature;

  doc["voltage_imbalance"] =
      data.voltageImbalance;

  doc["current_imbalance"] =
      data.currentImbalance;

  doc["fault_code"] =
      data.faultCode;

  doc["tripped"] =
      data.tripped;

  doc["status"] =
      data.tripped ?
      "TRIP" :
      "NORMAL";

  String payload;

  serializeJson(
      doc,
      payload);

  int response =
      http.POST(payload);

  Serial.print(
      "n8n response: ");

  Serial.println(response);

  http.end();
}

// =====================================================
// Reset protection
// =====================================================

void checkReset() {

  if (
      digitalRead(RESET_PIN) == HIGH
  ) {

    // Only allow reset when
    // conditions are safe.

    readSensors();

    if (
        data.temperature <
        TEMPERATURE_WARNING &&

        data.currentR <
        MAX_CURRENT * 0.8 &&

        data.currentY <
        MAX_CURRENT * 0.8 &&

        data.currentB <
        MAX_CURRENT * 0.8
    ) {

      data.tripped = false;
      data.faultCode = 0;

      digitalWrite(
          TRIP_RELAY_PIN,
          LOW);

      digitalWrite(
          ALARM_RELAY_PIN,
          LOW);
    }
  }
}

// =====================================================
// Setup
// =====================================================

void setup() {

  Serial.begin(115200);

  pinMode(
      TRIP_RELAY_PIN,
      OUTPUT);

  pinMode(
      ALARM_RELAY_PIN,
      OUTPUT);

  pinMode(
      CONTACTOR_FB_PIN,
      INPUT);

  pinMode(
      RESET_PIN,
      INPUT);

  digitalWrite(
      TRIP_RELAY_PIN,
      LOW);

  digitalWrite(
      ALARM_RELAY_PIN,
      LOW);

  temperatureSensor.begin();

  WiFi.begin(
      WIFI_SSID,
      WIFI_PASSWORD);

  Serial.print(
      "Connecting to Wi-Fi");

  while (
      WiFi.status() != WL_CONNECTED
  ) {

    delay(500);

    Serial.print(".");
  }

  Serial.println();

  Serial.print(
      "IP address: ");

  Serial.println(
      WiFi.localIP());
}

// =====================================================
// Main loop
// =====================================================

void loop() {

  readSensors();

  protectionCheck();

  checkReset();

  Serial.println(
      "-----------------------------");

  Serial.print("VR: ");
  Serial.println(data.voltageR);

  Serial.print("VY: ");
  Serial.println(data.voltageY);

  Serial.print("VB: ");
  Serial.println(data.voltageB);

  Serial.print("IR: ");
  Serial.println(data.currentR);

  Serial.print("IY: ");
  Serial.println(data.currentY);

  Serial.print("IB: ");
  Serial.println(data.currentB);

  Serial.print("Temperature: ");
  Serial.println(data.temperature);

  Serial.print("Fault: ");
  Serial.println(data.faultCode);

  if (
      millis() -
      lastCloudUpdate >=
      CLOUD_INTERVAL
  ) {

    sendThingSpeak();

    sendN8N();

    lastCloudUpdate =
        millis();
  }

  delay(1000);
}

Espressif documents the Wi-Fi station mode used by this type of ESP32 firmware. 


24. Important Improvement: RMS Measurement

For a serious three-phase monitoring project, don't simply convert one ADC average directly into voltage.

AC measurement should preferably use:

AC waveform
     ↓
Sampling
     ↓
Remove DC offset
     ↓
Square samples
     ↓
Average
     ↓
Square root
     ↓
RMS

Mathematically:

VRMS=1N∑n=1NVn2

Similarly:

IRMS=1N∑n=1NIn2

This gives a much better monitoring system.


25. Improved RMS Function

For a suitably conditioned isolated AC sensor:

float calculateRMS(
    int pin,
    float adcOffset,
    float calibration)
{
    const int samples = 1000;

    double sumSquares = 0;

    for (int i = 0; i < samples; i++)
    {
        float raw = analogRead(pin);

        float value =
            raw - adcOffset;

        sumSquares +=
            value * value;

        delayMicroseconds(100);
    }

    float rmsADC =
        sqrt(sumSquares / samples);

    return rmsADC * calibration;
}

The adcOffset and calibration values must be experimentally obtained from the actual sensing circuit.


