Lewansoul Servo icon Lewansoul Servo — Control LewanSoul LX-16A servos via ARC (EZ-B v4/IoTiny): assign virtual ports, read positions, set speeds, and enable continuous rotation. Try it →
Korea
Asked
1 Participant
Virtual Robot with two controllers

Virtual Robot With Two Controllers

ARC Skip to comments Jump to end

Running ARC on a LattePanda (Windows) with the onboard Arduino Leonardo flashed with the EZ-Genuino_Leonardo firmware and connected over USB. I checked DTR Enabled in the Connection config so the serial events fire correctly. Two micro servos for head pan/tilt are on the Leonardo (D3 and D5). I also have an external EZ-B v4 over Wi-Fi for the higher-torque arm servos (shoulder on D4, elbow on D5). Both controllers connect fine (Leonardo as EZB index 0 over USB, v4 as EZB index 1 over Wi-Fi), and I can move everything using servo controls and Auto Position frames without issues.

I added the Virtual robot skill to visualize all four joints. Here’s the snag: when I add servo markers, the selector only seems to bind to ports like D3/D4/etc without any obvious way to select the EZB index. The head markers (0.D3/0.D5) update perfectly, but the arm markers follow the Leonardo’s D4/D5 instead of the EZ-B v4’s D4/D5, or sometimes they don’t update at all if those Leonardo ports are unused. I tried renaming servos via the servo config/manager to HeadPan, HeadTilt, ArmShoulder, ArmElbow and then typing those names into Virtual Robot, but the field appears to only accept a port (and flags it invalid if I type a name). I also tried adding a second Virtual Robot instance hoping it would target EZB index 1, but I don’t see a board selection anywhere in the skill.

Is there a way to explicitly bind Virtual Robot servo markers to a specific EZB index (e.g., 1.D4) or reference a named servo rather than just a raw port so I can visualize joints across multiple controllers?


Related Hardware (view all EZB hardware)
Lattepanda
Lattepanda by DF Robot
LattePanda with Synthiam ARCx runs headless, loads EZB firmware on the built-in Arduino, and controls robots from any browser
Wi-Fi / USB
Servos 12
Camera
Audio
UART 1
I2C
ADC 5
Digital 12

Related Robot Skills (view all robot skills)
Thumbnail
Auto Position Movement Panel (Gait) by Synthiam
Create servo frames/actions to animate humanoid, hexapod or custom gaits with smooth transitions, SW ramping and directional control
Requires ARC
Movement Panels
Thumbnail
Virtual Robot by Synthiam
Display robot image with real-time servo position readouts and basic servo management including servo deletion
Requires ARC
Misc
Jump to end

ARC Pro

Upgrade to ARC Pro

Your robot can be more than a simple automated machine with the power of ARC Pro!

Author Avatar
PRO
Canada
Twitter YouTube GitHub
#1  

Yes - what you’re seeing is expected behavior in Virtual Robot right now.

Short answer

Virtual Robot servo markers bind to servo ports, not EZB indexes.
So a port like D4 is interpreted as the first matching servo control/board mapping, which is why it appears to follow the Leonardo’s D4/D5 instead of the EZ-B v4’s D4/D5.

What this means

  • Virtual Robot currently does not offer a direct way to specify:
    • 0.D4 vs 1.D4
    • or a named servo like ArmShoulder
  • It uses the servo port mapping from the connected skill, and duplicate port numbers across multiple controllers can become ambiguous.

Best workaround

To visualize joints across multiple controllers, I recommend one of these approaches:

Option 1: Use unique servo mappings

If possible, avoid duplicate port names across controllers in the same project.

For example:

  • Leonardo: D0, D1, D2, D3
  • EZ-B v4: D4, D5, etc.

That way Virtual Robot can resolve each servo unambiguously.

Option 2: Use separate visualization skills

If you need to keep duplicate port assignments, consider:

  • one Virtual Robot skill for the Leonardo-driven joints
  • another visualization approach for the EZ-B v4 joints

However, since Virtual Robot does not expose a board selector, it won’t cleanly split two devices in one instance.

Option 3: Create a custom robot skill

If you need a multi-board visualization that explicitly tracks:

  • board index
  • servo name
  • or a combined robot model

then the right long-term solution is to build a custom robot skill: https://synthiam.com/Support/Create-Robot-Skill/Overview

That would let you map ezbIndex + port exactly the way you want.

Important detail

Renaming the servo to ArmShoulder in ARC is helpful for your project organization, but Virtual Robot’s servo field currently expects a port identifier, not a friendly name. So your test makes sense, but it won’t bind the marker that way.

Recommendation

For your specific setup, I’d suggest:

  1. Keep the Leonardo joints on one set of unique ports
  2. Move the v4 arm servos to a different set of unique ports if possible
  3. Then map those unique ports in Virtual Robot

A couple questions

  • Are both controllers using the same port numbers intentionally because of existing wiring, or could you remap one side?
  • Do you want the Virtual Robot to show both boards in one model, or would separate visualizers be acceptable?

If you want, I can help you design a clean port mapping for both boards in ARC so Virtual Robot can track them reliably.

I am a customer support AI and still learning. Please verify important answers in our support documentation. For advanced AI features, use the AI Script Agent built into ARC.
Login to post a comment