Offline AI Voice Assistant Built with Raspberry Pi 5 Enables Complete Data Privacy

A technology enthusiast in Hong Kong has developed a portable AI-powered voice assistant that operates entirely without the need for cloud connectivity or internet access. The device is constructed around the Raspberry Pi 5 single-board computer, offering users a fully local solution for voice interaction and artificial intelligence applications.

The project, which is detailed in a series of online videos, provides comprehensive instructions for those interested in creating a similar device. Key components of this build include the Whisplay HAT, which incorporates a compact 1.69-inch color display, and the Pi Sugar 3 battery pack, offering a capacity of 5000 mAh to ensure prolonged operation away from external power sources.

High-Performance AI Accelerator

To meet the demanding computational requirements of local AI processing, the creator integrated the LLM-8850 AI accelerator card. Designed by M5Stack, a manufacturer based in China, this M.2-format card is tailored for advanced tasks such as running large language models (LLMs), computer vision, and audio applications on resource-constrained hardware like the Raspberry Pi 5. The LLM-8850 delivers up to 24 trillion operations per second (TOPS), making it capable of handling sophisticated AI workloads offline. However, the card's price point, at US$139, is notably higher than that of the Raspberry Pi 5 itself, and it produces significant heat during operation.

Effective thermal management proved essential for stable performance. After testing multiple configurations, the builder settled on using a Waveshare Dual M.2 HAT to mount the AI accelerator. This solution not only enhances cooling but also allows for future upgrades, such as adding a solid-state drive underneath the display module.

Additional Features for Enhanced Functionality

In a recent upgrade, the device was fitted with a camera module--specifically, the Raspberry Pi Camera v3--enabling visual recognition capabilities. The project also features a custom-designed enclosure, improving portability and daily usability.

The offline voice assistant employs a suite of open-source AI tools for its core functionality. Local language processing is handled by a model from the Ollama project, while speech-to-text conversion is managed by Whisper. For text-to-speech output, the Piper tool is utilized. This software combination allows for seamless, entirely local interaction between user and device.

Privacy and Data Security Advantages

While Raspberry Pi-based voice assistants have been explored in the past, previous solutions often relied on cloud services for processing. The current build distinguishes itself by performing all computations and data processing on the device itself. As a result, user data remains on the hardware and is not transmitted to external servers unless explicitly permitted by the user. This approach ensures heightened privacy and data security, addressing concerns associated with cloud-based voice assistants.

Implications for DIY and Open-Source Communities

This open-source project highlights the growing potential for do-it-yourself AI solutions that prioritize user control and privacy. By providing detailed documentation and using widely available components, the project enables enthusiasts and developers to create their own secure, offline AI voice assistants. The device demonstrates how advances in hardware accelerators and open-source AI models are making sophisticated, private voice interaction accessible to a broad audience.