26. n8n Webhook Payload

Configure the Webhook node to receive:

{
  "device": "TX-001",
  "voltage_r": 230.2,
  "voltage_y": 231.0,
  "voltage_b": 229.8,
  "current_r": 4.2,
  "current_y": 4.4,
  "current_b": 4.1,
  "temperature": 54.2,
  "fault_code": 0,
  "status": "NORMAL"
}

Then create an n8n flow:

Webhook
   ↓
Code/Set
   ↓
Google Sheets
   ↓
Switch
   ├── NORMAL → END
   │
   └── FAULT
          ↓
       AI Agent
          ↓
      Alert Text
          ↓
       Telegram
          ↓
     Text-to-Speech
          ↓
     Telegram Voice

27. AI Prompt for n8n

A useful system prompt for the AI Agent is:

You are an industrial transformer monitoring assistant.

Your task is to analyze telemetry from a three-phase
transformer.

Never claim that the transformer is safe unless the
measured values support that conclusion.

Never override or bypass a local protection trip.

Local ESP32 protection has priority over all AI decisions.

Analyze:

- Three-phase voltage
- Three-phase current
- Temperature
- Voltage imbalance
- Current imbalance
- Fault code
- Trip state

Classify the condition as:

NORMAL
WARNING
CRITICAL
TRIPPED

For a fault:

1. Identify the most significant abnormal parameter.
2. Compare it with the configured threshold.
3. Explain the likely condition.
4. Recommend inspection steps.
5. Clearly state that physical inspection is required
   before re-energization after a trip.

Return concise output suitable for Telegram.

28. AI Agent Tools

The agent can eventually have tools such as:

AI Agent
│
├── get_current_status()
│
├── get_last_10_readings()
│
├── get_fault_history()
│
├── get_temperature_trend()
│
├── get_current_trend()
│
├── get_voltage_trend()
│
├── create_maintenance_report()
│
└── send_operator_notification()

A more advanced version could query ThingSpeak's REST API for historical data. ThingSpeak supports reading channel and field data through its REST API. 


29. Example AI Conversation

Operator

/status

AI Agent

Transformer TX-001

Status: NORMAL 🟢

R voltage: 230.4 V
Y voltage: 229.8 V
B voltage: 231.1 V

R current: 4.2 A
Y current: 4.1 A
B current: 4.3 A

Temperature: 52.6 °C

Voltage imbalance: 0.57%
Current imbalance: 4.76%

No active protection fault.

Operator

Why did TX-001 trip?

AI

TX-001 tripped at 14:32.

The primary trip condition was overtemperature.

Temperature:
87.4 °C

The temperature increased together with phase
current, suggesting that transformer loading may
have contributed.

Recommended checks:

1. Check transformer loading.
2. Check cooling/ventilation.
3. Inspect connections.
4. Review current trend.
5. Do not re-energize until the cause is verified.

30. Voice Alert

The n8n flow can convert the AI response to audio:

AI response
     ↓
Text-to-Speech
     ↓
MP3/voice-compatible audio
     ↓
Telegram

Telegram's Bot API specifically distinguishes ordinary audio from the sendVoice method intended for voice messages. 


31. Telegram Command Architecture

Recommended commands:

/status
/voltage
/current
/temperature
/history
/fault
/report
/reset
/help

Example:

User:
 /temperature

AI:
TX-001 temperature = 54.7°C
Status = NORMAL
Warning threshold = 70°C
Trip threshold = 85°C

32. Remote Reset Security

I strongly recommend:

Telegram /reset
       ↓
AI
       ↓
Safety validation
       ↓
Is transformer locally safe?
       ↓
    ┌───────┐
    │       │
   NO      YES
    │       │
    ↓       ↓
Reject    Request
          authorized
          reset
             ↓
       Local ESP32
             ↓
       Interlock check
             ↓
        Reset allowed

Do not make:

Telegram /reset
       ↓
ESP32 relay ON

because that bypasses physical safety.


