Display qrcodes on the Flipper Zero

Grab the latest qrcode.fap from Releases.

Copy the qrcode.fap file onto your Flipper Zero sd card in the apps/Tools directory. Then create a top level directory called qrcodes to store your qrcode files. This can be done using qFlipper, for example, by draging-and-dropping qrcode.fap into apps/Tools and then navigating back to the top level (where the directories like infrared and nfc live), right click, and create a new folder called qrcodes.

qrcode files are simple text files with the extension .qrcode. This app will expect them to live in a top-level directory on your sd card called qrcodes. They should have the following content:

Filetype: QRCode
Version: 0
Message: your content here

qrcode v2 supports a newer format as well (the old format still works for backward compatibility, or, if you don't need the newer features, the app will read version "0" files faster):

Filetype: QRCode
Version: 1
QRMode: B
QRVersion: 6
QRECC: L
Message: your content here
Message: multi-line content is possible

In a version "1" file, the QRMode, QRVersion, and QRECC are optional (though, must be in that order if more than one are specified). The app will attempt to use the specified mode, version, and/or ECC, if the content will fit. Otherwise, it may select a different mode, version, and/or ECC. Keep reading to learn about the meaning of QRMode, QRVersion, and QRECC.

Version "1" files also support multi-line content. Each line starting with Message: will be concatenated together with newline characters.

My recommendation is to allow the app to select a mode, version, and ECC level for you and, then, if you find that your qrcode reader prefers specific settings, update the file appropriately.

qrcodes support 4 formats called "modes": numeric, alpha-numeric, binary, and kanji. Because of the limited screen real-estate on the Flipper Zero, you'll want to pick the best mode for the data you are trying to display.

If unspecified in the .qrcode file, the app will automatically detect the best mode to use based on the message content.

Consists of only numbers, nothing else. This mode can encode the most data and is useful for things like phone numbers. To use this mode, your message must not contain non-numeric characters. For example, a message content of "(xxx) xxx-xxxx" can not use numeric mode (it would require "binary" mode, in fact). Instead, your message should just be "xxxxxxxxxx".

This mode can encode numbers, uppercase letters only, spaces, and the following symbols: $%*+-./:. This format may be appropriate for urls, as long as you're only encoding the domain name and you remember to use uppercase letters (ex: HTTP://EXAMPLE.COM). If your url includes some path after the domain, you'll likely need to use binary mode because the paths are usually case-sensitive.

A qrcode in alpha-numeric mode can encode ~40% less data than numeric mode.

This mode is a little bit of a misnomer: binary mode simply means that the message will be encoded as 8-bit bytes. The qrcode standard stipulates that text will use ISO-8859-1 (also known as Latin-1) encoding, not utf8 as would be the standard these days. However, some readers may automatically detect utf8. To be standard-compliant, that basically means you can only use Latin letters, numbers, and symbols.

Multi-line messages will always be in binary mode, since the other modes cannot encode a newline character.

A qrcode in binary mode can encode ~60% less data than numeric mode, and ~30% less than alpha-numeric.

This mode is unsupported, so I won't go into detail. A limitation of the underlying qrcode library that I'm using, unfortunately. If there's interest, perhaps I'll hack in support sometime.

A qrcode's version specifies how "big" it is. Higher versions contain more "modules" (ie, the "pixels" that make up qrcodes) and, thus, can encode more data. A version 1 qrcode contains 21x21 modules, whereas a version 11 code (the largest the Flipper Zero can display) contains 61x61 modules. The modules of a version 1 code will be 3x3 pixels on the Flipper Zero screen; version 2 and 3 qrcodes will each have 2x2 pixel modules; and version 4 through 11 qrcodes will have single pixel modules.

If unspecified in the .qrcode file, the app will automatically select the lowest version that can contain all of the message content, given the mode selected in the previous step.

