ESPica32: A Standalone ESP32 Radio for Tuning Any KiwiSDR with No PC or Phone
Thank you to Ivan (LU8MIL) from the ‘Radio Bunker’ YouTube channel for writing in and sharing ESPica32, a standalone ESP32-based radio that tunes into any public KiwiSDR in the world with no PC or phone needed. The name is a tribute to the Spica, a pocket transistor radio that was hugely popular in Argentina.
The build uses just four parts: an ESP32-WROOM-32, an SH1106 OLED display, a rotary encoder, and a MAX98357A I2S amplifier with a small speaker. A single encoder controls frequency, volume and mode (LSB, USB, AM, CW and FM). A web page served by the ESP32 handles Wi-Fi setup, KiwiSDR server selection and full remote control, and also includes a diagnostic for tracking down audio dropouts.
Ivan notes that distant KiwiSDRs initially cut out because the ESP32 couldn’t keep up with uncompressed audio. Switching to the KiwiSDR’s ADPCM compression fixed this, and a Kiwi in Argentina now plays cleanly from Germany at about 260 ms ping. The Arduino IDE sketch and wiring diagram are available on Ivan’s Todo-SDR blog, and the Spanish-language video below shows the build and a demo (English subtitles are available).
