Python-Based Modem Communication Library Project

Technical Details

Project Requirements

• Develop a Python library for communicating with a modem, capable of sending AT commands and processing responses.
  • Extra: Automatic detection of the modem serial port.
  • Extra: Customization of serial port settings like baud rate and parity.
• Write sample code to send HTTP GET and POST requests to webhook.site via the modem, using the previously developed library.
• Create example code to send and receive MQTT messages on a topic via a free and open MQTT broker hivemq, using the library.
• Enable Raspberry Pi to access the internet through the modem using:
  • PPP protocol
  • QMI/RMNET protocol
  • ECM protocol
• Measure the speed of connections established through these three protocols and compare them.

Technologies and Methods Used

• Python: Used as the development language in the project.
• AT Commands: Utilized for communication with the modem.
• Serial Library: Employed for serial communication between devices.
• HTTP (Hypertext Transfer Protocol): The basic web protocol used for data exchange.
• MQTT (Message Queuing Telemetry Transport): A lightweight and simple messaging protocol.
• PPP (Point-to-Point Protocol): A protocol used for establishing a point-to-point connection over the internet.
• QMI (Qualcomm MSM Interface): Used in mobile devices and data cards for 3G and 4G LTE connections.
• ECM (Ethernet Control Model): A protocol for sending control signals over Ethernet.

System Architecture

• ModemCommunicator Class: The class used for communicating with the modem.
• Examples of communication over HTTP and MQTT protocols.
• Establishing internet connection on Raspberry Pi using various network protocols.

Development Process

• Stage 1: Development of the basic library for communication with the modem.
• Stage 2: Addition of functions to the library for sending and receiving data using the HTTP protocol and the development of an example application that facilitates communication through these functions.
• Stage 3: Incorporation of functions into the library for publishing and subscribing to messages using the MQTT protocol and the development of an example application that communicates through these functions.
• Stage 4: Establishing internet connection using PPP, QMI, and ECM protocols, conducting speed tests, and comparing the protocols.