The design of our ramp was done with factors of consistency and degrees of freedom in mind. We wanted our user to be able to use the ramp with ease and the motion of the ball should be largely consistent. Additionally, to add variation into our game, our ramp had to have sufficient degrees of freedom to make the game more exciting, challenging and enjoyable.

Weeks 1-3

Component: Launcher

Idea: We considered making our own projectile launcher, however, it was too rudimentary and lacked consistency. To ensure the consistency, accuracy and power of launching the ball, we intended to purchase a spring loaded projectile ball launcher from online 030suppliers.

Did it work out? No. Many online suppliers lacked details about their launchers, such as the initial velocity of the ball and the force of launching. The lack of information led to a lot of uncertainty in the movement of the ball and how far it would land, hindering our calculations and making it tough for us to predict the actual movement of the ball.

In the end … we settled for rolling the ball down the ramp instead. This would make our calculations simpler, facilitate the construction of the mechanism and ensure the consistency of results (i.e. the ball will always land in the box).

Weeks 4-5

Component: Ramp

Idea: We wanted to allow the user to vary the height at which the ramp was placed, hence we decided to mount the ramp on a jack with 5 notches of adjustable height, similar to that of a gym chair. The ramp was thus attached to the jack and pivoted at the top of the box, allowing room for movement. Furthermore, we designed the ramp with 5 lanes, akin to a swimming pool. This allows the user to roll the ball down at different points along the side of the box so that more variations in notes may be achieved.

Did it work out? The idea was feasible, however it did restrict the user in having limited degrees of freedom, since the ball may only be rolled down 5 different heights and along 5 different points along the side of the box. This limits our musical box in its capability as an educational tool.

In the end … we decided to look for further ideas which allowed us to achieve more degrees of freedom and in maximising the potential of the box.

Weeks 6-7

Component: Ramp

Idea: In order to increase the degrees of freedom of rotation for the ramp, we added in more hinges and pivots. A hinge would allow the user to vary the angle theta of the ramp to the horizontal while a pivot would allow the user to swivel the ramp about a certain point, hence varying the angle phi. Protractors were also mounted to the ramp to allow users to measure the angles theta and phi. Additionally, we included rails along all 4 sides of the box so that the ramp can be moved along any side of the box (elaborated below).

Did it work out? Yes! The degrees of freedom for the ramp increased, from 1 rotational axis (1 degree of freedom) to 2 rotational axis and 1 translational axis (3 degrees of freedom. This maximises the potential for the box to be used as an educational tool and allowing all 5 sides of the box to be hit. Furthermore, the inclusion of protractors allow users to carefully calibrate the ramp to their liking.

In the end … we finalised our design for the ramp mechanism.

Component: Metal Cage

Idea: We wanted to construct a metal cage using aluminium profiles to house the entire box structure, as well as provide a means for the ramp to slide along to enable lateral movement. The cage would also allow us to transport and handle the box easily and replace tinted covers to cover up the wiring conveniently.

Did it work out? Yes. We made use of existing aluminium profiles, sliders, screws and nuts available in the lab to test out our idea. The metal cage also had 4 additional legs at the bottom to prop the whole acrylic box up. This was to provide space for the wires and PCB attached to the base of the box.

In the end … our metal cage not only served as a sliding mechanism for us to position our ramp, it also allowed our whole set-up to be more compact.

Final Product

The workings of our final ramp design can be seen in the video below.