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On Button Input Released

This block is triggered when a button or digital input is released (goes HIGH to LOW or LOW to HIGH, depending on configuration).

On Button Input Released Block

Overview​

The On Button Input Released block detects button release events on GPIO digital input pins, enabling detection of button hold duration and release-triggered actions.

Configuration​

  • GPIO Line: Which digital input pin to monitor
  • Trigger Edge: Rising edge or falling edge (opposite of press)
  • Debounce: Debounce time in milliseconds

Use Cases​

Common button release scenarios:

Momentary Actions​

Execute action only after button released:

On Button Pressed:
    Show "Action pending..."
On Button Released:
    Execute action
    Show "Action complete"

Hold Duration​

Measure how long button was held:

On Button Pressed:
    Start timer
    
On Button Released:
    Stop timer
    duration = timer value
    
    If duration < 1 second:
        Short press action
    Else if duration < 5 seconds:
        Medium press action
    Else:
        Long press action

Safety Confirmation​

Require button release before proceeding:

On Button Pressed:
    Prepare action
    
On Button Released:
    Confirm ready
    Execute when safe

Toggle with Feedback​

Provide feedback during press, execute on release:

On Button Pressed:
    Blink LED
    
On Button Released:
    state = NOT state
    Set output to state
    Stop blinking

Press-Release Pattern​

Typical button handling pattern:

PRESSED:
1. Button goes active
2. On Button Pressed triggers
3. Start action or timer
4. Provide feedback

HELD:
5. Button remains active
6. Optional: Monitor hold duration
7. Optional: Execute hold action

RELEASED:
8. Button goes inactive
9. On Button Released triggers
10. Complete action
11. Update state

Applications​

Elevator Button​

On Button Pressed:
    Illuminate button LED
    Queue floor request
    
On Button Released:
    (Button stays lit until floor reached)

Push-to-Talk​

On Button Pressed:
    Enable microphone
    Start recording
    
On Button Released:
    Disable microphone
    Stop recording
    Send audio

Manual Control​

On Button Pressed:
    Motor starts
    
On Button Released:
    Motor stops

Copy/Paste Function​

On Button Pressed (short):
    Copy value
    
On Button Pressed (long):
    Paste value
    
(Determined on release)

Hold Duration Detection​

Implement press duration detection:

Variables: press_time, release_time, duration

On Button Pressed:
    press_time = current_time
    
On Button Released:
    release_time = current_time
    duration = release_time - press_time
    
    If duration < 500ms:
        Quick tap action
    Else if duration < 2000ms:
        Normal press action
    Else if duration < 5000ms:
        Long press action
    Else:
        Extra long press action

Debouncing​

Release debouncing same as press:

  • Prevents false releases
  • Filters contact bounce
  • Typical: 10-50ms
  • Adjust based on button type

State Management​

Track button state:

Variable: button_held = false

On Button Pressed:
    button_held = true
    
On Button Released:
    button_held = false

User Feedback​

Provide feedback on release:

On Button Released:
    Beep confirmation
    Flash LED
    Update display
    Log action

Safety Applications​

Safety-critical release handling:

On Emergency Stop Pressed:
    Immediate shutdown
    Lock out controls
    
On Emergency Stop Released:
    Remain in safe state
    Require manual reset
    Log reset event

Multi-Button Sequences​

Implement button sequences:

On Button1 Pressed then Released:
    sequence_step = 1
    
On Button2 Pressed then Released:
    If sequence_step == 1:
        sequence_step = 2
        
On Button3 Pressed then Released:
    If sequence_step == 2:
        Execute secret function
        sequence_step = 0

Hardware Considerations​

Pull Resistors​

Same configuration as button press:

  • Pull-up or pull-down
  • Match press configuration
  • Consistent logic levels

Noise Filtering​

Release detection benefits from:

  • Hardware debounce (RC filter)
  • Software debounce
  • Schmitt trigger inputs

Performance​

Release detection:

  • Same speed as press detection
  • Negligible CPU overhead
  • Interrupt-driven (efficient)
  • Real-time response

Troubleshooting​

Common release issues:

  • Multiple triggers: Increase debounce time
  • Release not detected: Check wiring and pull resistors
  • Delayed response: Verify debounce time not too long
  • Inconsistent: Check for loose connections

Best Practices​

Button release best practices:

  1. Always pair with press handler
  2. Use appropriate debounce
  3. Validate state before action
  4. Provide user feedback
  5. Handle held vs released logic
  6. Test edge cases
  7. Consider accessibility

Advanced Patterns​

Click and Drag​

On Button Pressed:
    Start drag operation
    Track position
    
On Button Released:
    Complete drag
    Commit position

Gesture Detection​

On Button1 Pressed:
    timestamp1 = current_time
    
On Button1 Released:
    duration1 = current_time - timestamp1
    
On Button2 Pressed:
    timestamp2 = current_time
    gap = timestamp2 - release_time1
    
(Analyze timing for gesture)

Linking to Variables​

Release events can:

  • Update button state variables
  • Store duration in variables
  • Trigger variable changes
  • Log release events

See Also​