Thank you. I was trying to find this earlier today.

I can’t draw worth a damn. Anyway, here’s Vin Diesel.

I have a Bose Soundlink Micro Bluetooth speaker that goes into a low energy standby anytime it’s not being used. I am able to connect to it and start playing music without pressing any buttons on the speaker. Sounds like what you are looking for. I imagine all their Soundlink speakers have BTLE (and they can be grouped).