[Vídeo do projeto]

Team: Group 01:
Gustavo Vieira , João Sousa , Mariana Castro , Maurício Benga , Miguel Azevedo
Company: Azevedos Indústria - Máquinas e Equipamentos Industriais SA
Supervisors: Ernesto Martins (DETI)
João Peixoto (Azevedos Indústria - Máquinas e Equipamentos Industriais SA)

This project aims to develop a portable system capable of monitoring continuosly the relative humidity of cork during its production, generating calibration curves and exporting said curves to production machines, while also having a graphical user interface to interect with it all. The solution achieved revolves around one key sensor, the P78 industrial transducer, capable of measuring the electrical permittivity from materials and, from there, derive its relative humidity.

Challenge

Cork is a natural resource that presents high industrial relevance, due to its thermal, acoustic, mechanical and environmental properties. The relative humidy of the cork granules is a critical variable along the production process of cork, since if the humidity value were not to be moderated (between 5 e 8 %), the quality of the final product is compromised. Today, this parameter is monitorized in a descrete way (every 45 minutes), resorting to external sensors to production machines.

The challenge of this project is to develop a system that can tackle this problem, while also having the following requirements:

  • Derive the relative humidity of the cork granules from its electrical permittivity
  • Generate calibration curves based on data introduced by the user.
  • Export the generated calibration curves to the production machines.
  • Integrate the P78 sensor, establishing communication between a microcontroller via the RS-485 protocol.
  • Develop a power system capable of guarantee an autonomy of 1-2 hours and charging via USB-C.
  • Implement a user interface and integrate it with a display.

Proposed challenge, initial specifications, requirements, constraints, …

Solution

The developed solution can be described in three main parts: The general architecture, the hardware and the software. Each of these topics will be described in more detalied in the next sections.

General architecture

The system’s architecture is composed by different hardware modules, all connected as ilustrated in the block diagram below:

Markdown

The P78 sensor will communicate with the Raspberry Pi 4 microcontroller through the RS-485 to USB converter. This arrangement ensures the requirement of communication between the P78 sensor and the microcontroller via the RS-485 protocol.

By programming the Raspberry Pi, this microcontroller will derive the relative humidity of the cork granules, generating calibration curves and export the generated calibration curves to the production machines.

Furthermore, a display communicating with the Raspberry Pi in order to support the interactivity between the user and the system via a user interface developed in software.

There’s also a power subsystem, containing the battery, the BMS module, the USB-C breakout board, the voltage regulator, the buck converter and the boost converter. This one is responsible for ensuring the whole system’s autonomy and charging capabilites, as well as to support its portability.

All this hardware modules are housed in a 3D printed enclosure, shown below:

This enclosure is composed by a top division and a bottom division.

The developed hardware system resides in the top division. Ventilation louvers surround the encolusure on its sides and on its back, to serve as an extra layer of overheating protection. A door is placed at the front of the top division to enable access to its hardware everytime it is needed when open and to ensure more robustness and protection of the hardware when closed. There is also one extra opening on each side and on top, which enables the connection of external devices/machines when needed.

The bottom division is purposed for a shelf. This shelf can be filled with the cork granules whose relative humidity is desired to be determined. The shelf can be taken off, for ease of use, and put back in again for new cork granules measurements, making it a practical approach for the user.

Between the top and bottom division, there is a circular opening, which enables to sensor to set in place on the top division while taking measurements of the eletrical permittivity of the cork granules situated below, inside the shelf.

This enclosure is crucial to ensure the ease of use and the portability of the system.

Hardware implementation

Software implementation

Results

At the end of this prokect, we were able to make a viable solution for the proposed problem, with a graphical interface for real-time visualization and interaction with the user.

More information

All other information to help understand the project and the team’s achievements: photos of the system under construction, diagrams, tests, …

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Extra: Including images and tables

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How to include images and tables

Images and tables can be included using Markdown or HTML.

Markdown

The “markdown” language has specific commands to include figures and tables, which are simpler than the corresponding HTML codes. The code to include an image is as follows:

Alternative text

To simplify, the image is placed in the same folder as the project template. If it is necessary to define the size of the image, the following example can be used [^note]: [^note]: Not all Markdown interpreters support this formatting.

Alternative text

For tables, the structure is as follows:

Header One Header Two
Item One Item Two
Another item And another one

HTML

As an alternative to Markdown syntax, it is always possible to use HTML (“Hyper-Text Markup Language”). Although more complex, it is also safer when it is necessary to manipulate the elements you want to present. For example, changing the size of an image (not all Markdown interpreters support the formatting indicated above) or defining the formatting of a table (background color, width and type of lines, …)

Alternative text

For tables as well:

Table caption
Header One Header Two
Item one Item Two
Another Item And another one
Two columns