IoT-For-Beginners/TROUBLESHOOTING.md

Troubleshooting Guide

This guide helps you solve common problems when working with the IoT for Beginners curriculum. Issues are organized by category for easy navigation.

Table of Contents

• Installation Issues
  • Python Installation
  • VS Code and Extensions
  • PlatformIO (Wio Terminal)
  • Grove Libraries
• Hardware Issues
  • Raspberry Pi
  • Wio Terminal
  • Virtual Device (CounterFit)
• Connectivity Issues
  • WiFi Connection
  • Cloud Services
  • MQTT
• Sensor and Actuator Issues
  • Grove Sensors
  • Camera
  • Microphone and Speaker
• Development Environment Issues
  • VS Code
  • Python Virtual Environments
  • Dependencies
• Performance Issues
• Common Error Messages
• Getting Help

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Installation Issues

Python Installation

Problem: Python version is too old

Error: Python 3.6 or higher is required

Solution:

1. Download the latest Python 3 from python.org
2. During installation on Windows, check "Add Python to PATH"
3. Verify installation:

   python3 --version
   

Problem: Multiple Python versions causing conflicts

Symptoms: Wrong Python version runs, packages install to wrong location

Solution:

• Windows: Use py -3 instead of python to explicitly call Python 3
• macOS/Linux: Use python3 instead of python
• Always create and use virtual environments for projects

Problem: pip command not found

Error: 'pip' is not recognized as an internal or external command

Solution:

1. Try pip3 instead of pip
2. Or use python -m pip or python3 -m pip
3. Ensure Python is added to PATH (reinstall Python and check the option)

VS Code and Extensions

Problem: Pylance extension not working

Symptoms: No Python IntelliSense, code completion, or type checking

Solution:

1. Open VS Code Command Palette (Ctrl+Shift+P or Cmd+Shift+P)
2. Run "Python: Select Interpreter"
3. Choose the correct Python interpreter (virtual environment if using one)
4. Reload VS Code window

Problem: VS Code not detecting virtual environment

Symptoms: Wrong Python interpreter selected

Solution:

1. Ensure you've activated the virtual environment in the terminal
2. Open Command Palette and run "Python: Select Interpreter"
3. Select the interpreter from .venv folder
4. Check the status bar (bottom left) shows the correct Python version

PlatformIO (Wio Terminal)

Problem: PlatformIO installation fails

Error: Various errors during PlatformIO installation

Solution:

1. Ensure VS Code is up to date
2. Install the C/C++ extension first
3. Restart VS Code after installing PlatformIO
4. Check your internet connection (PlatformIO downloads large files)

Problem: Board not detected by PlatformIO

Symptoms: Cannot upload code to Wio Terminal

Solution:

1. Try a different USB cable (some cables are charge-only)
2. Check Device Manager (Windows) or ls /dev/tty* (macOS/Linux)
3. Install or update USB drivers
4. Try a different USB port
5. Slide the power switch on the Wio Terminal twice quickly to enter bootloader mode

Problem: Compilation errors in PlatformIO

Error: fatal error: Arduino.h: No such file or directory

Solution:

1. Delete .pio folder in your project
2. Run "PlatformIO: Rebuild" from Command Palette
3. Ensure platformio.ini has correct board configuration:

   [env:seeed_wio_terminal]
   platform = atmelsam
   board = seeed_wio_terminal
   framework = arduino
   

Grove Libraries

Problem: Grove library import fails on Raspberry Pi

Error: ModuleNotFoundError: No module named 'grove'

Solution:

1. Reinstall Grove libraries:

   cd ~
   git clone https://github.com/Seeed-Studio/grove.py
   cd grove.py
   sudo pip3 install .
   

2. If using virtual environment, you may need to install globally or copy libraries
3. Verify I2C is enabled: sudo raspi-config nonint do_i2c 0

Problem: Grove sensor not detected

Error: IOError: [Errno 121] Remote I/O error

Solution:

1. Check physical connections (ensure Grove cable is fully inserted)
2. Verify sensor is connected to correct port (analog, digital, I2C, UART)
3. Run i2cdetect -y 1 to see if device appears on I2C bus
4. Try a different Grove cable
5. Ensure Grove Base Hat is properly seated on Raspberry Pi GPIO pins

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Hardware Issues

Raspberry Pi

Problem: Raspberry Pi won't boot

Symptoms: No display, no LED activity, or rainbow screen

Solution:

