Stepper Motor Control In ARC

Yes - ARC can control stepper motors, but the best implementation depends on what you want the stepper to do:

Recommended approach

1) For a head rotation stepper

Use the Stepper Servo robot skill.

That skill lets ARC treat a stepper like a servo using a virtual servo port (v0 to v99), which is a very clean fit for something like pan/tilt or head rotation.

• Skill: Stepper Servo
• Docs: https://synthiam.com/Support/Skills/Servo/Stepper-Servo?id=21134

With that setup, you can do things like:

Servo.setPosition(v1, 90)

or use the GUI and scripts together.

This is usually the best route if you want:

• repeatable positioning
• home/calibration support
• speed/acceleration control
• simple ARC integration

2) For a 4-wheel omniwheel drivetrain

I would not recommend using steppers directly through ARC Movement Panel unless you already have a dedicated stepper motor controller layer that handles:

• closed-loop or open-loop stepping
• acceleration/deceleration
• synchronized multi-axis motion
• homing / calibration
• motor current handling

For drivetrain motion, ARC’s Movement Panel is best when the hardware underneath already behaves like a movement system. Steppers can be used, but they usually need a proper motor controller architecture behind them.

ARC Movement Panels are designed to abstract the robot’s motion, but the actual motor control still needs to be provided by hardware or a skill that implements that movement behavior.

Hardware connection options

Option A: External USB/Serial stepper controller

This is often the most flexible choice for NEMA 17 motors.

Use:

• a microcontroller or dedicated stepper controller
• connect it to ARC via USB serial
• control it from ARC using:
  • an existing robot skill if available
  • or a custom robot skill if you need a special protocol

This is usually the better option if you want:

• high torque
• proper stepper driver support
• custom motion logic
• multiple motors coordinated together

If you go this route, ARC scripting with JavaScript or Python can be used to send commands to the device over serial.

Option B: EZ-B / IoTiny directly

If the stepper system is already handled by a supported robot skill, this can work well.

For example:

• Stepper Servo skill uses virtual servo ports
• ARC then commands the stepper like a servo
• the actual stepper driver hardware is handled by the skill/firmware layer

For IoTiny, keep in mind the port power is often unregulated on many I/O ports, so you must be careful with motor power and logic levels. NEMA 17 motors will definitely need proper external driver hardware - ARC/EZ-B should not drive them directly.

IoTiny hardware overview: https://synthiam.com/Support/Hardware/EZ-B-IoTiny

Robot Skills vs scripting

Use a Robot Skill when:

• the behavior is already supported
• you want UI-based configuration
• you want the Movement Panel or servo interface to handle the motion
• you want the easiest maintenance

Use JavaScript/Python scripting when:

• you need custom coordination logic
• you want to sequence multiple motors
• you need sensor-based decisions
• you want to translate joystick/head/drivetrain commands into custom stepper commands

Best practice

Usually the best design is:

• Robot Skill for the hardware interface
• JavaScript/Python for behavior and automation

That keeps ARC organized and easier to maintain.

My recommendation for your project

For the head

Use:

• Stepper Servo skill
• virtual servo port like v1
• script control if needed

For the omniwheel drivetrain

Use:

• a dedicated motor controller / microcontroller
• connect via USB serial
• build either:
  • a custom robot skill, or
  • a scripting layer that sends movement commands to the controller

If you want the drivetrain to participate in ARC’s Movement Panel ecosystem, then the cleanest route is to build a Movement Panel or use a skill that acts as the movement interface. ARC does support custom Movement Panel behavior.

Movement panels overview: https://synthiam.com/Support/ARC-Overview/movement-panels

If you want to build something custom

If there isn’t an existing skill for your stepper controller, Synthiam recommends building a custom robot skill:

https://synthiam.com/Support/Create-Robot-Skill/Overview

That would be the path if you want a specialized stepper drivetrain controller that integrates tightly with ARC.

Quick question

What stepper driver or controller are you planning to use?

For example:

• DRV8825 / A4988
• TMC driver
• Arduino-based controller
• USB stepper controller
• something else

If you tell me the exact hardware, I can suggest the best ARC architecture and whether you should use:

• Stepper Servo
• a Movement Panel
• JavaScript/Python
• or a custom robot skill