Introduction
If you own a first-generation Google Home Mini, you probably appreciate its compact size and voice control capabilities. But as concerns about privacy and the desire for local control over smart home devices grow, many are looking for alternatives to cloud-dependent assistants. What if you could repurpose that little speaker into a fully open, offline smart home controller running Home Assistant? Thanks to an $85 open-hardware drop-in board, it's now possible to replace the Google Mini's internals with a Raspberry Pi–based system that runs Home Assistant—giving you complete control without sending data to Google. This guide walks you through the process step by step, from gathering materials to final configuration.
What You Need
Before you begin, ensure you have the following prerequisites and materials:
- A first-generation Google Home Mini (model GH-1 – the fabric-covered puck).
- The drop-in replacement board (e.g., the one from this open-hardware project). It typically includes a Raspberry Pi Compute Module 4 (or similar) and a custom PCB that fits the Mini's enclosure.
- MicroSD card (at least 16GB, Class 10 recommended) for Home Assistant OS.
- USB-C power cable (the board replaces the original power input).
- Small Phillips screwdriver (PH0 or PH00) for disassembly.
- Plastic pry tool or spudger to open the case without damage.
- Computer with an SD card reader and internet connection to flash Home Assistant.
- Home Assistant installation software (Balena Etcher or Raspberry Pi Imager).
- Optional but helpful: USB keyboard, HDMI display, or a serial console cable for initial setup.
Step-by-Step Guide
Step 1: Prepare the Home Assistant Operating System
Start by downloading the latest Home Assistant OS image from the official website. Use Balena Etcher or Raspberry Pi Imager to flash the image onto your microSD card. After flashing, insert the card into the slot on the drop-in board (if the board has an integrated slot) or keep it aside if the board requires a separate module.
Tip: For headless setups, you can configure Wi-Fi credentials by editing the network/my-network file on the SD card after flashing, following the Home Assistant documentation.
Step 2: Disassemble the Google Home Mini
Place the Mini upside down on a soft cloth. The base is held by clips; use a plastic pry tool to gently separate the rubber bottom ring from the fabric body. Work your way around until the ring pops off. Underneath, you'll find four screws securing the metal plate. Remove them with the screwdriver. Lift the fabric mesh covering to expose the original circuit board and speaker assembly. Carefully disconnect the ribbon cables and wires (note their positions for reference). Remove the original board completely.
Step 3: Install the Drop-in Replacement Board
Align the new drop-in board with the mounting holes. It should slot into the same space the original occupied. Reconnect the speaker wires (typically a simple two-pin header) to the board. If your board has a microphone, connect that as well. Secure the board with the original screws. Gently press the fabric back into place, ensuring no wires are pinched. Finally, snap the rubber base ring back on.
Step 4: First Boot and Initial Configuration
Connect the USB-C power cable to the board and plug it into a wall outlet. Wait about 5 minutes for the first boot (the board will blink lights). If you have a display or serial console, connect it now to watch the boot process. Otherwise, use the Home Assistant mobile app or visit homeassistant.local:8123 in a browser (on the same network) to discover the device. Follow the on-screen prompts to create an account, set a location, and enable integrations.
Step 5: Configure Audio and Voice Control
Once logged into Home Assistant, navigate to Settings > Devices & Services > Integrations. Look for the drop-in board's integration (e.g., “Google Home Mini Audio” or a generic “Raspberry Pi” audio). Enable the audio output so you can hear Home Assistant's voice responses. To use voice input, you'll need to set up a voice assistant such as Assist (built-in) or Rhasspy. Configure the microphone input if your board includes one.
Tip: Test the speaker by playing a TTS message from a simple automation: action: tts.google_say (or the equivalent for your chosen engine).
Step 6: Add Smart Home Devices and Automations
Now the fun begins. Add integrations for your existing smart home hardware: lights, switches, sensors, thermostats, etc. Use the Add Integration button in Home Assistant to search for supported brands. Create automations using the visual editor or YAML scripts. For example, set a motion sensor to trigger a light at sunset. With the new board, all processing stays local—no cloud dependency.
Tips for Success
- Back up before you start – The original Mini cannot be easily restored to stock if you break something. If you want to preserve the device's original function, consider sourcing a used unit.
- Heat management: The drop-in board may produce more heat than the original. Ensure good ventilation; you can add small rubber feet to the base to elevate it slightly.
- Microphone placement: If the board doesn't have an onboard mic, you can reuse the Mini's original microphone ribbon – check the board's documentation for pinout.
- Firmware updates: Keep the board's firmware up to date by visiting the project's GitHub page. Many boards support OTA updates via Home Assistant.
- Use a quality power supply: The board may draw up to 2.5A. A cheap USB charger can cause instability.
- Explore community add-ons: Home Assistant has a huge library of add-ons like Node-RED, ESPHome, and Frigate NVR that can extend your Mini's capabilities.
- Share your experience: Open-hardware projects thrive on community feedback. Post your build photos and suggestions on the project forum to help others.
With your converted Google Home Mini, you now have a compact, private, and powerful smart home hub that respects your data and runs entirely offline. Enjoy the satisfaction of giving old hardware a new life!