Croaster is a lightweight, open-source temperature monitoring system built on ESP-based microcontrollers. Designed for coffee roasting, it reads from two thermocouple sensors and displays real-time data on an OLED screen. Croaster also provides connectivity via WiFi (ESP8266/ESP32) and BLE (ESP32 only) for remote monitoring and control.

• Supports NodeMCU ESP8266 (WiFi only)
• Supports ESP32C3 Super Mini (WiFi & BLE)
• Real-time monitoring of two MAX6675 sensors (ET and BT)
• Visual output on a 128x64 OLED display (SSD1306, I2C)
• WiFi communication via WebSocket, compatible with:
  • Artisan Roaster Scope
  • ICRM app
• BLE communication (ESP32 only) for the ICRM app
• Custom command system via a centralized CommandHandler class
• Easily extendable with user-defined commands

• 1× NodeMCU ESP8266 or ESP32C3 Super Mini
• 1× 128x64 OLED display (SSD1306, I2C)
• 2× MAX6675 thermocouple sensor modules
• 2× K-type thermocouple probes

• Written in C++ with the PlatformIO build system
• Modular architecture separating BLE, WebSocket, display, and sensor logic
• CommandHandler class:
  • Manages all incoming BLE/WebSocket JSON commands
  • Easily customizable for user-defined actions (e.g. restart, erase, etc.)

1. Install PlatformIO
2. Clone the repository:

   git clone [email protected]:IiemB/Croaster.git
   cd croaster

3. Select your board in platformio.ini (ESP8266 only)
4. Upload the firmware:

   pio run -t upload

1. Run the conversion script:

   ./copy_to_ino.sh

2. Open croaster-arduino folder in Arduino IDE

3. Select your board:

   • ESP8266 → NodeMCU 1.0 (ESP-12E)
   • ESP32C3 → Makergo ESP32C3 (ESP32C3 Super Mini is not yet supported by PlatformIO)

4. Select partition Huge APP (ESP32C3 only)

   [!NOTE] this partition doesn't support OTA via ICRM App. To handle this, you can follow this steps.

To connect Croaster to your WiFi network, you can follow this quick video guide: ➡️ How to Connect to WiFi - YouTube

• WebSocket (WiFi):

  • Connects with Artisan Roaster Scope
  • Also supports the ICRM app (Android only)

• BLE (ESP32 only):

  • Connects exclusively with the ICRM app (Android only)

You can connect your Croaster device to Artisan using either a direct WiFi connection or through your home/local WiFi network.

1. On your computer, connect to the WiFi network broadcasted by your Croaster device. (It will appear as something like [XXXX] Croaster-XXXX)
2. Open Artisan, go to Config → Port.
3. Set the configuration as shown below:

If your Croaster is already connected to your home WiFi, and your laptop is on the same network:

1. Open Artisan, go to Config → Port.
2. Enter the IP address assigned to Croaster (you can find this on the Croaster OLED screen or serial log).
3. Use the configuration shown here:

MIT License — free for personal and commercial use. Contributions welcome!

Pull requests and feedback are welcome!