Blog 6

Hello everyone! Welcome back to my learning journey! Today I will be covering the shooting and loading mechanism of my group's ping pong ball launcher and my experience making a game involving a marble ball with cardboard in practical 4.

Operating Principle and Mechanism Design

When my lecturer mentioned that the topic of the lesson was Mechanism Design and Operating Principle, I had a rough idea of what we would be learning for the Mechanism Design part, but when it came to Operating Principle, I was completely lost. Firstly, I learnt about what Operating Principle meant, and how it was applicable in my everyday life. Operating Principle, basically meant the theory which makes things work the way they do. For example, most devices are designed based on principles that are either mechanical, electrical or chemical, such as in car or smartphones, electrical principles are used to make them work.

Next, we went through the concept of Mechanism Design. Mechanism refers to something that transforms forces and movement into a desired set of output forces and movement. I roughly knew what a mechanism was and what it meant, and so learning this was not too difficult for me. The main 6 mechanisms that we would have to know to use in functioning prototypes were:

Actuators
Cams
Gears
Levers
Ratchets
Springs

Even with knowing what some of these mechanisms were, I still did not know what some of them were, such as actuators and cams.

Next, our group was tasked with coming up with a shooting and load mechanism for an original design for a ping pong ball shooter. After discussing for a while, our group came up with the following design:

For the propulsion: Spring can be used to to store energy and propel the ping-pong ball. Users will pull back the handle until it lays behind the trigger of the launcher. This also compresses the spring and stores energy which will all be released and shoot the ping-pong ball out once the trigger is pressed.

Propulsion Principle

The launcher uses a spring as the energy storage mechanism to propel the ping pong ball. User will have to manually pull back the handle that is connected to the spring to compress the spring. The trigger will then hold the compressed spring in place. When the trigger is pulled, it will lay flat with the barrel which will allow the spring to release and propel the ping pong ball out.

There is a rubber flap at the end of the barrel also. This is to prevent the balls from falling out. Since the rubber flap is flexible, when the ping pong ball is propel out, the force of it will be enough for one end of the flap to bend and give way for the ball to exit. The rubber flap will then bend back again after the ball exits.

Ball Loading

There is a compressed spring at the end of the magazine. It is kept compressed by the weight of the ping pong ball. As the balls propel outwards, the weight decreases which means the spring can unwind more. This means that the ping pong ball will automatically be pushed upward by the spring at the bottom after one ball gets propelled out.

Practical 4

Now moving on to Practical 4 where I had to design a game involving a marble ball using cardboard with my group members.

Practical 4 was titled "Game Design with Cardboard", and when I saw that title, I knew that it would be extremely fun. The previous practical involving cardboard, Practical 2, was an absolute blast to carry out, as my team and I were able to coordinate incredibly well to create a cardboard model that looked absolutely great! Practical 4 was actually quite similar to Practical 2 in a way, as we would still be required to create some sort of cardboard model, but this time, it would have to be a functional "game" that would allow a marble to remain in constant motion for at least 30 seconds, all while making use of several of the mechanisms that we learnt during our lesson on mechanisms!

Before the start of the practical my group had a small discussion online on the game we were going to make and after some deliberation, we had decided on making a cardboard version of pinball machine

This was the design we were aiming for:

How this pinball machine works is that there will be 2 flippers that pushes the marble up. To control the flippers, there will be a PUSH button for each flippers. To apply the spring mechanism, rubberbands were used as it is elastic and it will go back to its original state after being stretched.

Below are some photos taken during the practical.

However, the practical was not always smooth sailing. As when we had finished our design and was testing it, we realised that the spring mechanism was not strong enough to push the ball to continue the game. As such, we had to come up with a separate design to make the requirement.

Thankfully, Joel, my group member realised that we can substitute the flippers with a lever instead. A lever can produce more power and it will be able to push the marble up by controlling it manually. Without further ado, we began to install a lever on our design.

Our New Design: