---
title: "StatusLight Component"
description: "A component for controlling and monitoring status lights with blinking capability"
keywords: ["status", "light", "LED", "feedback", "modbus", "blinking"]
---

# StatusLight

**Path**: [`src/components/StatusLight.h`](../src/components/StatusLight.h)

**Revision History**: Initial documentation

The StatusLight component provides functionality to control and monitor status indicators such as LEDs. It supports three states: OFF, ON, and BLINKING, with configurable blinking intervals. It integrates with the Modbus system for remote monitoring and control.

## Requirements

- Digital output pin for connecting the status light/LED
- STATUS_BLINK_INTERVAL defined in configuration (default: 800ms)
- Optional Modbus address for network control

## Features

- Three operation modes: OFF, ON, and BLINKING
- Configurable blinking intervals
- Modbus integration for remote monitoring and control
- Serial bridge interface for local control
- Automatic pin state management during state transitions

## Dependencies

- [Component](../src/Component.h) - Base class for all components
- [Bridge](../src/Bridge.h) - For serial command interface
- [ModbusTCP](../src/modbus/ModbusTCP.h) - For Modbus network integration

```mermaid
graph TD
    StatusLight --> Component
    StatusLight --> Bridge
    StatusLight --> ModbusTCP
```

## Behaviour

The StatusLight component manages a digital output pin with three possible states: OFF, ON, and BLINKING. When in BLINKING state, it toggles the output at the configured interval.

```mermaid
stateDiagram-v2
    [*] --> OFF
    OFF --> ON: set(1)
    ON --> OFF: set(0)
    OFF --> BLINK: status_blink(true)
    ON --> BLINK: status_blink(true)
    BLINK --> OFF: status_blink(false) + state==OFF
    BLINK --> ON: status_blink(false) + state==ON
```

## TODOs

### Performance

- Consider using non-blocking timers for more precise blinking intervals
- Evaluate performance impact of continuous polling in the loop method

### Security

- Validate input parameters in public methods to prevent unexpected behavior
- Consider adding authentication for Modbus write operations

### Compliance

- Ensure proper error handling for hardware failures
- Add support for different blinking patterns for various status indications

### Recommendations

- Use consistent addressing scheme when multiple status lights are used
- Consider using PWM for dimming capability in future versions
- When using with critical systems, consider adding a watchdog timer

## Example

The following example shows how to initialize and use a StatusLight component:

```cpp
#ifdef STATUS_WARNING_PIN
  StatusLight* warningLight = new StatusLight(
      this,                  // owner
      STATUS_WARNING_PIN,    // pin
      COMPONENT_KEY_FEEDBACK_0, // id
      MB_MONITORING_STATUS_FEEDBACK_0 // modbusAddress
  );
  if (warningLight)
  {
    components.push_back(warningLight);
    Log.infoln(F("Warning Status Light initialized. Pin:%d"), STATUS_WARNING_PIN);
  }
  else
  {
    Log.errorln(F("Warning Status Light initialization failed."));
  }
#endif

// Later in the code, control the status light:
warningLight->on();       // Turn on the light
warningLight->off();      // Turn off the light
warningLight->setBlink(true);  // Make it blink
```

### References

${DOXYGEN_PLACEHOLDER}

${VENDOR_PLACEHOLDER}