33. Schematic — Conceptual

                   THREE-PHASE TRANSFORMER
                 ┌────────────────────────┐
                 │                        │
      PHASE R ───┤                        │
      PHASE Y ───┤      TRANSFORMER       │
      PHASE B ───┤                        │
                 │                        │
                 └────────────────────────┘
                    │       │       │
                    │       │       │
                   CT-R    CT-Y    CT-B
                    │       │       │
                    ↓       ↓       ↓
                ┌─────────────────────────┐
                │ Current Signal           │
                │ Conditioning / Isolation │
                └────────────┬────────────┘
                             │
                             ↓
                       ESP32 ADC
                             │
                             │
      R Voltage ──[ISOLATED VOLTAGE SENSOR]──→ ADC
      Y Voltage ──[ISOLATED VOLTAGE SENSOR]──→ ADC
      B Voltage ──[ISOLATED VOLTAGE SENSOR]──→ ADC
                             │
                             ↓
                     ┌─────────────┐
                     │    ESP32    │
                     │             │
                     │ ADC         │
                     │ Protection  │
                     │ Wi-Fi       │
                     └──────┬──────┘
                            │
                  ┌─────────┴─────────┐
                  │                   │
                  ↓                   ↓
             Trip Relay          Wi-Fi Router
                  │                   │
                  ↓                   ↓
             Contactor          Internet/Cloud
                                      │
                     ┌────────────────┼──────────────┐
                     ↓                ↓              ↓
                 ThingSpeak          n8n         Dashboard
                                      │
                           ┌──────────┼──────────┐
                           ↓          ↓          ↓
                         AI       Telegram    Sheets

34. Relay/Contactor Protection

Conceptually:

ESP32 GPIO
    │
    ↓
Transistor/MOSFET driver
    │
    ↓
Relay coil
    │
    ↓
Interposing relay
    │
    ↓
Contactor/trip circuit
    │
    ↓
Transformer isolation

For an actual electrical installation, the contactor/trip circuit should be engineered independently and appropriately rated.

The ESP32 should not directly drive a large contactor coil.


35. Local Web Server

The ESP32 can also expose a local page:

http://ESP32-IP/

Example:

ESP32 LOCAL DASHBOARD

Transformer: TX-001

Status: NORMAL

Voltage:
R = 230 V
Y = 231 V
B = 229 V

Current:
R = 4.2 A
Y = 4.1 A
B = 4.3 A

Temperature = 52°C

Wi-Fi = Connected

ThingSpeak = OK

n8n = OK

ESP32 Wi-Fi station mode supports connecting to an access point for Internet-connected applications. 


36. Complete Data Flow

                  TRANSFORMER
                       │
                       ↓
                    Sensors
                       │
                       ↓
                    ESP32
                       │
        ┌──────────────┼──────────────┐
        │              │              │
        ↓              ↓              ↓
   Protection       ThingSpeak       n8n
        │              │              │
        ↓              ↓              ↓
    Trip Relay     Cloud Graph      AI Agent
                                      │
                           ┌──────────┼──────────┐
                           │          │          │
                           ↓          ↓          ↓
                       Analysis   Telegram    Sheets
                                      │
                           ┌──────────┴──────────┐
                           ↓                     ↓
                       Text Alert            Voice Alert

37. Fault Codes

Define a fixed fault-code table:

0 = NORMAL

1 = OVERVOLTAGE

2 = UNDERVOLTAGE

3 = OVERCURRENT

4 = OVERTEMPERATURE

5 = VOLTAGE_IMBALANCE

6 = CURRENT_IMBALANCE

7 = SENSOR_FAILURE

8 = CONTACTOR_FAILURE

9 = ESP32_COMMUNICATION_FAILURE

10 = MULTIPLE_FAULT

For multiple simultaneous faults, send a bitmask or a fault array rather than allowing one fault to overwrite another.

For example:

{
  "faults": [
    "OVERCURRENT",
    "OVERTEMPERATURE"
  ]
}

38. Sensor Failure Detection

This is a very important addition.

Suppose the current sensor suddenly reports:

0 A

while the transformer is known to be energized.

The system shouldn't blindly assume the current is zero.

