Move Both Pistons Simultaneously

Yes - the cleanest way to make both pistons move together from the Movement Panel is to have ARC treat one actuator as the master and the other as a follower, or to build a small custom motion script/skill that drives both ports at once.

Since you’re using the EZ-Robot head in ARC and your ports are D4 = right and D5 = left, here are the best options:

Option 1: Use a servo link setup if both pistons are servo-driven

If each piston is controlled by a servo output, the easiest solution is to use a skill like Relative Servos:

• Add Relative Servos to the project
• Set one piston as the Master
• Add the second piston as a Slave
• Set the ratio to:
  • 1 if both should move in the same direction
  • -1 if one must mirror the other

Steps

1. In ARC, go to Project > Add Robot Skill
2. Add Relative Servos
3. Open the skill’s settings from the kebab menu
4. Set:
   • Master = D4 or D5
   • Slave = the other port
   • Ratio = 1 or -1 depending on the mechanism

This way, moving one servo automatically moves the other.

More here:

• Relative Servos skill: https://synthiam.com/Support/Skills/Servo/Relative-Servos?id=16052

Option 2: If these are movement directions, use a custom Movement Panel

If your pistons are part of a custom movement behavior and the standard Movement Panel only drives one at a time, then the right solution is to create a custom robot skill or custom Movement Panel that sends both commands together.

That way, when ARC sends Forward / Reverse / Stop, your skill can do:

• D4 = move
• D5 = move
• both at the same time

Synthiam’s movement system is designed so a Movement Panel owns the direction logic, and you can create your own if needed:

• Movement Panels overview: https://synthiam.com/Support/ARC-Overview/movement-panels
• Create a robot skill: https://synthiam.com/Support/Create-Robot-Skill/Overview

Option 3: Use a script in the Movement Panel action

If your current Movement Panel is something like an Auto Position or custom scripted control, you can have the movement direction call both ports in the same script.

Example JavaScript idea:

function forward() {
  Digital.set(D4, true)
  Digital.set(D5, true)
}

function reverse() {
  Digital.set(D4, false)
  Digital.set(D5, false)
}

function stop() {
  Digital.set(D4, false)
  Digital.set(D5, false)
}

If your pistons are actually servos, then the script should use Servo.setPosition() instead of Digital.set().

Example:

function moveBoth(position) {
  Servo.setPosition(d4, position)
  Servo.setPosition(d5, position)
}

Important note

A standard Movement Panel can only be the robot’s locomotion owner, but it does not mean you’re limited to one actuator. The issue is usually the configuration of the control, not ARC itself. In other words, ARC can absolutely drive both sides together - it just needs the correct setup.

What I need to know to give you the exact fix

Are those pistons controlled as:

1. Servos on D4 and D5
2. Digital outputs driving a piston driver/relay
3. Part of an Auto Position or other movement skill

If you tell me which one, I can give you the exact ARC setup or a ready-to-paste JavaScript script for it.