Team:	Grupo 8: Cláudia Almeida (Coord.) , Rafael Alves , Gonçalo Peralta , Pedro Matias
Company:	Altice Labs
Supervisors:	Pedro Fonseca (Universidade de Aveiro - DETI) Hélder Tavares (Altice Labs) Nuno Balseiro (Altice Labs)

In recent years, the automation of testing processes has become a central focus across various market sectors, particularly in engineering. Motivated by this need, Altice Labs proposed the development of a product capable of interacting with the devices they produce — specifically routers and gateways — with the ability to provide feedback on their performance.

The goal of this project is to automate the process of pressing buttons, checking their operation, and determining the force required to activate them. Traditionally, button testing has been done manually, which requires the presence of a person at the test site, making remote actuation of the buttons by the automatic tests unfeasible. Manual actuation can make it difficult to perceive when the button clicks and when it does not, especially when there are many buttons to press in sequence. Pressure force appears as another variable that is difficult to measure accurately by humans, as pass/fail criteria will be subjective from person to person. Automating this operation improves precision, reproducibility, and dependability, particularly in circumstances where many buttons of various sorts and sizes must be examined. Our proposed solution fits the needs of Altice Labs and opens the door to broader industrial applications by being universally adaptable to varied devices under test (DUT).

Challenge

This project addresses the growing demand for automation in testing processes across sectors. The purpose of this project is to create a remotely controllable automaton that is capable of pressing buttons, validate their operation, measure the force required to activate them and communicate the results to the server. The solution ensures that it interacts with various types of buttons (from soft-touch buttons to hard mechanical ones) safely and reliably, while collecting detailed data on the force applied and the button’s response.

The system guarantees that force is applied consistently, yielding precise and reproducible findings, which is critical for determining if devices satisfy the required requirements. It is intended to accommodate a wide number of devices by adapting to different button sizes and mechanisms, making it applicable to a diverse range of products. The capacity to collect detailed force measurements and process information will also allow businesses to make data-driven decisions that will advise design changes, increase product reliability, and direct manufacturing adjustments.

Proposed Solution

The solution we proposed consisted of using a Raspberry Pi (RPi) as the central controller, interfacing it with a linear actuator to press the buttons and establishing an interface with a linear actuator to press the buttons and integrating a resistive force sensor to measure the force applied.
Although Solenoids are useful in applications that require quick and simple actuation, they do not have the precision required to measure force with a fine granularity. For this reason, we proposed using a linear actuator, which offers more precise control of the movement.

The process begins when the RPi sends a signal to initiate the button press. Since the RPi’s GPIO pins are limited in terms of output current, the signal will pass through an amplification circuit to effectively power the actuator. This step ensures that the actuator receives enough power to press the button without any interruptions due to signal strength limitations. When the button is pressed, the resistive force sensor integrated into the system will monitor and record the force exerted by the actuator. The system will monitor the status of the button using electrical feedback from the from the DUT to determine whether the button has been pressed successfully and whether the device has responded as expected.

Safeguards would be taken to ensure that the actuator’s force output is limited within predefined values. These precautions are crucial to prevent the actuator from applying too much force, which could result in damage to the DUT if the button becomes unresponsive or jammed. When the test is complete, the RPi will collate the test statistics, including force data and button functionality results, and transmits this information to a remote server. Finally, a packet containing the process statistics will be sent to the server and the test is concluded.

Block Diagram of the system.

Architecture

The architecture of the system consists of three main components: the Control Unit, the Control Electric Circuit, and the Mechanical Actuation.

The Control unit is managed by a Raspberry Pi that runs the control software and serves as the central processing component for the system. The Raspberry Pi generates a PWM (Pulse Width Modulation) signal to regulate the actuator’s movement, allowing for controlled button pressing with variable force. It also maintains a Secure Shell (SSH) connection with the DUT, allowing it to detect feedback from the device in real time, such as system responses or status changes upon a button click. For force measurement, the Raspberry Pi reads data from the force sensor using I2C/SPI protocols, ensuring accurate and timely data transfer from the sensor to the control software.

The Control electric circuit amplifies the PWM signal generated by the Raspberry Pi, ensuring sufficient power is supplied to the actuator. This circuit includes an H-Bridge, allowing current to flow in both directions as required to control the actuator’s movement accurately. The circuit, powered by a 12V, 3A DC power source, will provide the energy needed to drive the actuator with stability and precision, allowing for both pressing and releasing movements, required for testing various types of buttons.

Soldered printed circuit board.

The Mechanical Actuation assembly is designed to interface directly with the DUT, positioning the actuator over the buttons to be tested. This component includes a clamp that securely attaches to the DUT, providing flexibility and adaptability for different button placements and device sizes. Mounted within the clamp is a linear actuator that performs the physical pressing of the buttons, with a force sensor placed behind the actuator to capture the exact force applied during each press. This assembly connects to a PCB board, which relays signals from the force sensor back to the Control Unit, ensuring accurate control and data capture throughout the testing process.

Mechanical assembly sketch of the product.

Results

Outcome. What was achieved with the project.

This automated technology brings major advantages, including increased testing speed, greater data accuracy, and the ability to remotely control and monitor the testing process. As a result, it will improve the workflow for firms like Altice Labs, which test network gateways, routers, and other devices with physical interfaces lowering labour costs, enhancing product reliability and test more software releases in less time.

This project brought valuable technical expertise to the team gained in designing and building automated testing systems, integrating actuators and sensors with microcomputers like the 2 Raspberry Pi as well as knowledge of force measurement techniques and how to apply them in real world testing environments.