qr_transfer

This library creates a sequence of CRC and serial checked QR code sequence in order to transfer a small file (a few KB) and is able to decode the sequence of files

Files include:

requirements.txt - Requirement file for virtual environment make_random.py - Creates a random file of length 1300 bytes for testing input_file.txt - A file created by make_random.py make_qr.py - A program that makes a sequence of QR code png files from a binary file read_qr.py - A program that reads, checks a sequence of QR png or jpg/jpeg files with QR codes to create an output file

Environment

Tested on python 3.11

Help

Running each file without parameters will show a usage help line

Installation

• On Ubuntu or MacOS:

pip -m venv venv pip install -r requirements.txt

• On PC/ Windows Don't know

Testing

Run the following line to encode:

python3 make_qr.py input_file.txt output_qr 512

Output should be:

Creating output_qr_0.png Creating output_qr_1.png Creating output_qr_2.png

Run the following line to decode:

python3 read_qr.py output_qr png output_file.txt

Output should be:

reading output_qr_0.png reading output_qr_1.png reading output_qr_2.png reading output_qr_3.png [ WARN:0@0.278] global loadsave.cpp:248 findDecoder imread_('output_qr_3.png'): can't open/read file: check file path/integrity not found

(Ignore the last error, it is always there since the program is trying to read a non-existent file)

Compare the input to output files:

diff input_file.txt output_file.txt

Output should be empty

Comments

• Up to 255 QR files are supported
• File order makes a difference! When downloading files make sure to label them xyz_0.jpeg, xyz_1.jpeg, etc. based on the order of creation
• Both file order and checksums are checked and if there is any error, the read_qr.py program will report this error. There is no overall checksum, so if the number of files transferred was incorrect, the program will not know this.
• iPhone camera only works up to 512 bytes/QR image
• Exceeding this number may cause QR codes to be transferred incorrectly
• PNG codes work up to 967 bytes
• This entire code was coded swiftly (~2 hours) and testing was scarce. Proceed with caution
• All testing was done with Python 3.11 on Mac OS