We don’t know if Batman has a keychain for the keys to the Bat mobile, the Bat copter, and all his other vehicles. But we are guessing if he did, it didn’t look like the one [krishnan793] picked up cheap. It had a little button that lit up some LEDs and played a little tune. [Krishnan] thought he could do better with an ESP8266. After chopping up some headphones and adding a LiPo battery, he wound up with an improved key chain you can see in the video below. The first video is the before video. The second is after the modification. Sure, it is only a small improvement on LEDs and a simple tune, but now it is hackable to do more interesting things if you want to take the trouble to do so.
Although taking out the existing electronics left some room inside the Batman body, it still took a Dremel tool to cram everything in. Not that there’s much: an ESP01 module, three surface mount LEDs, and a resistor. The battery and the charger take up as much space as the rest.
[Krishnan] has more plans for the key chain, including allowing it to be a hotspot so you can download a new tune. Granted, if you had a color 3D printer, you could probably just roll your own outside and inside, but hacking an existing cheap toy is cool, too.
Maybe it is time to revisit the classic Bat cave secret switch with an ESP8266, too. Batman was known for having a veritable Swiss Army knife in his belt, so maybe this ESP8266 project would be more appropriate.