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.
One of the best feature of the ESP8266 is its ability to self-host a web server, allowing for fairly complicated user interactions. The dEEbugger by [S-March] is a nifty little ESP8266 based device with a plethora of features in a small package.
The USB-powered device has a web user interface that enables it to be used as a low-bandwidth oscilloscope, I2C terminal, or UART terminal. As a scope, you may connect to it via your tablet and then use it as a remote voltage monitor. There is a peak detection feature which is a nice touch and gives the entire project a premium feel.
The serial terminal on an ESP8266 is not something new yet it is helpful in disconnecting the console window from the bench. The I2C terminal is where the device really shines as it can scan for connected devices on the connected bus. This Bus-Pirate like feature is useful for beginners as the software can scan the registers addresses of the devices as well.
[S-March] has made the schematic in PDF format as well as the entire code for the project available on GitHub so go right ahead and make it your own. We have had an ESP8266 based VT Terminal device in the past and merging the two would make for an excellent maker tool.
Thanks for the tip [René Arts]
[Jay] hacked a Blu-Ray laser diode into a keychain enclosure. He found a heavy brass keychain light from Lowe’s and stuffed the diode and a larger battery inside. The existing batteries weren’t powerful enough, so he drilled out the endcap to fit a 200mAh 3.6v lithium battery inside. He also modded the power button to only momentarily turn on the diode. With the larger battery, the laser can run for about an hour between charges. In addition to a Blu-Ray lasers, he also has versions with a 200mW red diode.
Related: Laser projector zippo
With a user interface consisting of two buttons and a three digit display, the GPS finder guides the user back to a saved location. Nine locations can be saved for navigation recall. Press a button to save location and press another button to recall. Each switch has a secondary function, for management purposes such as memory indexes and power features. An AarLogic GPS 3A module and AVR microcontroller make up the guts. With the popularity of Geocaching, this would make an impressive trinket; Leading the hunter to an undocumented treasure.
The Coby DP-151sx Digital picture frame keychain seems to be ripe for hacking. At roughly $9, you get a screen, and Li-Ion battery. That’s not bad considering a similar screen alone would cost $20 elsewhere even though it runs on a slower serial connection. While they’ve only put a 3 color pattern on it so far, more can’t be far behind. If you don’t feel like actually tearing it apart, there are some projects that have managed to customize what it displays via the USB connection.