Implement:

Sensor reading
      ↓
Plausibility check
      ↓
Valid?
 ┌────┴────┐
YES        NO
 │          │
 ↓          ↓
Normal    SENSOR FAULT

Examples:

ADC saturated
Negative impossible value
Disconnected sensor
Constant frozen value
Unexpected zero
Out-of-range value

39. Communication Failure Handling

If Internet fails:

Internet lost
     ↓
ESP32 continues
     ↓
Protection continues
     ↓
Local alarm continues
     ↓
Data buffered locally
     ↓
Internet restored
     ↓
Upload buffered data

Never design the protection system so that:

Wi-Fi OFF → Transformer protection OFF

40. Cloud Failure Handling

Similarly:

ThingSpeak unavailable
       ↓
Local protection continues
       ↓
n8n may still receive data
       ↓
Dashboard shows cloud fault

The system should have health indicators:

ESP32       🟢
Sensors     🟢
Wi-Fi       🟢
ThingSpeak  🟢
n8n         🟢
Telegram    🟢
AI Agent    🟢

41. ThingSpeak Dashboard

Recommended charts:

Chart 1:
Three-phase voltage

Chart 2:
Three-phase current

Chart 3:
Transformer temperature

Chart 4:
Voltage imbalance

Chart 5:
Current imbalance

Chart 6:
Fault code

Chart 7:
Load trend

ThingSpeak is specifically designed to aggregate, visualize and analyze live IoT data streams. 


42. Project Operating Modes

Implement four modes:

NORMAL
WARNING
TRIPPED
MAINTENANCE

NORMAL

Everything within limits.

WARNING

Parameter approaching limit.

TRIPPED

Unsafe condition detected.

MAINTENANCE

Protection temporarily controlled under authorized maintenance procedures.


43. Example Warning

⚠️ TRANSFORMER WARNING

Device: TX-001

Temperature: 72.1°C

Warning limit: 70°C
Trip limit: 85°C

Current:
R = 8.8 A
Y = 8.6 A
B = 8.9 A

Recommendation:
Inspect loading and cooling conditions.

44. Example Critical Alert

🚨 CRITICAL TRANSFORMER FAULT

Device: TX-001

Fault: OVERTEMPERATURE

Temperature: 87.3°C

Trip status: ACTIVE

The local protection controller has isolated
the transformer.

Do not re-energize until the cause is inspected.

45. Google Sheets Database Design

Create columns:

Timestamp
Device_ID
Voltage_R
Voltage_Y
Voltage_B
Current_R
Current_Y
Current_B
Temperature
Frequency
Voltage_Imbalance
Current_Imbalance
Fault_Code
Status
Trip_State
AI_Severity
AI_Diagnosis
Action
Operator

This becomes your maintenance database.


46. AI Maintenance Prediction

Once sufficient historical data exists, the AI can identify patterns.

Example:

Week 1:
Temperature = 48°C

Week 2:
Temperature = 54°C

Week 3:
Temperature = 61°C

Week 4:
Temperature = 69°C

AI:

Temperature trend is increasing.

The transformer has shown a gradual increase
in operating temperature over the last four weeks.

Suggested maintenance:
Inspect cooling system and loading conditions.

This is more useful than simple threshold alarms.


47. Agentic Predictive Maintenance

Eventually:

Historical Data
       ↓
ThingSpeak
       ↓
n8n
       ↓
AI Agent
       ↓
Trend Analysis
       ↓
Risk Score
       ↓
Maintenance Recommendation
       ↓
Telegram

Example:

TX-001 Maintenance Risk

Temperature trend: HIGH
Current trend: MEDIUM
Voltage imbalance: LOW

Overall risk: MEDIUM

Recommended:
Cooling-system inspection within maintenance window.

48. Suggested Project Modules

For a final-year engineering project, divide the project into:

Module 1 — Transformer sensing

Measure:

V_R
V_Y
V_B
I_R
I_Y
I_B
Temperature

Module 2 — ESP32 processing

ADC
RMS
Filtering
Calibration
Fault detection

Module 3 — Local protection

Overvoltage
Undervoltage
Overcurrent
Overtemperature
Imbalance
Trip

Module 4 — IoT

Wi-Fi
ThingSpeak
n8n

Module 5 — Web dashboard

Live values
Graphs
Fault history
Device status

Module 6 — AI Agent

Diagnosis
Trend analysis
Natural-language queries
Maintenance recommendations

Module 7 — Notifications

Telegram
Text
Voice

Module 8 — Data logging

Google Sheets
Fault history
Maintenance history

49. Project Development Sequence

Don't build everything simultaneously.

