Inmoov Head Movements

Yes - a PCA9685 servo driver is a great fit for an InMoov head, and it can be used with ARC.

Best way to connect it

The PCA9685 does not connect directly to ARC/PC.
It connects through your controller using I2C.

So your signal path is:

ARC EZB / controller PCA9685 servos

If your Arduino Mega is acting as the EZB/controller in ARC, then yes, that can work as long as ARC is connected to the Mega in a way ARC supports and the board exposes I2C properly.

Important clarification

There are two different ideas here:

1. ARC on the PC talking to an EZB/controller

ARC is the software brain, and the controller is the hardware bridge to servos/sensors.

2. PCA9685 on the I2C bus of that controller

The PCA board is just a servo expander. ARC never talks to it "directly" over USB or WiFi.

Recommended ARC setup

For the cleanest integration in ARC:

• Add your connection skill for the controller
• Add the PCA9685 servo Driver robot skill
• Configure the PCA skill to the correct:
  • I2C address
  • Min/Max pulse width
  • Port range (V0-V15, V16-V31, etc.)

Then any ARC skill that commands servos can use those virtual servo ports.

For example:

• Auto Position
• Inverse Kinematics
• scripts
• speech gesture motions
• custom robot skills

How it integrates with your head

If your InMoov head uses many servos, the PCA9685 lets ARC treat them like normal servo ports:

• V0 to V15 for one PCA board
• V16 to V31 for a second board
• and so on

That means you can build out the head motions without running out of native servo pins.

If you use an Arduino Mega

This depends on how the Mega is connected to ARC:

If ARC sees it as a supported EZB-style controller

Then yes, you can use it as the controller that communicates with the PCA9685 over I2C.

If it’s only a plain Arduino sketch over serial

Then ARC won’t automatically treat it like an EZB unless you’re using a supported connection path/skill.

So the key question is:
Are you connecting the Mega as an ARC-supported controller, or are you planning to upload your own Arduino code and have ARC talk to it separately?

Wiring overview for PCA9685

Typical I2C wiring:

• SDA SDA
• SCL SCL
• GND GND
• VCC 3.3V or 5V logic
• Servo power (V+) from a separate servo power supply

Very important:

• The servos should not be powered from the controller’s logic power
• The PCA board and controller must share ground

ARC skill setup

In ARC:

1. Add the PCA9685 servo Driver skill
2. Open its settings using the three-line/kebab menu
3. Set:
   • I2C address
   • servo pulse limits
   • port range
4. Connect your controller
5. Test a servo using a virtual port like V0

Good reference

PCA9685 skill docs:
https://synthiam.com/Support/Skills/Servo/PCA9685-Servo-Driver?id=23154

Also useful:

• ARC download: https://synthiam.com/Products/ARC
• Create custom skills if you need special behavior: https://synthiam.com/Support/Create-Robot-Skill/Overview

My recommendation for your InMoov head

If you want the least complicated path:

• Use ARC
• Use a supported EZB-style controller
• Use PCA9685 for the extra head servos
• Keep speech/vision/jaw as separate ARC skills if that’s already working

That’s a very normal ARC architecture for an InMoov build.

If you want, I can help you map out:

1. which servos should go to which V-port, or
2. how to wire the PCA9685 to your exact controller, or
3. how to configure the PCA skill in ARC step-by-step.

If you share which controller firmware/hardware you’re actually using with the Mega, I can tell you the exact ARC setup.