Espruino Puck.js

https://www.adafruit.com/products/3372

I stumbled upon this a week ago and was back and forth on its usefulness and its price. I do like the form factor and how self contained it is. It uses a CR2032 battery which is super common and... "All LEDs lit, 100% CPU usage running JavaScript - 10mA" and a CR2032 battery is 190mA, meaning ~19 hours at max usage. It only supports BLE so we'd need to figure out a slightly different approach than what we've been doing with the ESP8266 so far. There is Web BlueTooth which is a viable option and could very easily hook into our ESP JS libraries with some modifications. It already has an IR LED and has solder pads for additional components. I was really excited about this, until I saw the price, $40.

I've been looking at this as a possible option for passive recording while I'm in the parks as well. It looks "normal" enough and it would last all day. However, I think the big reason I'm attracted to this is the fact that it has a battery already attached to it and a nice case, both of which we could do ourselves if we gave it enough time. The biggest issue is having enough RAM to work with or being able to dump the memory into a larger device often enough. OR! Possibly hashing the command and checking for duplicates that way so we're only getting unique commands. That still relies on being able to dump the recordings often enough though. It all relies on JS so I don't know how memory is handled.