Skip to content

Activity Timer

Visual countdown timer for classroom activities with configurable preset profiles and RGB LED feedback.

Overview

The Activity Timer helps manage classroom time with visual countdown displays and LED indicators. Perfect for activity transitions, breaks, and timed exercises.

URL: /plugins/edupi/activity_timer/

Hardware Requirements

  • RGB LED (common cathode)
  • 3x 220Ω resistors
  • Optional: Buzzer module
  • Breadboard and jumper wires

GPIO Pin Connections

Component GPIO Pin Physical Pin Color
LED Red 17 11 Red wire
LED Green 27 13 Green wire
LED Blue 22 15 Blue wire
Buzzer (optional) 24 18 Any wire

Preset Profiles

Four built-in presets for common classroom scenarios:

Minute of Silence

  • Duration: 60 seconds
  • Display Color: Indigo (calming)
  • LED Colors: Blue tones
  • Use Case: Calming students before activities

Break Time

  • Duration: 10 minutes
  • Display Color: Green
  • LED Colors: Green to yellow to red
  • Use Case: Standard break periods

Activity

  • Duration: 30 minutes
  • Display Color: Amber
  • LED Colors: Amber to orange to red
  • Use Case: Regular class activities

Custom

  • Duration: User-defined (1-120 minutes)
  • Display Color: User-selected
  • LED Colors: Configurable
  • Use Case: Any custom timing need

Interface Controls

Main Timer Display

Large digital countdown showing: - Remaining Time: Minutes and seconds - Status: Running, Paused, or Stopped - Progress: Visual indicator

Preset Buttons

Click any preset to load its configuration:

  1. Minute of Silence - Blue button
  2. Break Time - Green button
  3. Activity - Amber button
  4. Custom - Opens duration selector

Playback Controls

Button Action Keyboard Shortcut
Start Begin countdown Space
Pause Pause timer Space
Resume Continue countdown Space
Stop End timer, reset to 0 Escape

LED Visual Feedback

The RGB LED shows remaining time visually:

Time Remaining LED Color Meaning
> 50% Green Plenty of time
20-50% Yellow Time passing
< 20% Red Time running out
Finished Flashing Red Time's up!

LED Brightness

Adjust LED brightness in Settings to match your classroom lighting.

Custom Timer

Create timers with custom durations:

  1. Click Custom preset button
  2. Enter duration (1-120 minutes)
  3. Select display color
  4. Click Start

Configuration Options

Access settings at /plugins/edupi/activity_timer/config/ or via the main Settings page:

  • Default Duration: Default timer length (1-120 min)
  • LED Brightness: LED intensity percentage (10-100%)
  • Warning Threshold: When LED changes color (5-50% remaining)
  • Enable Buzzer: Play sound when timer completes

Session Tracking

Each timer session is recorded in the database:

  • Start time
  • Duration
  • Preset used
  • Completion status

View history in the plugin interface.

Use Cases

Transition Management

Set a 2-minute timer for cleanup: 1. Select Custom preset 2. Set duration to 2 minutes 3. Choose calming blue color 4. Click Start

Students see the LED change from green → yellow → red, helping them manage time.

Focus Sessions

Use Minute of Silence before writing activities: - Calming blue display - 60-second countdown - Students prepare mentally while watching the timer

Activity Timing

Standard 30-minute activity: 1. Select Activity preset 2. Click Start 3. LED shows progress throughout 4. Optional buzzer alerts at end

Best Practices

LED Brightness

  • Classroom with natural light: 80-100%
  • Dim classroom: 50-70%
  • Dark room: 30-50%

Warning Threshold

  • Younger students: 30% (earlier warning)
  • Older students: 20% (standard)
  • Urgent activities: 10% (minimal warning)

Combining with Other Plugins

The Activity Timer runs independently:

  1. Start Activity Timer
  2. Navigate to Noise Monitor
  3. Check classroom noise while timer runs
  4. Return to see remaining time

See Background Activities for details.

Troubleshooting

LED Not Lighting

  1. Check wiring connections
  2. Verify GPIO pins in plugin settings
  3. Check LED brightness setting (> 0%)
  4. Ensure LED is common cathode

Buzzer Not Working

  1. Verify buzzer polarity (+/-)
  2. Check buzzer enabled in settings
  3. Test with multimeter

Timer Not Starting

  1. Check browser console for JavaScript errors
  2. Verify WebSocket connection (if applicable)
  3. Refresh page and try again

Wrong Colors

  • Check RGB LED wiring matches pin assignments
  • Common cathode LEDs have different wiring than common anode

Technical Details

  • Updates every second during countdown
  • Uses threading for background operation
  • Stores session data in SQLite database
  • HTTP polling for web interface updates
  • WebSocket support planned for future versions