Follow this sequence:

STEP 1
ESP32 basic programming
        ↓
STEP 2
Read temperature
        ↓
STEP 3
Read one voltage sensor
        ↓
STEP 4
Read one current sensor
        ↓
STEP 5
Add three-phase measurements
        ↓
STEP 6
Calibration
        ↓
STEP 7
RMS calculations
        ↓
STEP 8
Protection algorithm
        ↓
STEP 9
Relay/trip simulation
        ↓
STEP 10
Wi-Fi
        ↓
STEP 11
ThingSpeak
        ↓
STEP 12
n8n Webhook
        ↓
STEP 13
Google Sheets
        ↓
STEP 14
Telegram
        ↓
STEP 15
Voice notification
        ↓
STEP 16
AI Agent
        ↓
STEP 17
Web dashboard
        ↓
STEP 18
Complete integration

50. Testing Plan

Test 1 — Normal operation

VR = 230 V
VY = 230 V
VB = 230 V

IR = 4 A
IY = 4 A
IB = 4 A

Temperature = 45°C

Expected:

Status = NORMAL
Trip = OFF

Test 2 — Overtemperature

Temperature = 87°C

Expected:

Fault = OVERTEMPERATURE
Trip = ON
Telegram = ALERT
Google Sheets = LOG
AI = ANALYSIS

Test 3 — Overcurrent

IR = 12 A

Expected:

Fault = OVERCURRENT
Trip = ON

Test 4 — Voltage imbalance

VR = 230
VY = 220
VB = 230

Expected:

Voltage imbalance detected

Test 5 — Wi-Fi failure

Turn off Wi-Fi.

Expected:

Protection continues
Trip continues to work
Local alarms continue

Test 6 — n8n failure

Stop n8n.

Expected:

ESP32 protection continues

Test 7 — ThingSpeak failure

Expected:

Local protection continues

51. Final Demonstration Scenario

For your project demonstration:

SYSTEM START
     ↓
ESP32 connects to Wi-Fi
     ↓
Dashboard shows NORMAL
     ↓
ThingSpeak receives measurements
     ↓
Google Sheets logs data
     ↓
Simulate increasing load
     ↓
Current rises
     ↓
Temperature rises
     ↓
ESP32 detects fault
     ↓
Trip output activates
     ↓
ESP32 sends JSON to n8n
     ↓
n8n logs event
     ↓
AI Agent analyzes fault
     ↓
Telegram text alert
     ↓
Text-to-Speech
     ↓
Telegram voice alert
     ↓
Operator receives notification

That makes a very strong project demonstration because it shows the complete edge → cloud → automation → AI → human chain.


52. Overall System Diagram for Your Report

                         ┌───────────────────┐
                         │  THREE-PHASE TX   │
                         └─────────┬─────────┘
                                   │
                ┌──────────────────┼──────────────────┐
                │                  │                  │
             Voltage             Current          Temperature
             Sensors             Sensors             Sensor
                │                  │                  │
                └──────────────────┼──────────────────┘
                                   │
                                   ↓
                         ┌───────────────────┐
                         │       ESP32       │
                         │                   │
                         │ Data Acquisition  │
                         │ RMS Calculation   │
                         │ Filtering         │
                         │ Fault Detection   │
                         │ Protection        │
                         │ Wi-Fi             │
                         └───────┬─────┬─────┘
                                 │     │
                         Trip ───┘     │
                                       │
                                       ↓
                              ┌─────────────────┐
                              │   Internet      │
                              └──────┬──────────┘
                                     │
                    ┌────────────────┼────────────────┐
                    │                │                │
                    ↓                ↓                ↓
              ThingSpeak           n8n             Web App
                    │                │
                    │         ┌──────┴────────┐
                    │         │               │
                    │         ↓               ↓
                    │       AI Agent       Automation
                    │         │               │
                    │         ├──────┬────────┤
                    │         ↓      ↓        ↓
                    │     Telegram  Voice   Sheets
                    │
                    ↓
              Cloud Charts

