Imported from GitHub: Mounith-H/Portable_temperature_sensor · commit 4736d76 · license MIT

Description

wireless IoT temperature monitoring device based on the ESP8266 NodeMCU platform. It uses a MAX6675 thermocouple interface to measure temperatures up to 1024°C with high precision, making it suitable for industrial monitoring, cooking, 3D printing, and scientific applications.

README

Portable Temperature Sensor

Overview

The Portable Temperature Sensor is a wireless IoT temperature monitoring device based on the ESP8266 NodeMCU platform. It uses a MAX6675 thermocouple interface to measure temperatures up to 1024°C with high precision, making it suitable for industrial monitoring, cooking, 3D printing, and scientific applications.

Key Features

• High-Temperature Measurement: Uses the MAX6675 thermocouple for accurate measurements up to 1024°C
• Wireless Connectivity: Built-in WiFi for remote monitoring and control
• MQTT Support: Integrates with home automation systems and custom dashboards
• Alarm System: Configurable temperature thresholds with buzzer alerts
• Interrupt Output: Provides digital signal output when temperature exceeds thresholds
• Custom PCB Design: Optimized layout with full KiCad design files
• Serial Communication: Both USB and software serial interfaces for flexible integration

Hardware Components

• NodeMCU ESP8266 - Main controller with WiFi capability
• MAX6675 Module - K-type thermocouple interface
• K-Type Thermocouple - High-temperature sensing element
• Buzzer - For audible alerts
• Passive Components - Resistors, capacitors for circuit stability

Pin Connections

Pin Numbers	Pin Names	Pin Function	Other	Connection
ADC0	A0	Analog Input	X	X
GPIO16	D0	WAKE	X	SEN-CS
GPIO5	D1	SCL	X	OLED/ SCL
GPIO4	D2	SDA	X	OLED/ SDA
GPIO0	D3	FLASH	Pull-up	BUZZER
GPIO2	D4	TXD1/LED	Pull-up	INTERRUPT
GPIO14	D5	SCLK	X	SEN-SCK
GPIO12	D6	MISO	X	SEN-SO
GPIO13	D7	MOSI/RXD2	X	UART-RX
GPIO15	D8	CS/TXD2	Pull-down	UART-TX
GPIO3	RX	RXD0	X	X
GPIO1	TX	TXD0	X	X
RST	RST	Reset	Pull-up	X

Software Setup

Prerequisites

• PlatformIO (recommended) or Arduino IDE
• Required libraries:
  • PubSubClient for MQTT
  • EspSoftwareSerial for additional serial ports
  • Adafruit MAX6675 for thermocouple interface
  • GyverOLED for display support (optional - will be implemented separately)

Installation

1. Clone this repository:

   git clone https://github.com/MOUNITH-H/Portable_temperature_sensor.git
   

2. Open the project in PlatformIO or Arduino IDE:

   • For PlatformIO: Open the Portable_temperature_sensor folder
   • For Arduino IDE: Open src/main.cpp as your sketch

3. Configure WiFi and MQTT settings:

   • Edit the connection parameters in main.cpp

4. Build and upload to your NodeMCU

PCB Design

The project includes a custom PCB design created with KiCad. The design files are in the pcb folder:

• Full schematic in pcb.kicad_sch
• PCB layout in pcb.kicad_pcb
• Interactive BOM available in pcb/bom/ibom.html

Usage

1. Power the device using USB or a 5V power source
2. The device will automatically connect to the configured WiFi network
3. Temperature data is published to the MQTT topic portable_temp_sensor/temperature
4. The buzzer will sound if the temperature exceeds the configured threshold
5. Configure alarm settings via the MQTT topic portable_temp_sensor/settings

MQTT Topics

Topic	Description	Message Format
portable_temp_sensor/temperature	Current temperature readings	{"temp": 25.4, "timestamp": 1620123456}
portable_temp_sensor/settings	Device configuration	{"threshold": 80, "buzzer_enabled": true}
portable_temp_sensor/status	Device status information	{"uptime": 3600, "wifi_strength": -67}

Troubleshooting

• No temperature readings: Check thermocouple connections
• Cannot connect to WiFi: Verify credentials in the code
• MQTT connection issues: Confirm server address and port settings
• Erratic readings: Check for interference with thermocouple wires

TODO

• Convert to FreeRTOS

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Author

• MOUNITH H - Initial work