The individual piece elements were designed with production time, cost and ease of repairability in mind. Initially we had no requirements for this component of the project since we were only using the standalone piezo sensors as the individual elements themselves. However, along the way, as the design of the box evolved, the key element design had to follow suit as well.

We had to consider the fact that since we wanted a 5x5x5 arrangement, there would be a total of 125 individual key elements. It would be best to find a method that takes the shortest time to manufacture since we cannot have a box with missing pieces. In addition, since we had to outsource the acrylic pieces, cost was a major factor. There might also be a chance that over time, the piezo sensors may no longer be functioning. As such, we had to ensure that our layout enabled repairability.

Weeks 1-3

Component: Piezo Sensor Disks

Idea: Our very first iteration of the key elements involved just the piezo sensor itself as at that time, the box was designed with circular holes to house the circular piezo sensor disks, with the intention that the ball will bounce directly onto it.

Did it work out? However, the piezo sensors were tiny and in order to comfortably fit them into the 12 inch acrylic box, there needed to be many of those, which affected the cost as well as complexity of the project. Furthermore, there was a high chance that the piezo sensors might be loosened in place due to direct contact of the ball with the sensors.

In the end … taking all these factors into consideration, as well as the evolving design of our box, we needed to come up with a more durable and achievable alternative.

Weeks 4-5

Component: Acrylic Keys

Idea: To protect the piezo sensors which might potentially be ruined from the impact of the ball, we wanted to overlay pieces of acrylic over it. We opted for a configuration similar to that of keys in a keyboard so that the ball could bounce upon contact with the acrylic pieces.

Did it work out? Upon experimentation, we found that having one spring per acrylic piece made the bouncing surface unstable. This impacted the way the ball bounced and greatly reduced its ability to rebound.

In the end … we devised other ideas which had a lesser impact on the rebound of the ball.

Weeks 8-9

Component: Individual key element

Idea: As an alternative to our acrylic pieces, we looked to 3D printing small “tables”. These table legs would be attached to thin adhesives, which would subsequently be stuck to the inner sides of the acrylic box. Additionally, they would also have a middle piece where the piezo sensor would be stuck on.

 

 

 

Did it work out? Yes! We found that 3D printing these tables were a good alternative. They were not only cheaper and more time-efficient as we could utilise existing resources in the lab, they also had minimal performance differences compared to the acrylic pieces upon experimentation.

In the end … we settled for printing our key elements in different colours to demarcate different points systems for different concentric circles.

Final Product

Our final design for the key elements can be shown below.