Created by Thibault Brevet, CONSTI2GO is a portable device that allows, on the press of a button, to print copies of the US Constitution by hijacking the existing network of standard receipt printers.
Thibault first prototyped the electronics with an Arduino and achieved communication with the printer over serial interface via a standard language called ESC/P. The Arduino talks to the printer through a MAX232 chip to convert the TTL signal to RS-232 levels (visible with caps directly soldered directly to it in the pictures). Storing the full text was an issue with the Arduino because it required about 45k of memory, Thibault explains. He ended up using a Teensy 3.1 as it has plenty, running the same code. The whole thing is autonomously powered by a li-po battery, including a little usb li-po charger. Since the li-po only provides 3.7V the max232 was changed to the max3232 which provides operation from 3.3V and up.