Hi-Link HLK-V20 $10 Voice Control Module with Microphone & Speaker

It has several output channels of 3.3V logic level control by means of turning on relays, lamps, cooling, heating, spa pump etc... also can also do variable PWM output on a couple of channels etc. Here in this demo, I&set it to 50Hz voltage mains frequency for light dimming, but you can set it to 1kHz or any other preferred frequency up to 40kHz. The potential applications for it are limitless, upon customisation.