CAST-1 Audio Casting

Apollo Automation CAST-1 Audio Casting Device

The Apollo CAST-1 turns regular powered speakers, amplifiers, and AV receivers into Home Assistant / Music Assistant endpoints. Plug it into a 3.5mm line input, connect it over Wi-Fi, and stream music, announcements, alarms, and whole-home audio to the speakers you already own. It runs open-source ESPHome firmware and works locally — no cloud required.

KEY FEATURES

• Makes existing speakers smart with Home Assistant and Music Assistant
• ESP32-S3 with ESPHome firmware
• TI PCM5122 32-bit stereo DAC
• 3.5mm analog line-out for powered speakers, amps, and receivers
• SendSpin support for synchronized multi-room audio
• Home Assistant announcements, alarms, and media playback
• Bluetooth proxy capable
• Onboard RGB status LED
• GPIO pads for an addressable RGB LED strip
• 100% local, open-source firmware

SPECIFICATIONS

Processor:

• MCU: ESP32-S3
• Flash: 16 MB
• PSRAM: 8 MB

Audio:

• DAC: Texas Instruments PCM5122
• 32-bit stereo
• 112 dB SNR / dynamic range
• Output: 3.5mm analog line out (2.1 VRMS full scale)

Connectivity:

• Wi-Fi 2.4 GHz
• Bluetooth / BLE
• USB-C for power and programming

Expansion:

• Solder pads for 5V, GND, and IO1
• Onboard RGB LED

Power:

• USB-C, 5V / 1A

Physical:

• Size: 45 × 45 × 15 mm (1.8 × 1.8 × 0.6 in)

Software:

• ESPHome (open source)
• Home Assistant
• Music Assistant via SendSpin
• Home Assistant Bluetooth Proxy
• Local control only — no cloud required

What's Included:

• 1 × Apollo CAST-1 Audio Casting Device

NOTES

• Connects to powered speakers, amplifiers, or AV receivers through a 3.5mm line input
• Ideal for adding Home Assistant audio, announcements, and multi-room music to existing speaker setups
• Firmware can be managed and customized through ESPHome