1 Introduction

Modern gaming handhelds strive to deliver immersive tactile feedback. Typically, rumble or vibration events are triggered directly by the game software (for example, a predefined vibration pattern when an on-screen explosion occurs). If a game does not explicitly provide such haptic cues, some devices attempt to derive vibration feedback from the audio output. One common approach is to use an Audio Processing Object (APO) in the sound pipeline along with an embedded microcontroller algorithm to drive a vibration motor based on audio. This APO+EC method can monitor the game’s sound for bass or impact cues and activate the haptic motor accordingly. However, relying on audio alone has limitations: if the audio lacks obvious low-frequency components (explosions, deep hits, and so on.), the vibration feedback can feel weak or nonexistent. There can also be noticeable latency and inconsistent intensity when using only the audio stream to generate haptics.

To address these gaps, the TI DRV2605L haptic driver’s Audio-to-Haptic mode is implemented in a gaming handheld context. In Audio-to-Haptic mode, the DRV2605L continuously monitors an analog audio input (such as the game’s headphone output) and automatically drives an LRA based on the audio’s frequency and amplitude characteristics. Low-frequency audio content (bass beats, explosions, environment noise) is intelligently converted into vibration patterns, meaning even if the game doesn’t program any rumble, the background audio produces a tactile effect. The conversion algorithm (licensed from Immersion’s TouchSense®) makes sure these vibrations feel natural and in sync with the audio rather than just random buzzing.

In our implementation, the handheld’s audio codec outputs left and right audio channels, each fed both to speakers (or headphones) and to a DRV2605L configured in audio-to-vibe mode. An embedded controller (EC) on the device can also interface with each DRV2605L through I²C for configuration and to trigger specific haptic effects when needed. Figure 1-1 illustrates the dual-input haptic configuration: the audio path (green lines) and the EC control path (blue lines) both influence the DRV2605L haptic drivers.

Codec and EC-based left or right channel routing to dual DRV2605L drivers for haptic feedback in a gaming handheld. Each DRV2605L can receive an analog audio input (green) and I²C control signals (blue) from the embedded processor, supporting synchronized audio-driven and direct haptic feedback.

Figure 1-1 Dual DRV2605L Haptic Routing Through Codec and EC

This document is structured as follows:

• An overview the DRV2605L’s Audio-to-Haptic mode and the benefits
• Description of the hardware test setup and key configuration steps for using Audio-to-Haptic.
• Waveform results from lab tests are presented to analyze the LRA’s response at different audio frequencies and volumes.
• Sharing the behavior when switching modes – for example, toggling between audio-driven haptics and manual playback mode – and how to make sure of smooth transitions.
• Recommendations for integrating these modes in a product design