LED Indications and Tones

As soon as the controller powers up its LED starts reporting status: whether it has a position fix, whether it can arm, and which step it is stuck on. With the buzzer built into a NEO series GPS you also get audible feedback. Reading the light and the sound tells you most of what you need, without a ground station.

NOTE

Everything below assumes the ArduPilot default LED behaviour, i.e. the NTF_LED_OVERRIDE parameter is left at its default 0 (Standard). If you change it, colours and flash patterns follow your own settings.

The blinking animations come from the official ArduPilot documentation and show exactly what the flight controller displays; the tones are the official audio files — click Play to listen.

NEO Series LED & Buzzer Reference

NOTE

The LED and buzzer on the NEO series extend the controller's status indications. The buzzer is built into the NEO series GPS only — the controller itself has no buzzer. If you add your own external LED and buzzer, the indications below still apply.

Light	Sound / Tone	Meaning
	None	Initialising gyroscopes — hold the vehicle still and level
	None	Disarmed, no GPS lock. Auto, Loiter and RTL modes require GPS
	None	Armed, but no GPS lock
	Quick double tone when disarming 0.8s	Disarmed (ready to arm), GPS lock acquired
	None	Same as above, but GPS is using SBAS for a more accurate position estimate
	Single long tone when arming 3.2s	Armed, GPS lock acquired — ready to fly
	Repeated short low beeps 1.1s	Pre-arm checks failing, the system refuses to arm
	None	Radio failsafe active
	Rapid continuous beeping 7s	Battery failsafe active
	High-high-high-low (dah-dah-dah-doh) 1.9s	GPS glitch or GPS failsafe active
	Rising tone 1.7s	EKF or inertial navigation failure
	None	ESC calibration mode

Colour at a Glance

The controller carries a single RGB status LED; colour is the quickest way to read it.

Colour	Rough meaning
Green	Normal, ready to fly
Blue	No GPS lock
Yellow	Warning: pre-arm checks failing, or a failsafe is active
Red	Fault
Red/blue alternating	Initialising

The one-line version: flashing green = ready to arm, solid green = armed.

Power-Up Sequence

1. The first few seconds: red and blue alternate while the gyroscopes initialise. Keep the vehicle still and level until it stops.

2. Waiting for a fix: slow green = ready to arm; slow blue = still waiting for satellites; double yellow = pre-arm checks failing.

3. After arming: solid green means normal flight; as soon as it turns yellow or red, check the ground station.

Other Tones

Beyond the tones that accompany the lights above, there are a few standalone sounds:

When	Sound	Listen
Power-up	One short beep — start-up OK	1.8s
Power-up	Low continuous tone — start-up failed	1.3s
Disarm	Two short beeps	0.8s
Barometer fault	Continuous short beeps; altitude hold and landing are affected	1.8s
No SD card	SOS (three short, three long, three short), repeats from power-up	6.6s
Parachute release	A distinctive melody	1.1s
Lost vehicle	Continuous alarm, helps you find the aircraft after radio loss	3.9s

TIP

Buzzer volume is set by the on-board circuit; most models have no software volume control. Do not disable the arming and disarming tones — when the aircraft is out of sight they are your only feedback.

FAQ

1. Yellow double flash and it refuses to arm?

• Pre-arm checks are failing; this is not a fault. Connect a ground station and read the PreArm message — in most cases it comes down to an uncalibrated compass, no GPS fix, or an uncalibrated radio.

2. The LED is green but the ground station shows no GPS?

• Green only means "position valid, ready to arm"; the satellite count is on the ground station. If that count is low, check whether you are indoors or the antenna is blocked.

3. No light and no sound after power-up?

• Check the power supply (USB or battery) and the power module wiring. If a controller stays silent after a firmware change, the firmware may not match the model — reflash the correct firmware for it.

4. SOS tone right at power-up, everything else is fine?

• The SD card is missing, not seated properly, or not formatted. The controller stores logs on the card; leaving it out means losing flight logs, so fit a good card formatted as FAT32.

5. The LED colour does not match this page?

• Check that NTF_LED_OVERRIDE is 0. On some models the RGB LED is on an external strip, and the strip has its own lighting settings.