RFID emulator + E-paper badge can be programmed with sound

In a way, an e-paper screen is a great base for a reprogrammable RFID card. The display only needs power during a refresh, and 125 kHz RFID tags are passive in the sense that the power for the RFID transaction comes from the reader itself. [Georgi Gerganov] put them together in the GGtag, an open source project for a 3.52″ electronic paper tag with a trick or two up its sleeve.

A clever feature is that it's programmable with sound, a feature built from another [Georgi] project called ggwave, a data-to framework -sound (and vice-versa) which has been ported to just about every hardware platform imaginable, including mobile phones, and can reliably send data over the air.

Sound data transmission is rate limited but has a number of advantages, the most important of which is the wide range of compatible devices. There is a web tool to program GGtag with sound available at ggtag.io that will give you a preview and let you hear how it works. The data encoding method gives transmissions a charming beep-boop quality that is somewhat reminiscent of an analog modem's handshake. GGtag can also be programmed via serial USB, a faster (but slightly less exciting) option.

The project's GitHub repository contains code and technical details for GGtag, and the CrowdSupply project is in the works for anyone who would prefer to purchase one once they become available.