S16: Expendables

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Revision as of 02:26, 21 April 2016 by Proj user3 (talk | contribs) (Hardware Interface)

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Grading Criteria

  • How well is Software & Hardware Design described?
  • How well can this report be used to reproduce this project?
  • Code Quality
  • Overall Report Quality:
    • Software Block Diagrams
    • Hardware Block Diagrams
      Schematic Quality
    • Quality of technical challenges and solutions adopted.

Project Title

Abstract

This section should be a couple lines to describe what your project does.

Objectives & Introduction

Show list of your objectives. This section includes the high level details of your project. You can write about the various sensors or peripherals you used to get your project completed.

Team Members & Responsibilities

Schedule

Sl. No Start Date End Date Task Status Actual Completion Date
1 3/07/2016 3/13/2016 Components buying Completed 3/18/2016
2 3/14/2016 3/20/2016 LED panels study Ongoing
3 3/28/2016 4/03/2016 Raspberry Pi 3 study
4 4/04/2016 4/10/2016 Pixel Driver Design
5 4/11/2016 4/17/2016 PCB Design Completed 3/30/2016
6 4/18/2016 4/24/2016 Testing Text Display
7 5/25/2016 5/01/2016 UI Webserver
8 5/02/2016 5/08/2016 Final Testing and Debugging

Parts List & Cost

Give a simple list of the cost of your project broken down by components. Do not write long stories here.

Design & Implementation

Hardware Design

LED Panels

LED Panel Front

The display panels use multiplexing to draw picture information, which means that the rows and columns are updated fast than the human eye can process. If the updating speed is fast enough, eyes will see a complete picture without flickering. The updating process is as follows

  • Select the row to be updated.
  • Output the desired column data on selected row.
Row Selection

Row selection is done by using a 3-to-8 address decoder (74HC138D). There are three address inputs to the display marked A, B and C. Based on the truth table, only one input is active (low) at a time.

Truth Table
Row Configuration

Since the panels has 16 rows, the 3-to-8 address decoder select rows in parallel. For example, when the 1st row (Row1) is selected, it also selects the 9th row (Row9). Using this technique implies that we must supply data for the columns for two unique rows at a time.

Rows with same name are selected together

The outputs of the decoder is connected to a P-Channel MOSFET, because the decoder itself can only handle low currents and cannot drive a row of LEDs directly. The P-Channel MOSFET provides the high current needed to drive a row of LEDs.

Output Mosfets

Hardware Interface

In this section, you can describe how your hardware communicates, such as which BUSes used. You can discuss your driver implementation here, such that the Software Design section is isolated to talk about high level workings rather than inner working of your project.

PCB Design

The LED panels use 74HC245 line drivers, these transceivers require 5v logic levels whereas the SJONE board only supports 3.3v logic. In order to drive the LED panels from 3.3v GPIO pins of the SJONE board, level-shifting IC is used to level shift signals from 3.3V to 5V and shield the SJONE board GPIOs from overloading. For this purpose, a PCB was designed in EAGLE. The PCB attaches to GPIO pins of SJONE board and provides easily accessible, level-shifted output for the LED panels. The PCB also breaks-out free pins so that they can be used for other purposes.

Schematic Design
PCB of Board

Software Design

Show your software design. For example, if you are designing an MP3 Player, show the tasks that you are using, and what they are doing at a high level. Do not show the details of the code. For example, do not show exact code, but you may show psuedocode and fragments of code. Keep in mind that you are showing DESIGN of your software, not the inner workings of it.

Implementation

This section includes implementation, but again, not the details, just the high level. For example, you can list the steps it takes to communicate over a sensor, or the steps needed to write a page of memory onto SPI Flash. You can include sub-sections for each of your component implementation.

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.

Include sub-sections that list out a problem and solution, such as:

My Issue #1

Discuss the issue and resolution.

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

Upload a video of your project and post the link here.

Project Source Code

References

Acknowledgement

Any acknowledgement that you may wish to provide can be included here.

References Used

List any references used in project.

Appendix

You can list the references you used.