HD11CTRL - HDMI In-line Controller with IR, RS-232, CEC, Signal Sensing & 12V Trigger Outputs - Prolites Sound, Light & Video
Amazon.com: BobWire DAT1 Adds a 12V Trigger! Compatible with SONOS Connect, Echo Link, ChromeCast Audio, TV, Anything with an Optical Audio Out. Auto Power On Amplifiers & Fans. NOT Compatible with AV
AV Amplifier Triggered HDMI Switch : 4 Steps - Instructables