Drag vertically to control a servo within set min/max limits; center, release, invert, and mirror to other servos. For 3-wire GVS servos.
How to add the Vertical Servo robot skill
- Load the most recent release of ARC (Get ARC).
- Press the Project tab from the top menu bar in ARC.
- Press Add Robot Skill from the button ribbon bar in ARC.
- Choose the Servo category tab.
- Press the Vertical Servo icon to add the robot skill to your project.
Don't have a robot yet?
Follow the Getting Started Guide to build a robot and use the Vertical Servo robot skill.
How to use the Vertical Servo robot skill
What this skill does: The Vertical Servo skill lets you move a servo by dragging your mouse up and down inside the skill window. The servo will only move within the Minimum and Maximum limits that you set in the skill settings (both are 90 by default).
Important note about startup position: Like all ARC robot skills, this skill does not remember the last servo position after you close ARC or disconnect. If you want your servo to move to a known safe position when the robot connects, create an initialization script using the
Connection Skill.
Main Window
The main window is where you manually move (and test) the servo.
1) Position Adjust / Display
- Drag to move: Click and hold the left mouse button on this area, then drag up or down to move the servo.
- Type an exact value: Right-click to enter a position using the keyboard.
- What the number means: The display shows the current servo position in degrees (typically 1–180).
- Safety limits: Even if you type a value, the servo will still stay within the Minimum and Maximum limits set in Settings.
2) Release Button
Releases power/holding torque from the servo so it no longer “holds” its position. If your servo and linkage allow it, you can gently move the horn/gear by hand.
Tip: Use Release when you need to reposition a mechanism manually. Avoid forcing the servo if it feels stuck.
3) Center Button
Moves the servo to the midpoint between your Minimum and Maximum settings.
Example: Minimum = 10, Maximum = 140 → Center = 75.
Settings
Use the Settings panel to choose the correct servo port and to set safe movement limits.
This is the name of the skill as it appears in your ARC project. You can rename it to something like Neck Tilt or Camera Up/Down.
Note: Changing the title also changes the name used in the
controlCommand() for this skill.
Select which controller board the servo is connected to (for example, if you have more than one servo controller or microcontroller connected to ARC).
Beginner tip: If you only have one board connected, this is usually Board 0 (or the first option in the list).
Beginner tip: If you only have one board connected, this is usually Board 0 (or the first option in the list).
Choose the digital port (signal pin) where your servo’s signal wire is connected.
Reminder: Servos typically have 3 wires: Ground, Voltage, and Signal (GVS). Make sure the signal wire is on the correct pin for the port you select.
Reminder: Servos typically have 3 wires: Ground, Voltage, and Signal (GVS). Make sure the signal wire is on the correct pin for the port you select.
Sets the lowest angle the servo is allowed to move to using this skill.
- Drag with the left mouse button to adjust.
- Right-click to type the value.
Why this matters: Use Minimum/Maximum to prevent the servo from hitting mechanical stops or overextending a linkage.
Sets the highest angle the servo is allowed to move to using this skill.
- Drag with the left mouse button to adjust.
- Right-click to type the value.
Beginner workflow: Start with a small safe range (example: 80–100), test movement, then expand the range slowly.
Lets you select additional servos to mirror the same movement as the “master” servo controlled by this skill.
Example use: If your robot has two servos lifting the same mechanism (left and right side), you can mirror them so they move together.
Example use: If your robot has two servos lifting the same mechanism (left and right side), you can mirror them so they move together.
Tip: If mirrored servos move opposite directions, enable Invert Direction on the servo that needs to reverse.
Reverses the direction the servo moves for a given position value.
Example: Normally, a value of 180 might move the servo “up.” With Invert Direction enabled, sending 180 will move it “down.”
Example: Normally, a value of 180 might move the servo “up.” With Invert Direction enabled, sending 180 will move it “down.”
When to use: Useful when a servo is mounted flipped or when two mirrored servos need to move in opposite physical directions to achieve the same motion.
How to Use Vertical Servo (Beginner Steps)
-
Add the skill to your project:
In ARC, go to Project → Add Skill → Servo → Vertical Servo.
-
Open the skill settings:
Select the correct Board Index (the controller your servo is plugged into).
-
Select the servo port:
Choose the digital Port that matches where the servo signal wire is connected.
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Set safe movement limits:
Adjust Minimum and Maximum. Start with a small range and increase slowly to avoid binding.
-
Move the servo from the main window:
Click-and-drag up/down in the Position area (or right-click to type an exact angle).
Video
Requirements
- A standard 3-wire GVS (Ground-Voltage-Signal) 180° servo motor.
- A compatible controller supported by ARC that can output a servo signal on the selected digital port.
Resources
If the servo does not move: double-check wiring (GVS order), board/port selection, and make sure your controller is connected in ARC.
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