Skip to main content

LED Reference

Overview

iReporter can drive hardware LEDs on an Arduino or compatible serial device to provide visual indicators for active crash/incident timers and the Top X Cars approach warning.

Serial Protocol

iReporter communicates with the serial device using a simple text-based protocol over the configured COM port at 9600 baud. Each LED command is a single line in the format:

LED;{COLOUR};{STATE};

Where:

  • COLOUR — one of: RED, BLUE, GREEN, AMBER
  • STATE — 1 to turn the LED on, 0 to turn it off

Examples:

LED;RED;1;      (turn red LED on)
LED;RED;0;      (turn red LED off)
LED;AMBER;1;    (turn amber LED on)

LED Assignments

FeatureSettingBehaviour
Crash CaptureTimeout LED (in Crash Capture settings)Steady ON while a crash is active,active OFF(timed whenmode) timeout— expiresOR — brief 600ms flash on capture (No Timeout mode)
Incident CaptureTimeout LED (in Incident Capture settings)Steady ON while an incident is active,active OFF(timed whenmode) timeout— expiresOR — brief 600ms flash on capture (No Timeout mode)
Top X ApproachingApproach LED (in Top X Cars settings)ON when a top-X car is within the approach gap AND more than 1 lap ahead

Timed vs No Timeout LED Behaviour

The crash and incident LEDs behave differently depending on the timeout setting:

Timeout SettingLED BehaviourData Cleared When
Timed (1–60s)Stays ON for the full timeout duration, then turns OFFTimeout expires
No Timeout (0)Flashes ON for 600ms on detection, then turns OFFNext crash/incident is detected (overwrites previous)

The brief flash in No Timeout mode confirms that a crash or incident has been captured without implying it is still pending — the data remains available in message variables indefinitely.

Colour Options

OptionDescription
NoneNo LED output for this feature
REDRed LED
BLUEBlue LED
GREENGreen LED
AMBERAmber / orange LED

Notes

  • iReporter only sends a new LED command when the state changes — it does not repeatedly send the same command.
  • Multiple features can use different colours simultaneously (e.g. RED for crash, AMBER for incident).
  • If two features are assigned the same colour, the last state change wins. It is recommended to assign a unique colour to each feature.
  • The COM port and baud rate (9600) are fixed. Ensure your Arduino sketch listens on 9600 baud and parses the LED;COLOUR;STATE; format.
Back to top