node-red-contrib-pulse-edge

A Node-RED node for edge detection - outputs a pulse when a rising or falling edge is detected.

Features

• Detects rising edge (false→true / 0→1)
• Detects falling edge (true→false / 1→0)
• Mode: Rising, Falling, or Both
• Accepts boolean or 0/1 number input
• Configurable initial state
• Single pulse output (no timers needed)

How It Works

Signal:    LOW ──────┐         ┌────── HIGH
                     │         │
                     └─────────┘

Rising:              ↑ PULSE
Falling:                       ↑ PULSE
Both:                ↑ PULSE   ↑ PULSE

Configuration

| Property | Description | Options | |----------|-------------|---------| | Mode | Which edge to detect | Rising / Falling / Both | | Initial State | Assumed state before first input | undefined / true / false |

Usage

Input

• msg.payload - Boolean (true/false) or Number (1/0)

Output (only on detected edge)

• msg.payload - Always true
• msg.edge - "rising" or "falling"
• msg.previousState - State before the edge

Example Output

{
  "payload": true,
  "edge": "rising",
  "previousState": false
}

Examples

Rising Edge Mode

Input: false → (sets state, no output)
Input: true  → OUTPUT {edge: "rising"}
Input: true  → (no change, no output)
Input: false → (falling ignored)
Input: true  → OUTPUT {edge: "rising"}

Both Edges Mode

Input: 0 → (sets state, no output)
Input: 1 → OUTPUT {edge: "rising"}
Input: 0 → OUTPUT {edge: "falling"}
Input: 1 → OUTPUT {edge: "rising"}

Use Cases

• Button Press: Detect button down (rising) or release (falling)
• Sensor Trigger: Single action when motion detected
• Counter: Count each state change
• Signal Monitoring: Verify signal is still changing (with watchdog)

Node Status

Shows current state and configured mode:

• HIGH | ↑ - State is true, rising mode
• LOW | ↓ - State is false, falling mode
• HIGH | ↑↓ - State is true, both edges mode

Author

sr.rpo

License

MIT