Difference between revisions of "F18: Hit the Balloon"

Revision as of 21:30, 19 December 2018

Hit the Balloon

Abstract

The objective of our project is to implement a game called "Hit the Balloon." Hit the Balloon is a game that has balloons that randomly spawns from the bottom of the screen to the top. There is a bow and arrow that moves vertically on the left side of the display. The player is able to control the vertical movement of the bow and shoot arrows at the balloons that are moving upward. When the arrow hits the balloons, the balloon object will be a hit. The objective of the game is to hit the maximum number of balloons with a limited number of arrows and time. At the end of the game, it will display the score, number of balloons the player hits. A screenshot of the "Hit the ballon" game that will be emulated is shown in Figure X.

Figure X: Example of Hit the Balloon Game

Objectives & Introduction

Team Members & Responsibilities

• Aaron Lee
  • Arrow object(display, shoot, movement), testing, packaging, and report
• Rahul Kadam
  • PCB, start/end screen, scoreboard, acceleration sensor, and testing
• Vijay Vanapalli
  • Balloons, hit detection, and testing

Schedule

Parts List & Cost

PCB Build of Materials

Design & Implementation

The design section can go over your hardware and software design. Organize this section using sub-sections that go over your design and implementation.

Hardware Design

Discuss your hardware design here. Show detailed schematics, and the interface here.

This project consists of using the SJOne microcontroller, 16x32 RGB LED display, and our custom PCB, used to power the microcontroller and the LED display. The system design of this project is shown below in Figure X.

Figure X: Hit the Balloon System Design

The first step after receiving all of the hardware was understanding how the RGB LED Matrix worked by reviewing AdaFruit's documentation [5], SparkFun's documentation [6], and watched a few youtube tutorials [7] to get the RGB LED Matrix and the SJOne microcontroller properly connected.

The connections for the RGB LED Matrix consist of six data pins (R1, G1, B1, R2, G2, B2), three control pins (CLK, Output Enable, Latch), three row-select pins (A, B, C), and four GND pins. The 5V/2A power supply connects to the backside of the LED matrix board. The ribbon cable that came with the Adafruit LED matrix was attached to the 'INPUT' connection on the backside of the LED matrix and the following connections were made to the SJOne microcontroller's GPIO pins using male-to-female wires. Please note that the ground connections from the SJOne board was connected to the ground of the LED Matrix and the power supply as shown in Figure X. The SJOne microcontroller is also supplied power through USB or an external source.

Figure X: SJOne Microcontroller Connection to LED Matrix

If these connections are properly connected, the LED matrix should be on with the LEDs of random rows flashing. To test the LED Display, the AdaFruit Arduino library was used as a reference to port over the displaying of a design.

Hardware Interface

To begin this project, understanding the various pins on the input of the 16x32 RGB LED Matrix display is important in knowing how the display gets updated. The 16 and 32 indicate that the display has a total of 16 and 32 rows and columns, respectively. As mentioned above, there are 3 pins for row selection (A, B, C), 6 data pins (R1, G1, B1, R2, G2, B2), and 3 control pins (LAT, OE, and CLK).

The 16x32 display is divided into two sections as shown in Figure X, which is why the microcontroller needs to drive the top and bottom section of the display at the same time.

Figure X: 16x32 LED Display Diagram

To update the display, the output enable pin must be cleared. Then, on the rising edge of the clock, you can update a 32-bit shift register that is used to store data. Each corresponding bit [0:31] corresponds to the column on the display. Depending on if the bit is set in this register, will determine if you want that column of the LED to light up. When this register is updated, then you can toggle the clock bit.

After connecting the display with the SJOne board, you should see bright LEDs lighting up different rows as shown in Figure X. After seeing this display, when you press on the wire to the input of the LED matrix, you will notice the LEDs on different rows will begin to flicker.

Figure X: 16x32 LED Display Diagram

Now that the board is powered up, we utilized Adafruit's display library ported the Arduino code to the SJOne LPC17XX microcontroller.

The first objective was to display a static screen, such as the start screen, on the display to learn how to manipulate the LEDs on the 16x32 matrix. A 16x32 two-dimensional array was created to indicate the color of a particular LED located on the matrix display.

Figure X: Static Start Screen

Following are the list of colors that are attainable by the LED

Figure X: LED color List for reference

Software Design

The following diagram elaborates on the flow chart that each task follows. The project is designed primarily on tasks handling different modules of the project viz, Balloon movements, level selector, hit detection and so on. The main two types of objects are arrows and balloons although by default they are of the same object type and simply have different parameter declarations. The input for the system includes the movements picked up by the onboard acceleration sensor and the button press from the player.Scores are kept throughout the session of the game and are updated accordingly.