1. Check power supply: Use official 5V 3A USB-C power supply for Pi 4
2. SD card issues:
   • Reformat SD card and reinstall Raspberry Pi OS
   • Try a different SD card (use recommended brands)
   • Ensure SD card is properly inserted
3. Check HDMI connection: Try both HDMI ports on Pi 4, use HDMI port closest to power

Problem: Cannot SSH to Raspberry Pi

Symptoms: Connection refused or timeout

Solution:

1. Enable SSH:
   • When flashing SD card with Raspberry Pi Imager, configure SSH in advanced options
   • Or create empty file named ssh (no extension) in boot partition
2. Find Pi's IP address:
   • Check your router's connected devices
   • Use ping raspberrypi.local (if mDNS works)
   • Use network scanning tools like nmap or Angry IP Scanner
3. Check network:
   • Ensure Pi is on same network as your computer
   • Try ethernet connection instead of WiFi
4. Verify username/password (default: username pi, password raspberry)

Problem: Grove Base Hat not recognized

Symptoms: Sensors not working, I2C errors

Solution:

1. Ensure Base Hat is properly seated on all GPIO pins
2. Check for bent pins on Pi or Base Hat
3. Enable I2C interface:

   sudo raspi-config nonint do_i2c 0
   sudo reboot
   

4. Verify I2C is working: i2cdetect -y 1

Problem: Raspberry Pi running slow

Symptoms: Laggy UI, slow response

Solution:

1. Check SD card speed (use Class 10 or better, or SSD via USB)
2. Free up disk space: df -h to check, delete unnecessary files
3. Reduce GPU memory in raspi-config if not using camera/display heavily
4. Close unnecessary applications
5. Consider upgrading to Pi 4 with more RAM if using Pi 3 or older

Wio Terminal

Problem: Wio Terminal screen stays blank

Symptoms: No display output after uploading code

Solution:

1. Check if code initializes the display (TFT_eSPI library)
2. Update Wio Terminal firmware from Seeed Wiki
3. Add display initialization code:

   #include <TFT_eSPI.h>
   TFT_eSPI tft;
   tft.begin();
   tft.fillScreen(TFT_BLACK);
   

4. Try uploading example sketch from PlatformIO to test hardware

Problem: WiFi not working on Wio Terminal

Symptoms: Cannot connect to WiFi, network errors

Solution:

1. Update WiFi firmware: Follow Wio Terminal WiFi firmware update guide
2. Check WiFi credentials: Ensure SSID and password are correct
3. WiFi band: Wio Terminal only supports 2.4GHz WiFi (not 5GHz)
4. Signal strength: Move closer to router
5. Router settings: Some enterprise/WPA-Enterprise networks may not work

Problem: Wio Terminal not recognized by computer

Symptoms: USB device not detected

Solution:

1. Try different USB cable: Use data cable, not charge-only cable
2. Enter bootloader mode: Slide power switch down twice quickly
   • Blue LED should pulse, device appears as "Arduino" in Device Manager
3. Install drivers (Windows):
   • Download and install Seeed USB driver
4. Try different USB port: Avoid USB hubs, use direct connection
5. Update system USB drivers

Problem: Sensors not working on Wio Terminal

Symptoms: Grove sensors not reading data

Solution:

1. Check Grove cable connections
2. Verify you're using correct Grove port (left or right)
3. Include correct libraries for sensor
4. Check sensor power requirements
5. Test sensor with example code from library

Virtual Device (CounterFit)

Problem: CounterFit app won't start

Error: Various Python errors when starting CounterFit

Solution:

1. Ensure virtual environment is activated
2. Install/reinstall CounterFit:

   pip install CounterFit
   

3. Check port 5000 is not already in use:
   • Windows: netstat -ano | findstr :5000
   • macOS/Linux: lsof -i :5000
4. Kill process using port 5000 or use different port:

   counterfit --port 5001
   

Problem: Cannot connect to CounterFit from code

Error: Connection refused or timeout

Solution:

1. Verify CounterFit is running: Open browser to http://127.0.0.1:5000
2. Check connection URL in code matches CounterFit address
3. Ensure firewall isn't blocking connection
4. Try restarting both CounterFit app and your code

Problem: Sensors not appearing in CounterFit

Symptoms: Created sensors don't show in CounterFit UI

Solution:

1. Create sensors in CounterFit UI before running code
2. Refresh browser page
3. Check sensor type matches what code expects
4. Clear browser cache

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Connectivity Issues

WiFi Connection

Problem: Device can't connect to WiFi

Symptoms: Connection timeout, authentication failed

Solution:

1. Check SSID and password: Verify credentials are correct
2. WiFi band: Most IoT devices only support 2.4GHz (not 5GHz)
3. Router settings:
   • Disable AP isolation if enabled
   • Use WPA2-PSK security (avoid WPA3, WEP, or open networks)
   • Ensure DHCP is enabled
4. Hidden networks: If SSID is hidden, you may need to explicitly configure it
5. Signal strength: Move device closer to router
6. Interference: Other devices, microwaves, or walls can interfere

Problem: WiFi connection drops frequently

Symptoms: Intermittent connectivity

Solution:

1. Check router stability and consider reboot
2. Update device firmware
3. Use static IP instead of DHCP
4. Reduce distance to router or add WiFi extender
5. Check for interference from other devices
6. Verify power supply is adequate (especially for Raspberry Pi)

Cloud Services

Problem: Cannot connect to Azure IoT Hub

Error: Authentication failed, connection refused

Solution:

1. Verify credentials:
   • Check connection string is correct
   • Ensure no extra spaces or line breaks in connection string
2. Check device registration: Device must be registered in IoT Hub
3. Firewall/proxy: Ensure outbound MQTT (port 8883) or HTTPS (port 443) is allowed
4. IoT Hub region: Ensure IoT Hub is running and not in different region causing latency
5. Quota limits: Check if free tier limits are exceeded
6. Test connection:

   az iot hub device-identity show-connection-string --hub-name YourIoTHub --device-id YourDevice
   

Problem: Azure Functions not triggering

Symptoms: Messages sent but function doesn't execute

Solution:

1. Check Function App is running (not stopped)
2. Verify connection string in Function App settings
3. Check function logs in Azure Portal
4. Ensure Event Hub compatible endpoint is configured correctly
5. Verify message format matches function expectations
6. Check Function App service plan (consumption vs. dedicated)

MQTT

Problem: MQTT connection fails

Error: Connection refused, authentication failed

Solution:

1. Broker address: Verify broker URL/IP is correct
2. Port: Check port number (1883 for unencrypted, 8883 for TLS)
3. Authentication: Verify username/password if required
4. TLS/SSL: Ensure certificates are valid and trusted
5. Firewall: Check port is not blocked
6. Test with MQTT client: Use MQTT Explorer or mosquitto_pub/sub to test

Problem: MQTT messages not received

Symptoms: Messages published but not received by subscribers

Solution:

1. Topic names: Verify subscriber topic matches publisher topic exactly
2. QoS level: Try QoS 1 or 2 instead of 0
3. Wildcards: Check topic wildcards are used correctly (+ for single level, # for multi-level)
4. Retained messages: Publisher can set retain flag to keep last message
5. Connection timing: Ensure subscriber connects before messages are published

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Sensor and Actuator Issues

Grove Sensors

Problem: Sensor returns incorrect values

Symptoms: Readings are 0, -1, or nonsensical values

Solution:

1. Check connections: Ensure sensor is properly connected
2. Correct port: Verify sensor is in correct port type:
   • Analog sensors → Analog ports (A0, A2, A4)
   • Digital sensors → Digital ports (D5, D16, D18, etc.)
   • I2C sensors → I2C ports
3. Calibration: Some sensors need calibration (soil moisture, light)
4. Power cycle: Disconnect and reconnect sensor
5. Sensor datasheet: Check sensor specifications and requirements

Problem: Capacitive soil moisture sensor always reads wet

Symptoms: Sensor reads high moisture even when dry

Solution:

1. Calibration needed: Soil sensors require calibration:
   • Read value in air (dry baseline)
   • Read value in water (wet baseline)
   • Map readings between these values
2. Check sensor coating: Moisture sensors can degrade if coating damaged
3. Placement: Ensure sensor is fully inserted in soil

Problem: Temperature/humidity sensor readings incorrect

Symptoms: DHT11/DHT22 shows wrong temperature or humidity

Solution:

1. Sensor placement: Avoid direct sunlight, heat sources, or airflow
2. Warm-up time: Allow sensor 2 seconds after power-on before reading
3. Read frequency: DHT sensors need time between reads (at least 2 seconds)
4. Check for condensation: Can affect readings
5. Sensor quality: DHT11 is less accurate than DHT22

Camera

Problem: Camera not detected on Raspberry Pi

Error: mmal: mmal_vc_component_create: failed to create component 'vc.ril.camera'

Solution:

1. Enable camera interface:

   sudo raspi-config
   

   Go to Interface Options → Camera → Enable
2. Check ribbon cable: Ensure camera cable is properly inserted
   • Blue side faces USB ports on Pi Zero
   • Blue side faces away from USB ports on Pi 4
3. Update firmware:

   sudo apt update
   sudo apt full-upgrade
   sudo reboot
   

4. Test camera:

   raspistill -o test.jpg
   

Problem: Camera images are poor quality

Symptoms: Blurry, dark, or washed out images

Solution:

1. Focus: Remove protective film from lens, adjust focus if adjustable
2. Lighting: Ensure adequate lighting
3. Camera settings: Adjust exposure, ISO, white balance in code
4. Stability: Keep camera steady, use tripod if needed
5. Resolution: Don't exceed camera's maximum resolution

Microphone and Speaker

Problem: No audio input/output

Symptoms: Microphone not recording, speaker not playing

Solution:

1. Check connections: Verify audio devices are properly connected
2. Test hardware:
   • Speaker: speaker-test -t wav -c 2
   • Microphone: arecord -l to list, arecord test.wav to record
3. Volume settings: Check and adjust volume:

   alsamixer
   

4. Select audio device: Specify correct audio device in code
5. Driver issues: Update ALSA or reinstall audio drivers

Problem: ReSpeaker hat not working

Symptoms: Audio device not detected

Solution:

1. Install drivers:

   git clone https://github.com/HinTak/seeed-voicecard
   cd seeed-voicecard
   sudo ./install.sh
   sudo reboot
   

2. Check installation: arecord -l should list ReSpeaker
3. Update firmware: Some Pi OS versions need driver updates
4. Check seating: Ensure hat is properly connected to GPIO pins

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Development Environment Issues

VS Code

Problem: Terminal not activating virtual environment automatically

Symptoms: Terminal opens but venv not activated

Solution:

1. Set Python interpreter: Command Palette → "Python: Select Interpreter" → Choose venv
2. Restart VS Code after selecting interpreter
3. Check settings: In settings.json, add:

   "python.terminal.activateEnvironment": true
   

Problem: Code not running on device

Symptoms: Code runs but nothing happens on device

Solution:

1. Verify code is saved (check dot on file tab)
2. Check which Python is running: which python or where python
3. For Wio Terminal: Ensure code is uploaded via PlatformIO (click upload button)
4. For Raspberry Pi: SSH into Pi and run code there
5. Check output window for errors

Problem: IntelliSense not showing library functions

Symptoms: No autocomplete for imported modules

Solution:

1. Ensure library is installed in current environment
2. Reload VS Code window
3. Check Python interpreter is correct
4. Install type stubs if available: pip install types-<library-name>

Python Virtual Environments

Problem: Cannot create virtual environment

Error: The virtual environment was not created successfully

Solution:

1. Install venv module:
   • Ubuntu/Debian: sudo apt install python3-venv
   • macOS: Should be included with Python
   • Windows: Reinstall Python with all components
2. Check Python installation: Verify Python is properly installed
3. Use full path: Try python3 -m venv .venv with explicit python3 call

Problem: Packages installed in wrong location

Symptoms: Import error after installing package

Solution:

1. Verify venv is activated: Command prompt should show (.venv)
2. Check pip location: which pip should point to .venv/bin/pip
3. Reinstall in venv: Activate venv, then pip install <package>
4. Don't use sudo with pip in virtual environment

Problem: Virtual environment not portable

Symptoms: Venv doesn't work after moving or on different computer

Solution:

1. Don't move venvs: Delete and recreate in new location
2. Use requirements.txt:

   pip freeze > requirements.txt
   pip install -r requirements.txt
   

3. Recreate venv:

   python3 -m venv .venv
   source .venv/bin/activate  # or activate.bat on Windows
   pip install -r requirements.txt
   

Dependencies

Problem: Package installation fails

Error: Various pip errors during installation

Solution:

1. Update pip:

   pip install --upgrade pip
   

2. Install build tools:
   • Ubuntu/Debian: sudo apt install build-essential python3-dev
   • macOS: xcode-select --install
   • Windows: Install Visual Studio Build Tools
3. Check internet connection
4. Try different package index: pip install --index-url https://pypi.org/simple/ <package>
5. Install specific version: pip install <package>==<version>

Problem: Dependency conflicts

Error: ERROR: pip's dependency resolver does not currently take into account all the packages that are installed

Solution:

1. Use fresh virtual environment for each project
2. Update packages: pip install --upgrade <package>
3. Check requirements: Use pip check to find conflicts
4. Install compatible versions: Specify version ranges in requirements.txt

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Performance Issues

Problem: Code runs slowly

Symptoms: Delays, timeouts, unresponsive behavior

Solution:

1. Reduce sensor read frequency: Don't read sensors too often
2. Optimize loops: Avoid busy-waiting, use sleep() or delays
3. Memory issues:
   • Close unnecessary applications
   • Free up storage space
   • Monitor with top or htop on Pi
4. SD card speed: Use faster SD card or SSD for Raspberry Pi
5. Network delays: Use async operations for network calls

Problem: Out of memory errors

Error: MemoryError or system freezing

Solution:

1. For Raspberry Pi:
   • Close unnecessary applications
   • Increase swap space
   • Use lighter OS (Lite version)
   • Upgrade RAM (Pi 4 has 2/4/8GB options)
2. For Wio Terminal:
   • Reduce buffer sizes
   • Use smaller images
   • Optimize string usage
   • Check for memory leaks (unreleased memory)

Problem: Data loss or corruption

Symptoms: Missing messages, corrupted files

Solution:

1. SD card issues:
   • Use quality SD cards (avoid cheap/counterfeit)
   • Regular backups
   • Clean shutdown (don't pull power)
2. Buffer overflow: Increase buffer sizes in code
3. Network reliability: Implement retry logic and error handling
4. Quality of Service: Use MQTT QoS 1 or 2 for important messages

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Common Error Messages

ModuleNotFoundError: No module named 'X'

Cause: Package not installed or virtual environment not activated

Solution:

pip install X

Ensure virtual environment is activated first.

Permission denied on Linux/macOS

Cause: Need elevated permissions or file permissions issue

Solution:

• For system operations: Use sudo
• For pip: DON'T use sudo with venv, activate venv first
• For serial port: Add user to dialout group: sudo usermod -a -G dialout $USER, then logout/login

OSError: [Errno 98] Address already in use

Cause: Port is already being used by another process

Solution:

1. Find process using port: lsof -i :<port> or netstat -ano | findstr :<port>
2. Kill process or use different port in your code

SSL: CERTIFICATE_VERIFY_FAILED

Cause: SSL certificate validation failing

Solution:

1. Update certificates: pip install --upgrade certifi
2. Check system time is correct: date
3. For development only (not production): Disable verification in code

IndentationError: unexpected indent

Cause: Python indentation issues (mixing tabs/spaces)

Solution:

1. Use consistent indentation (4 spaces is Python standard)
2. Configure editor to use spaces instead of tabs
3. VS Code: Set "editor.insertSpaces": true and "editor.tabSize": 4

UnicodeDecodeError or UnicodeEncodeError

Cause: Character encoding issues

Solution:

# When reading files
with open('file.txt', 'r', encoding='utf-8') as f:
    content = f.read()

# When writing files
with open('file.txt', 'w', encoding='utf-8') as f:
    f.write(content)

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Getting Help

If you've tried these troubleshooting steps and still have issues:

1. Check Existing Resources

• Documentation: Review the README and lesson instructions
• Hardware guides: Check hardware.md for hardware-specific info
• Seeed Studio Wiki: Seeed Studio Wiki for Grove components

2. Search for Similar Issues

• GitHub Issues: Search existing issues
• Stack Overflow: Search for error messages
• Device forums: Check Raspberry Pi forums or Arduino forums

3. Create a GitHub Issue

If you can't find a solution:

1. Go to GitHub Issues
2. Click "New Issue"
3. Provide:
   • Clear description of the problem
   • Steps to reproduce
   • Error messages (full text)
   • Hardware/software versions
   • What you've already tried
   • Screenshots if relevant

4. Join the Community

• Discord: Microsoft Foundry Discord
• Microsoft Learn: Microsoft Learn IoT

5. Provide Good Bug Reports

A good bug report includes:

• Environment: OS, Python version, hardware used
• Steps to reproduce: Exact steps that cause the issue
• Expected behavior: What should happen
• Actual behavior: What actually happens
• Error messages: Complete error text, not screenshots
• Code: Minimal code example that reproduces the issue

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Tips for Prevention

General Best Practices

1. Keep backups: Regular backups of working SD cards/code
2. Document changes: Note what works in comments
3. Version control: Use git to track code changes
4. Test incrementally: Test small changes before combining
5. Read error messages: They often tell you exactly what's wrong
6. Update regularly: Keep software/firmware up to date
7. Use quality components: Avoid cheap cables/power supplies
8. Stable power: Use appropriate power supply (especially Pi)

Development Workflow

1. Start simple: Begin with example code that works
2. One change at a time: Easier to find what breaks
3. Test frequently: Catch issues early
4. Keep it clean: Organize files and code logically
5. Comment code: Future you will appreciate it

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This troubleshooting guide is maintained by the community. If you find a solution to a problem not listed here, please consider contributing to help others!