Example 6: Button Control

Experiment Overview

Read button state via GPIO digital input (pull-up), triggering LED, buzzer and other peripheral actions. The Puzhong development board has 4 buttons (KEY1-KEY4), which read LOW when pressed.

Hardware Wiring

Board Label	GPIO Pin	Connected Device
KEY1	GPIO14	Button (LOW when pressed)
KEY2	GPIO27	Button (LOW when pressed)
KEY3	GPIO26	Button (LOW when pressed)
KEY4	GPIO25	Button (LOW when pressed)

One side of the button connects to GPIO, the other to GND, using internal pull-up resistors, GPIO reads LOW when pressed.

JSON Configuration Example

{
  "peripherals": [
    {
      "id": "key1",
      "name": "Button 1",
      "type": 13,
      "enabled": false,
      "pins": [14],
      "params": {}
    },
    {
      "id": "key2",
      "name": "Button 2",
      "type": 13,
      "enabled": false,
      "pins": [27],
      "params": {}
    },
    {
      "id": "key3",
      "name": "Button 3",
      "type": 13,
      "enabled": false,
      "pins": [26],
      "params": {}
    },
    {
      "id": "key4",
      "name": "Button 4",
      "type": 13,
      "enabled": false,
      "pins": [25],
      "params": {}
    }
  ]
}

Peripheral Execution Linkage

Scenario 1: Button Controls LED (Poll Trigger)

Function: Press Button 1 to toggle LED-D1 on/off state

Web Interface Configuration Steps

Step 1: Create Rule

1. Click left menu Peripheral Configuration → Switch to Peripheral Execution Management tab
2. Click New Rule button
3. Fill in basic configuration:
   • Rule Name: Button Control LED
   • Report Data: ❌ Disable
   • Enabled: ✅ Enable

Step 2: Configure Trigger

1. Click Add Trigger button

2. Fill in trigger configuration:

   Field	Value	Description
   Trigger Type	Select Poll Trigger	Periodically detect button state
   Target Peripheral	Select key1	Button peripheral to poll
   Poll Interval	50 ms	Detection frequency, 50ms avoids missed presses
   Response Timeout	1000 ms	Default is fine
   Retry Count	2	Default is fine
   Poll Delay	100 ms	Default is fine
   Comparison Operator	Select Equals	Exact match
   Comparison Value	0	LOW level (0) when pressed

Step 3: Configure Action

1. Click Add Action button

2. Fill in action configuration:

   Field	Value	Description
   Action Type	Select Toggle Level	Flip GPIO state
   Target Peripheral	Select led_d1	LED to control

3. Click Save button

Execution Flow:

Detect every 50ms
  ↓
Read key1 state
  ↓
Check: key1 == 0 ? (pressed)
  ↓ Yes
Toggle led_d1 state (on→off or off→on)

⚠️ Note: Poll interval recommended at 50ms, too fast wastes CPU, too slow may miss short presses

---

Scenario 2: Button Interrupt Control (Event Trigger)

Function: Use interrupt mode for faster response

Prerequisites

Need to configure button as interrupt type first:

1. Edit key1 peripheral
2. Change Peripheral Type to Interrupt (Falling Edge) (type: 19)
3. After saving, system auto-generates event: button_key1.pressed

Web Interface Configuration Steps

Step 1: Create Rule

1. Click New Rule
2. Fill in basic configuration:
   • Rule Name: Button Interrupt Control
   • Report Data: ✅ Enable
   • Enabled: ✅ Enable

Step 2: Configure Trigger

1. Click Add Trigger button

2. Fill in trigger configuration:

   Field	Value	Description
   Trigger Type	Select Event Trigger	Respond to system events
   Event Category	Select Button Event	Select from dropdown
   Specific Event	Select button_key1.pressed	Button 1 press event

Step 3: Configure Action

1. Click Add Action button

2. Fill in action configuration:

   Field	Value	Description
   Action Type	Select HIGH Level	GPIO output HIGH
   Target Peripheral	Select relay_01	Control relay

3. Click Save button

Execution Flow:

Button pressed (falling edge)
  ↓
Trigger interrupt event
  ↓
Emit button_key1.pressed event
  ↓
Match event trigger
  ↓
Execute action: relay energizes

💡 Advantage: Interrupt mode response speed <1ms, much faster than polling's 50ms

{
  "name": "Button Control LED",
  "enabled": true,
  "triggers": [
    {
      "type": "poll",
      "params": {
        "peripheralId": "key1",
        "interval": 50,
        "condition": "value == 0"
      }
    }
  ],
  "actions": [
    { "type": "gpio_toggle", "params": { "peripheralId": "led_d1" } }
  ]
}

Using Interrupt Mode (More Precise)

{
  "name": "Button Interrupt Control",
  "enabled": true,
  "triggers": [
    {
      "type": "event",
      "params": {
        "eventType": 100,
        "source": "key1"
      }
    }
  ],
  "actions": [
    { "type": "gpio_write", "params": { "peripheralId": "relay_01", "value": 1 } }
  ]
}

Notes

1. Debouncing: FastBee internally applies 50ms software debouncing to GPIO input
2. Pull-up/Pull-down: Buttons to GND use pull-up (type: 13), buttons to VCC use pull-down (type: 14)
3. Poll Interval: 50ms interval recommended for button detection, balancing response speed and resource usage
4. GPIO25 Conflict: If using both relay and Button 4, pins need to be changed
5. Long Press Detection: Can distinguish long/short press by recording press duration in scripts