Figure X: Example of Hit the Balloon Game

Three tasks were created with same priority for the game design.

• In Task 3: This contains the actual game design i.e Start Screen, Game Screen, End Screen and Level Screen. Where, End Screen and Game Screen show scores : Game Screen updates the score live on hit, whereas the End Screen simply shows the players final score.
• In Task 2: This task is in the suspended state till the user selects a level as two. This is where the difficulty of the game increases, where 2 balloons are generated randomly - thus making it difficult for the user to aim or to score.
• In Task 3: This task is where the arrow object is being generated and controlled using the switch and acceleration sensor, where switch is used to shoot the arrow and the acceleration sensor move the arrow up and down. The important task in Task 1 is the hit detection, where we are continuously monitoring the arrow's row and column and balloon's row and column - upon which the decision is made and the score is updated.

RGB LED Matrix

The API detailed in the following flowchart, is a function that is committed towards generating the center of the object and holding its respective dimensions. Another function called display Object is tasked with drawing the object on the LED matrix.

Below is a snippet of printing out the shape of the balloon, keeping its dimensions in mind. Essentially the display is updated with the object after iterating through each pixel in the matrix, with the exception of the specified boundaries of the object in question

Figure X: Snippet of code, showing how the balloon is iterated through

The challenging part of the moving object design was to ensure how the object was to be shown drifting downward or upward in a smooth way. By design the LED Matrix sets color in sets of 8 rows as can be deciphered from the attached code snippet. More of the problem and how it was tackled is elaborated in the Testing.

Implementation

All the functions used are enlisted in the following class. Moreover, these are to be considered with the tasks in main that are dedicated towards the different background screens of the game itself from Start to the Final Score screen.

The game consists of a single player navigating through different levels (currently implemented two levels with varying number of balloons).

PCB Design

The Printed Circuit Board design was done using Eagle PCB editor which was a free open-source software for students. The software design tool enables designers to seamlessly connect schematic diagrams, component placement, PCB routing, comprehensive library content. Following components are added while designing the PCB -

• 34 pin female header to connect the SJONE board.
• 16 pin male header for the 16x32 RGB matrix.
• 8 pin male header to connect the external switch to the SJONE board & extra ground and vcc pin
• 2 pin power connector
• 100 ohm resistor

PCB design Issue

It is difficult to design a PCB without having components in hand because we are not able to set the exact drill size and component spacing. It was difficult to tune in our components because we were using EAGLE PCB autorouter to create traces and if the component orientation,placement and organisation is not proper the autorouter will not create 100% trace for you and then we have to manually create traces, in best case scenarios the autorouter can create vias between two connections.

Figure X: PCB Layout

Testing & Technical Challenges

Describe the challenges of your project. What advise would you give yourself or someone else if your project can be started from scratch again? Make a smooth transition to testing section and described what it took to test your project.

Testing

For testing this project, each group member had their own individual setup consisting of LED Matrix display, SJOne Board, and development environment. Our approach to developing and designing this game was to by making everything modular, where each person is given an object/feature to implement.

When we began the project and tested our code, it was easy to maintain because we started from scratch and didn't have a lot of code to control between the three of us. However, as we started adding more features into the game, the code began to get messier because we started to add sections from one person's code into another. Essentially, when one thing that works without a lot of tasks will work flawlessyly, but when we integrated different objects and features together, we started to face some of the following issues.

Implementing multiple objects caused display to flicker/dimness in objects

Originally, our problem with this issue started when we had two objects in one task, the arrow and shooting arrow. To fix this issue, we separated these objects into multiple tasks. By doing this, we were able to make the display fluid and we were able to solve this issue between these two objects.

However, as the game design began getting more complex by introducing more objects with different logic (balloons, hit detection, scoreboard, and the start/end screen), we began to notice that the display flickering issue came back. We tried several methods to try and reduce/eliminate

Rather than having two objects in one task, the objects were separated into their own task. As a result, we have one task displaying the arrow object that is fixed on the left side and another task that displays the arrow that is shot across the screen.

2. Balloon object that is created and moving down the display is displaying a very faint color.

• Solution:

Conclusion

Conclude your project here. You can recap your testing and problems. You should address the "so what" part here to indicate what you ultimately learnt from this project. How has this project increased your knowledge?

Project Video

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Project Source Code

• Sourceforge Source Code Link

References

Acknowledgement

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References Used

List any references used in project.

Appendix

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