Got a first-gen Google Home Mini collecting dust? The MiciMike Home Mini Drop-in Board is an open source replacement PCB that slots directly into the original enclosure and speaker hardware, swapping out Google's cloud-dependent guts for a fully local voice assistant powered by Home Assistant. The hardware design is published on GitHub under the CERN-OHL-S v2 copyleft license, so you can inspect the schematics or even fabricate your own board, with the requirement that any derivatives remain equally open.
At the heart of the replacement board is an ESP32-S3 handling primary processing duties with WiFi 4 and Bluetooth 5.0 connectivity, paired with a XMOS XU316 dedicated audio processor. Two onboard microphones provide voice input with noise suppression and echo cancellation. The board ships pre-flashed with ESPHome for Home Assistant integration and supports on-device wake word detection, meaning your voice data never leaves your local network. The XMOS audio firmware is maintained as a separate open source project at esphome/voice-kit-xmos-firmware and can be built and flashed on Linux using the XMOS XTC toolchain and dfu-util for users who want to customize the DSP pipeline. Music playback is handled through Music Assistant, and multi-room audio synchronization is available via Snapcast and Sendspin integration.
The installation process involves removing the original Google Home Mini PCB entirely and dropping in the MiciMike board, with a step-by-step guide available on the project wiki. If you do not already own a Google Home Mini, dedicated options like the Home Assistant Voice PE at $59 (€54) or the Satellite1 dev kit at $70 (€64) offer a simpler path to local voice control. The MiciMike board is available for pre-order at $85 (€78) through Crowd Supply.
