As it turns out, a Maker by the name of Josh is working on a similar offline password keeper, albeit with an ATmega32U2 instead of the 32U4.
Like the Mooltipass, the USBPass is connected to a computer via USB and read as an HID keyboard. Aside from the ATmega32U2, the platform is equipped with a minimal amount of components, including a USB connector, three buttons and a few passives chips.
“A total of 20 passwords can be stored in the microcontroller’s memory, which can be ‘typed’ by the platform using the push buttons,” explained HackADay’s Mathieu Stephan.
On the software side, the USBPass firmware is based around the LUFA USB stack, to which Josh added HID report functionality to facilitate data transfer from his desktop application.
“The latter uses the Linux/Windows/OS X HID API library so bringing his software to other operating systems can be done in no time,” Stephan added.
Although the current version of the USBPass is pretty sweet indeed, Josh says he is working on a second iteration of the platform which will likely boast an OLED screen.