---
title: "LED Feedback Component Documentation"
description: "Documentation for the LED Feedback component providing visual status indicators using addressable LED strips"
keywords: "LED Feedback, NeoPixel, WS2812B, SK6812, ESP32, visual indicator"
---

## LED Feedback

**Path**: [`src/LEDFeedback.cpp`](../src/LEDFeedback.cpp)

**Revision History**: Initial documentation

The LED Feedback component provides visual status indication through addressable LED strips (NeoPixel compatible). It offers multiple display modes including fading effects, level indicators, and tri-color blinking patterns that can be controlled via Modbus.

## REQUIREMENTS

- Digital output pin connected to WS2812B/SK6812 compatible LED strip
- 5V power supply for the LED strip (separate from microcontroller logic)
- Modbus TCP connection for remote control

## FEATURES

- Multiple display modes:
  - OFF: All LEDs turned off
  - FADE_R_B: Smooth color transition between red and blue
  - RANGE: Level indicator (0-100%) using lit LEDs
  - TRI_COLOR_BLINK: Three-section traffic light style blinking (red, yellow, green)
- Modbus control interface for mode selection and parameters
- Adjustable update rate for animations
- Configurable pixel count to support different strip lengths

## DEPENDENCIES

- [Adafruit_NeoPixel](https://github.com/adafruit/Adafruit_NeoPixel) - Library for controlling addressable LED strips
- [ArduinoLog](https://github.com/thijse/Arduino-Log) - Logging functionality
- [ModbusTCP](../src/modbus/ModbusTCP.h) - For Modbus communication

```mermaid
graph TD
    LEDFeedback --> Component
    LEDFeedback --> Adafruit_NeoPixel
    LEDFeedback --> ModbusTCP
    LEDFeedback --> ArduinoLog
    LEDFeedback --> Bridge
```

## BEHAVIOUR

```mermaid
stateDiagram-v2
    [*] --> OFF
    OFF --> FADE_R_B: Modbus write mode=1
    OFF --> RANGE: Modbus write mode=2
    OFF --> TRI_COLOR_BLINK: Modbus write mode=3
    
    FADE_R_B --> OFF: Modbus write mode=0
    FADE_R_B --> RANGE: Modbus write mode=2
    FADE_R_B --> TRI_COLOR_BLINK: Modbus write mode=3
    
    RANGE --> OFF: Modbus write mode=0
    RANGE --> FADE_R_B: Modbus write mode=1
    RANGE --> TRI_COLOR_BLINK: Modbus write mode=3
    RANGE: Update level via Modbus
    
    TRI_COLOR_BLINK --> OFF: Modbus write mode=0
    TRI_COLOR_BLINK --> FADE_R_B: Modbus write mode=1
    TRI_COLOR_BLINK --> RANGE: Modbus write mode=2
```

## TODOS

### PERFORMANCE

- Consider power consumption optimization for battery-powered applications
- Investigate using DMA-based LED control to reduce CPU usage
- Add brightness control via Modbus to manage power usage

### SECURITY

- Validate Modbus values more strictly to prevent unexpected behavior
- Consider adding access control for mode changes

### COMPLIANCE

- Verify EMC compliance when LEDs change rapidly (potential for EMI)
- Ensure ADA compliance for visual indicators in public/commercial settings

### RECOMMENDATIONS

- Use adequate power supply for LED strips (60mA per pixel at full brightness)
- Consider adding a level-shifting circuit when connecting 3.3V microcontrollers to 5V LED strips
- Add physical protection for LEDs in industrial environments
- Implement custom modes for specific application requirements

## EXAMPLE

This example shows how to initialize and mount an LED Feedback component in an application:

```cpp
#ifdef PIN_LED_FEEDBACK_0
  ledFeedback_0 = new LEDFeedback(
      this,                  // owner
      PIN_LED_FEEDBACK_0,    // pin
      LED_PIXEL_COUNT_0,     // pixelCount
      ID_LED_FEEDBACK_0,     // id
      LED_FEEDBACK_0_MB_ADDR // modbusAddress
  );
  if (ledFeedback_0)
  {
    components.push_back(ledFeedback_0);
    Log.infoln(F("LEDFeedback_0 initialized. Pin:%d, Count:%d, ID:%d, MB:%d"),
               PIN_LED_FEEDBACK_0, LED_PIXEL_COUNT_0,
               ID_LED_FEEDBACK_0, LED_FEEDBACK_0_MB_ADDR);
  }
  else
  {
    Log.errorln(F("LEDFeedback_0 initialization failed."));
  }
#endif
```

### References