ggtag
is an e-paper tag that can be programmed with sound using the ggwave library.
It is based on the RP2040 microcontroller and has 3.52" e-paper display.
Additionally, ggtag supports USB serial programming and allows emulation of 125kHz RFID tags (ASK and FSK).
The GGtag's CrowdSupply campaign has started, you can order one here!
Some example tags:
Both firmware and hardware are open source and licensed under the GPLv3 license. The PCB is made by Eurolan, you can find more details about the hardware design in the hardware directory.
ggtag
can be programmed either with sound or with USB serial.
To program with sound, you need to put a CR2032 battery in the battery holder and flip the switch to the BATT
position.
To program with USB serial, you need to connect ggtag
to a USB host and flip the switch to the USB
position.
Both programming modes are supported in the web interface hosted at ggtag.io, all you need is a modern HTML browser.
Here is a demonstration of how programming with sound works. Initially, three ggtags are listening and then programmed simultaneously using mobile phone.
After the initial programming, you need to press the button on the side for ggtag to start listening again. At the end make sure to flip the switch back to USB
position in order to preserve the battery.
ggtag-sound.mp4
The web interface is using Web Serial API for USB serial programming, so you need a web browser (e.g. Chrome, Edge) which supports this API. Mobile Chrome running on Android is also supported. Here is a demo of using Pixel5 phone for USB serial programming:
ggtag-usb.mp4
You can emulate 125kHz RFID tags with ggtag. This is accomplished with an ATtiny85 MCU and the avrfid firmware. When ggtag receives an RFID command, it generates the corresponding avrfid firmware and programs the ATtiny85 with it. Demo with Flipper Zero:
ggtag-rfid-flipper.mp4
Another demo with USB RFID reader:
ggtag-rfid-reader.mp4
There is a web audio receiver which implements the ggtag protocol running at https://ggtag.io/recv/. This could be useful if you want to hack on the protocol and debug stuff directly in the browser.
webrecv-demo.mp4
There is a ggtag
python package which can be used together with pyserial
or ggwave
to program the device. See the examples folder for more details.
- If you switch off the battery after successful sound programming, you need to make ~5sec pause before switching it on again.
- With some RFID readers you need to keep
ggtag
at 1cm distance for read to be successful. - If you want to display non-ASCII text, you need to convert it to image first.
- ggwave (MIT license)
- microphone-library-for-pico (Apache 2.0 license)
- Pico_ePaper_Code (GPLv3 license)
- QR-Code-generator (MIT license)
- Serial API Polyfill (Apache 2.0 license)
- avrfid (BSD license)
- stb_truetype (MIT license)
- Font Awesome (CC BY 3.0 license)
The codebase is structured in the following way:
target
- contains device only source codeshared
- contains shared source code between the device and the host libraryhost
- contains the host librarydocs
- contains the web interfacepython
- contains Python bindings for the host libraryexamples
- contains some exampleshardware
- contains hardware design files
Follow these steps to build the RP2040 firmware:
git clone https://github.com/raspberrypi/pico-sdk
cd pico-sdk
git submodule init
git submodule update
cd ..
git clone https://github.com/raspberrypi/pico-extras
cd pico-extras
git submodule init
git submodule update
cd ..
export PICO_SDK_PATH=<full_path_to_pico_sdk>
export PICO_EXTRAS_PATH=<full_path_to_pico_extras>
export PICO_TOOLCHAIN_PATH=<full_path_to_arm_toolchain>
git clone git@github.com:rgerganov/ggtag
cd ggtag
git submodule init
git submodule update
mkdir build
cd build
cmake .. -DPICO_BOARD=pico
make
The host library is compiled to WASM using Emscripten:
source <path_to_emsdk_env.sh>
CXX=emcc make
You can start a local server with make server
and access the web interface at http://localhost:8000.
There is a hosted version available at https://ggtag.io
Put ggtag into USB mode, press and hold the button and plug the USB cable.
Download the latest firmware release and copy the .uf2
file to the RPI-RP2
drive.
The tag will reboot and run the new firmware.
We'd love to hear your feedback, comments and questions about ggtag in the Project Discussions