Temperature Chamber

The Temperature Chamber is a complete system for benchmark testing and stress-testing electronic boards in a controlled thermal environment. It combines accessible hardware, advanced firmware, and a Python-based desktop application to achieve precise temperature control, test execution, and real-time monitoring. The system is designed to standardize thermal testing while prioritizing accessibility and replicability with cost-effective, off-the-shelf components.

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Hardware

Components

• Case: Case sorced from a music instrument.
• Insulation: Natural cork for temperature insulation.
• Heating Element: Ceramic heating element for precise temperature control.
• Cooling System: Air-blower sourced from an inflatable mattress, featuring airflow shutoff when inactive.
• Temperature Sensors: Two 1-wire thermocouple sensors for accurate temperature measurement.
• Control System:
  • Arduino Uno R4 WiFi board for managing system operations.
  • Custom PCB shield with solid-state relays for heater and blower control.
  • Buttons and switches for manual operation.
  • LCD display for showing system status, temperature data, and current temperature goal.

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Firmware

The firmware manages the chamber's operation, focusing on safety, precision, and flexibility. Key features include:

State Machine

The firmware operates via a state machine with the following states:

• HEATING: Activates the heater to raise the temperature.
• COOLING: Activates the blower to lower the temperature.
• IDLE: Chamber stays in idle mode until a condition is met or further input is provided.
• EVALUATE: Evaluates whether to go into COOLING or HEATING state based on temperature.
• EMERGENCY_STOP: Shuts down operations until the start switch is switched on.

Test Execution

The chamber supports:

• Running predefined and custom tests.
• Queueing multiple tests with parameters such as temperature and duration
• Real-time monitoring of test progress.

Communication protocol

The firmware communicates with the desktop application via a JSON-based protocol, enabling:

• Remote control of the chamber.
• Sending and receiving commands like PING, RESET, SET_TEMP, and RUN_QUEUE.
• Handshake and ping for connection validation and error handling.
• Real-time feedback on test status, temperature, and machine state.

See docs for more information.

Error handling

• Timeout mechanisms to reset and cool down the chamber after prolonged connection loss.
• Safety measures for exceeding temperature limits.

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Desktop application

The Python-based desktop application provides an intuitive interface to interact with the chamber:

Features

• Real-time Monitoring: View the current temperature, test progress, and machine state.
• Queue Management: Upload JSON test configurations, manage test queues, and clear tests.
• Manual Control: Set temperature and duration manually, overriding queued tests.
• Wifi Boards: Option to connect a microcontroller with Wifi capabilities to test the Wifi performance of microcontrollers being tested.
• Error Notifications: Alerts for connection issues, emergency stops, and test interruptions.
• Logging: Detailed logs for debugging and analysis.

Installation

1. Clone the repository:

git clone https://github.com/defliez/temperature_chamber.git
cd temperature_chamber

2. Install the dependencies:

pip install pyqt5 python-dateutil pyserial

Usage

1. Run the application:

python3 interface/pyqt5/t-chamber/main.py

2. Using the GUI:

• Select the control and test board ports.
• Click refresh to update the connected ports in case of disconnection.
• Click the Start button to establish serial connection with the boards.
• Enter the Queue tab to queue tests, see the current queued tests and clear the test queue.
• Enter the Manual tab to manually set the temperature and duration, overriding potential running tests.
• Enter the Running test info tab to view:
  • Status updates from the chamber.
  • Expected output and real-time actual output from the test board.
  • An overview of the current test and sequence status, including:
  • Current test name.
  • Amount of sequences in the current test.
  • Remaining time of the running sequence.
  • Total amount of sequences across all queued tests (visualized with segmented progress bar).
  • Estimated running time of queued tests, taking into account the set durations for the sequences as well as the time to heat up and cool down the chamber between sequences.
• Press reset control board to clear all tests in the queue, interrupt the current running test, and put the Temperature Chamber into an idle state.

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Safety measures

• Temperature Thresholds: Prevents the chamber from exceeding 100°C. This limit can be temporarily overridden.
• Ping Mechanism: Ensures continuous connection between the chamber and application.
• Emergency Stop: Resets and cools down the chamber after 5 minutes of no ping response.

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Acknowledgments:

• Adam Harb:
  • Hardware design, the custom shield, and the original state machine implementation.
• Valentino Glave:
  • Enhanced the firmware with JSON-based communication for remote control and monitoring.
  • Modernized and optimized the state machine for advanced test handling.
  • Integrated remote control on firmware side.
  • Implemented functionality and UI components to allow connection to a Wifi board.
  • Refactored UI to enhance responsiveness.
  • Integrated robust error handling and logging.
  • Enhanced workflows.
• Owen Kraus:
  • Created an intuitive and functional Python application.
  • Developed infrastructure to communicate with, and display output from the chamber.
  • Implemented robust error handling and logging.

For inquiries or further development, please contact via the provided channels.

Authors:

• Valentino Glave, valentinoglave@protonmail.com
• Owen Kraus, owenkraus9@gmail.com
• Adam Harb, adam.harb@hotmail.com
• David Cuartielles, d.cuartielles@arduino.cc

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