Answer Calls by Nodding with AirPods Pro in iOS 18

Apple’s iOS 18 introduces Siri Interactions, an accessibility and convenience feature that allows AirPods Pro users to manage incoming phone calls and announcements completely hands-free using head gestures. By utilizing advanced motion sensors and on-device machine learning, users can simply nod their head to accept a call or shake their head to decline it without speaking aloud or touching a screen. This guide explains the technology powering this feature, device requirements, and how to set it up for daily use.

The Technology Powering Head Gestures

The hands-free nodding feature relies on the built-in inertial measurement units (IMUs) located inside the AirPods. These include:

  • Accelerometers: Detect linear acceleration and gravitational pull to measure changes in motion.
  • Gyroscopes: Track rotational movement to gauge the exact tilt and angle of your head.

When an incoming call arrives, Siri announces the caller. The H2 chip inside the AirPods activates an advanced machine learning model trained to recognize intentional head movements. When you nod vertically, the sensors record the distinct up-and-down motion pattern and confirm your intent to answer. Conversely, a side-to-side rotation registers as a head shake, signaling the system to decline the call.

Because the processing occurs locally and in real time on the H2 chip, the response is instantaneous, and the algorithms filter out unintentional movements—such as walking, running, or normal head turns—to avoid accidental triggers.

System Requirements

To use head gestures to manage calls, you must have the following compatible hardware and software:

  • iPhone: Running iOS 18 or later.
  • AirPods: AirPods Pro (2nd generation) or AirPods 4 (both standard and Active Noise Cancellation models) powered by the H2 chip.
  • Firmware: Latest AirPods firmware compatible with iOS 18.

How to Enable Siri Interactions on iOS 18

While the feature is often enabled by default during the initial setup on iOS 18, you can manually verify or customize it through your iPhone settings:

  1. Wear your AirPods and ensure they are connected to your iPhone.
  2. Open the Settings app on your iPhone.
  3. Tap the AirPods tab near the top of the menu.
  4. Scroll down to the Siri section and select Head Gestures (or Siri Interactions).
  5. Toggle the switch to On.
  6. Follow the on-screen calibration prompts to test both the nod and shake motions.

Using the Feature in Practice

Once enabled, answering an incoming call requires no vocal commands:

  1. When a call comes in, Siri announces the caller's name or number through your AirPods.
  2. To answer, nod your head up and down firmly once or twice. The call will connect immediately.
  3. To decline, shake your head left to right. The call will be routed directly to voicemail or dismissed.

This feature also functions seamlessly with Siri message announcements, allowing you to dismiss incoming text alerts or confirm you want to reply using the same natural head movements.