53. Software Stack

Layer Technology
Microcontroller ESP32
Firmware Arduino/C++
Connectivity Wi-Fi
IoT cloud ThingSpeak
Automation n8n
AI LLM/AI Agent
Notification Telegram Bot
Voice Text-to-Speech
Database/log Google Sheets
Web dashboard HTML/CSS/JavaScript
API HTTP/REST
Data format JSON

ESP32's current Arduino documentation provides the underlying Wi-Fi and peripheral APIs needed for the firmware layer. 


54. Security Requirements

Do not put credentials directly into a public GitHub repository.

Use:

Wi-Fi password       → secret
ThingSpeak Write Key → secret
n8n webhook URL      → protected
Telegram Bot Token   → secret
Google credentials   → n8n credential store
AI API key           → n8n credential store

ThingSpeak's Write API Key controls channel writes, so it should be treated as a credential. 

Also use:

  • HTTPS
  • Authentication on custom APIs
  • Device IDs
  • Webhook secrets
  • Rate limiting
  • Telegram user authorization
  • n8n credential storage
  • No unrestricted remote trip/reset commands

55. Final Project Objectives

The project objectives can be written as:

  1. To design a real-time three-phase transformer monitoring system.
  2. To measure phase voltage and current using isolated sensing circuits.
  3. To monitor transformer temperature continuously.
  4. To calculate electrical parameter imbalance.
  5. To implement local protection using ESP32.
  6. To detect abnormal transformer operating conditions.
  7. To transmit telemetry to ThingSpeak.
  8. To develop a web-based IoT dashboard.
  9. To integrate n8n for workflow automation.
  10. To log transformer events in Google Sheets.
  11. To provide Telegram text notifications.
  12. To provide Telegram voice notifications.
  13. To implement an AI agent for fault interpretation.
  14. To provide historical and predictive maintenance analysis.
  15. To maintain local protection even during cloud/network failure.

56. Expected Results

The completed system should provide:

                    EXPECTED OUTPUT

                 ┌───────────────────┐
                 │ TRANSFORMER       │
                 │ MONITORING        │
                 └─────────┬─────────┘
                           ↓
             ┌─────────────────────────┐
             │ Real-time measurements  │
             └────────────┬────────────┘
                          ↓
                     ESP32
                          ↓
               ┌──────────┴──────────┐
               ↓                     ↓
          LOCAL TRIP             IoT DATA
               │                     │
               ↓                     ↓
        Transformer safe       ThingSpeak
                                     │
                                     ↓
                                    n8n
                                     │
                    ┌────────────────┼──────────────┐
                    ↓                ↓              ↓
                   AI             Telegram       Sheets
                    │                │              │
                    ↓                ↓              ↓
              Diagnosis         Text/Voice      History

57. Important Engineering Limitation

This architecture is excellent for a prototype, academic project, laboratory demonstrator, or non-safety-critical monitoring system.

For an actual utility/industrial transformer protection installation, an ESP32 + cloud/AI system should not replace certified transformer protection equipment. Protection such as overcurrent, differential, earth fault, temperature, breaker trip circuits, interlocks and emergency systems should be engineered using appropriate industrial protection hardware and standards.

The AI component should be treated as decision support and maintenance intelligence, not as the primary protection relay.


58. Recommended Final Project Name

For a university report, I would use:

“Design and Implementation of an IoT-Based Three-Phase Transformer Monitoring and Protection System Using ESP32 with ThingSpeak, n8n Automation, AI-Agentic Fault Analysis, Telegram Voice Alerts and Cloud Dashboard”

That title captures essentially the whole architecture without making the project sound like only a simple ESP32 sensor project.

Useful official documentation

If you are turning this into a final-year project report, the next logical step is to convert this architecture into a formal Chapter 1–10 project document with abstract, literature survey, block diagram, circuit/schematic, component specifications, mathematical calculations, ESP32 source code, n8n workflow design, AI-agent prompt, Telegram setup, Google Sheets setup, ThingSpeak setup, testing tables, results, conclusion, future scope, references, and viva questions/answers.