> For the complete documentation index, see [llms.txt](https://aedrox.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://aedrox.gitbook.io/docs/flight-controller/interactive-blocks/ardupilot/servos-relays.md).

# Servos / Relays

## 1. SERVOs

#### RGB Led&#x20;

The RGB LED pad is a servo output (SERVO9). By default it is set to be used as RGB LED (120)[^1]. **SERVO9\_FUNCTION** can be modified to be used to something else (eg: to control a servo motor)

#### Motors 1  to 8. (SERVO1\_  to SERVO8\_)

Motors are defined automaticaly by your FRAME\_TYPE and or FRAME\_CLASS.\
If not used for the motors (eg: Quad drone) the motors 5 to 8 can be used to other purposes (eg: to control a servo motor) by defining a specific **SERVOx\_FUNCTION** :&#x20;

Exemple : SERVO5\_FUNCTION : 29   (To control a retractable landing gear)

{% hint style="info" %}
SERVOx\_FUNCTION can be modified on this page  :  SETUP > Mandatory Harware > Servo Output\
But the CONFIG > Full Parameter List gives more options
{% endhint %}

<figure><img src="/files/9riGjtuBK2IIdxpPY2tz" alt=""><figcaption></figcaption></figure>

{% hint style="info" %}
For more informations on SERVOn\_FUNCTIONS, visit this [Ardupilot Wiki page](https://ardupilot.org/copter/docs/common-rcoutput-mapping.html)
{% endhint %}

***

## 2. RELAYs

General Purpose Input/Outputs (GPIOs) are used in ArduPilot for control of relays, actuators, LEDs, camera triggers, Start Button etc

#### GPIO1  (Relay1)

**RELAY1\_FUNCTION :** 1 \
**RELAY1\_PIN :** 81

#### GPIO2 (Relay4)

**RELAY4\_FUNCTION :** 1 \
**RELAY4\_PIN :** 82

#### VTX Power (Relay2)

**RELAY2\_FUNCTION :** 1 \
**RELAY2\_PIN :** 83\
This relay activate the flight controller 10V power supply. \
Low = Off. / High = On

#### Camera Switch (Relay3)

**RELAY3\_FUNCTION :** 1 \
**RELAY3\_PIN :** 84\
This relay activate the built in camera switch. \
Low = CAM1  / High = CAM2

{% hint style="info" %}
RELAYx\_DEFAULT : 0/1  (This paramater define the default state of relays : 0 = low / 1 = high)
{% endhint %}

### REMOTE CONTROL RELAYS

ALL relays can be remotely controlled. By setting the appropriate **RCx\_OPTION :** \
28 : Relay1\
34 : Relay2\
35 : Relay3\
36 : Relay4\
\
The 'x' should correspond to the remote channel number.\
Exemple : RC7\_OPTION : 34  -   Use CH7 of the transmitter to switch the 10V power supply on/off.

{% hint style="info" %}
SERVOs and RELAYs can be tested by using the Mission Planner virtual buttons Tab.
{% endhint %}

<figure><img src="/files/1ncANSQXetXR6oTEClGM" alt=""><figcaption></figcaption></figure>

[^1]:


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