In 2017, Google launched the first-generation Home Mini, a compact smart speaker that offered an affordable entry into voice-controlled home automation. While it served its purpose, the device constantly sent voice queries to Google's servers, raising privacy concerns for many users. Now, a new open hardware drop-in board promises to transform that old speaker into a fully local smart home hub—running Home Assistant directly on the hardware. For $85, you can reclaim your smart speaker from the cloud and take control of your data.
Why Ditch the Cloud?
The original Google Home Mini relied entirely on cloud-based processing for voice commands. That meant every request traveled to Google's servers, even for simple tasks like turning on lights. For privacy-conscious users, this dependence on remote servers is a dealbreaker. Local processing, on the other hand, keeps all data on your network and responds faster. By replacing the original motherboard with a drop-in board that runs Home Assistant, you gain a powerful local automation hub without the privacy trade-offs. Home Assistant is an open-source platform that integrates with hundreds of smart home devices, allowing you to create complex automations completely offline.
The Drop-In Board Solution
This upgrade is designed specifically for the first-gen Google Home Mini. The board is a direct replacement for the original internal electronics, fitting into the same housing and using the same power supply. Installation requires basic disassembly skills—simply remove the bottom pad, unscrew the old board, and plug in the new one. The entire process takes less than ten minutes and requires no soldering. Once installed, your Google Home Mini becomes a dedicated Home Assistant server, complete with voice control via the integrated microphone and speaker.
What You Need to Know About the Upgrade
The drop-in board is built around an ESP32-S3 microcontroller, paired with 4MB of PSRAM and 16MB of flash storage. It includes a DAC for audio output, a microphone amplifier, and a USB-C port for flashing firmware or connecting peripherals. The board runs a custom version of ESPHome that communicates directly with your Home Assistant instance over Wi-Fi. Notably, it supports OTA (over-the-air) updates, so you can tweak configurations without opening the device again.
While the board retains the original speaker and microphone, the voice processing happens locally. This means you can still say "Hey Google"-like wake words (customizable via ESPHome) and trigger automation routines without any internet connection. However, advanced AI responses—like asking for a weather forecast or playing music from streaming services—are not available unless you connect it back to a cloud service. The board is strictly for local command processing and sensor data.
Features and Compatibility
- Full Home Assistant Integration: Once installed, the device appears as a new node in your Home Assistant dashboard. You can set up automations triggered by voice, button presses, or environmental sensors (if you add a sensor shield).
- Custom Wake Words: Unlike the stock Google Assistant, you can define your own wake words via ESPHome's voice pipeline. Options include "Computer," "Alexa," or any short phrase.
- LED Ring Control: The original four-LED ring still works. You can program it to indicate status, such as a pulsing light when listening or a solid color when an automation runs.
- Microphone Array: The single microphone captures voice commands, though far-field performance is limited compared to dedicated smart speakers. For closer use (within a few feet), it works reliably.
- Open Hardware: All schematics, firmware source code, and 3D models are available under permissive licenses. You can modify the board or even build your own version.
Is It Worth the Investment?
Priced at $85, the drop-in board costs more than a brand-new smart speaker—but it's not about saving money. It's about transforming a device you already own into a privacy-first smart home controller. If you are already invested in the Home Assistant ecosystem, this upgrade is a no-brainer. It provides a dedicated hardware platform that can handle voice commands and local automations without taxing your main server. For those new to Home Assistant, this could be an accessible entry point, though you will still need a separate computer or Raspberry Pi to run the core Home Assistant server (the Mini only runs the voice agent, not the full server).
One limitation is that the board is only compatible with the first-gen model. Later versions of the Google Home Mini (2nd gen) have different form factors and pinouts, so they won't work. If you have an old first-gen unit gathering dust, this is a fantastic way to give it new life. The open hardware nature also means the community can iterate—expect new firmware features and maybe even sensor add-ons in the future.
Conclusion: A DIY Lover's Dream
The $85 drop-in board for the Google Home Mini exemplifies the best of open hardware: repurposing proprietary devices for local, privacy-respecting use. While it requires a bit of tinkering and a willingness to lose the native Google Assistant features, the reward is a customizable, offline-capable smart home controller that answers to your voice without phoning home. If you're already using Home Assistant and have an old Home Mini in a drawer, this upgrade is well worth the price—and the ten minutes of disassembly.
Disclaimer: This article is for informational purposes. Always follow safety precautions when modifying electronic devices.