IoT:
        Node-RED: A flow-based development tool for visual programming that can be used for wiring together IoT devices.
        Eclipse IoT: A set of open-source projects that provide the building blocks for IoT solutions, including MQTT-based communication.

    Barcode:
        ZBar: An open-source software suite for reading barcodes from various sources, such as image files or webcam.
        Libdecodeqr: A C/C++ library for decoding QR codes from image files.

    RFID:
        RFIDIOt: An open-source python library for working with RFID readers.
        MFRC522: A popular RFID reader/writer module used with Arduino, and there are various open-source libraries available for it.

    Printers:
        ESC/POS-Print-Kit: A JavaScript library for controlling POS (Point of Sale) printers.
        CUPS (Common Unix Printing System): A modular printing system that allows a computer to act as a print server.

    QR Codes:
        ZXing (Zebra Crossing): A multi-format 1D/2D barcode image processing library that can be used to decode QR codes.
        Qreator: An open-source QR code generator for Linux.

    Integrated Solutions:
        OpenBoxes: An open-source supply chain management and inventory control system that supports barcode scanning and RFID.
        Traccar: An open-source GPS tracking platform that can be extended to support IoT tracking.