A qrcode's ECC level determines the qrcode's resilience to "damage". In the case of the Flipper Zero, "damage" might be a dirty screen, dead pixels, or even screen glare. Higher ECC modes are more resilient, but can contain less data. The ECC modes are Low, Medium, Quartile, and High and can be specified in the .qrcode file using the first letter (L, M, Q, and H).

qrcode readers may have an easier time reading qrcodes with higher ECC levels, so, if unspecified in the .qrcode file, the app will select the highest ECC level that can contain all of the message content, given the qrcode mode and version selected in the previous steps.

The app is fairly straightforward. When it first starts, the file browser will automatically open to the qrcodes directory and display any .qrcode files. Select one using the arrow keys and the center button. The qrcode will display. If you push the right arrow, some stats will display: the qrcode "Version"; the ECC level; and the qrcode Mode (Numeric, Alpha-Numeric, Binary, or Kanji).

While viewing the stats, you can select Version or ECC using the up and down arrows and the center button. You can then increase or decrease the Version or ECC using up and down and save your choice using the center buttton. This feature was mostly added for my own amusement and testing, but, theoretically, it may help a reader that's having trouble if the default ECC is less than the highest value ("H"): you can increase the Version by 1 and then set the ECC to "H". Whether or not this helps depends on the reader.

You can hide the stats by pressing the left arrow.

When you're done viewing the qrcode, press the back button to return to the file browser. If you push the back button in the file browser, the app will exit.

I will ask that you temper your expectations: the Flipper Zero screen is small and many readers may have difficulty reading the qrcodes, especially if they are encoding a lot of data. However, I have successfully got my iPhone to read qrcodes encoding phone numbers, wifi info, and a url, all the way up to a version 11 qrcode (ie, the largest size the screen will fit).

Most phones can automatically connect to wifi networks from a qrcode. If you should like to encode your wifi's connection info into a qrcode, here's how you'd do it:

Filetype: QRCode
Version: 0
Message: WIFI:S:<ssid>;P:<password>;T:<encryption>;

Replace <ssid> with the name of your wifi, <password> with the password. <encryption> would be "WPA" or "WEP". If your wifi is open (no password), this can be "None" and you can remove P:<password>; from the message. If your wifi is hidden (ie, does not broadcast the ssid), you can add H:true; to the end.

Note that if your ssid or password contain any of these characters: \";,:, you'll need to "escape" it by placing a backslash (\) before it.

For example, if my ssid was "wifiball" and not broadcast, and the password was "pa$$:word" with WPA encryption, the message would be:

Message: WIFI:S:wifiball;P:pa$$\:word;T:WPA;H:true;

Phones can scan vCard qrcodes to automatically add a contact to their address book. Starting with qrcode v2, multi-line qrcodes can be created, allowing you to create vCards!

Filetype: QRCode
Version: 1
Message: BEGIN:VCARD
Message: VERSION:3.0
Message: N:Smith;John
Message: FN:John Smith
Message: ADR;TYPE=dom,home,postal,parcel:;;123 Example St;Exampleton;CA;90210;
Message: BDAY:1970-01-01
Message: TEL;TYPE=pref,voice,msg,cell:+18005551212
Message: END:VCARD

Check the vCard specification to learn about all of the fields and their values.

First, clone the flipperzero-firmware repo and then clone this repo in the applications_user directory:

git clone [email protected]:flipperdevices/flipperzero-firmware.git
cd flipperzero-firmware/applications_user
git clone [email protected]:bmatcuk/flipperzero-qrcode.git

Next, in the base of the flipperzero-firmware directory, run fbt:

./fbt fap_qrcode

This will automatically install dependencies and build the application. When it has finished building, the .fap will be in build/f7-firmware-D/.extapps/qrcode.fap (fbt output will tell you where to find the .fap, should it change in the future).

This application uses the QRCode library by ricmoo. This is the same library that is in the lib directory of the flipper-firmware repo (which was originally included for a now-removed demo app), but modified slightly to fix some compiler errors and allow the explicit selection of the qrcode mode.