Difference between revisions of "S15: CAN controlled RGB LED cubes"

Revision as of 00:28, 6 May 2015

Grading Criteria

Project Title

CAN controlled RGB LED cubes

Abstract

In this project, data(1 byte) sent from an android application will be displayed in a 3D form on a LED cube. Two LED cubes will be connected to two different SJone boards, these SJone boards are connected to a third SJone board using CAN bus. The LED cubes will be connected to their respective SJ boards through shift registers. The boards will implement SSP protocol to communicate with the shift registers. A bluetooth module is connected to third SJone board. Android application sends data to be displayed along with the information about the SJone board(one of the LED cube) to be selected.

File:Basic Block Diagram.png

Objectives & Introduction

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Team Members & Responsibilities

• Chitrang Talaviya
  • LED cube design
  • Implementing CAN protocol
  • Bluetooth module interfacing
• Navjot Singh
  • Implementing CAN protocol
  • Bluetooth module interfacing
  • FreeRTOS environment
• Anuj Korat
  • LED cube design
  • Generating dynamic patterns
  • Implementing SSP with the shift registers
• Daamanmeet Paul
  • Android application development
  • Generating different characters on LED cube

Schedule

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Parts List & Cost

Design & Implementation

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Hardware Design

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

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.

Shift registers have been used to communicate betwen the SJone board and the LED cubes. As the dimension of the cue is 4 x 4 x 4, it needs a total of 28 pins to control it, 16 pins to control 16 groups of 4 LED anodes and 12 pins to control 4 planes of the RGB lines. As we do not have that many pins on SJone board, we will be using 4 Serial- input-parallel-output shift registers to drive the LED terminals. This eases our job as only 4 pins are used from the board to drive 28 LED terminals.

The communication bus used between the LPC1758 board and the shift registers is SSP-Synchronous Serial Port. The driver written for the communication is as shown in Fig. All the shift registers are cascaded, meaning the serial output of one, connected to the serial input of the other. This way a total of 32 bits of serial data from the board can be converted into parallel outouts which are given to its respective LED terminals.

Two nodes CAN configuration

Hardware setup

• The below diagram is for Two nodes CAN configuration. CAN1 is used on SJBoard with CAN transceiver MCP 2551. The interfacing with MCP2551 and SJBoard is shown with the pin diagram. This setup is for communication between two SJBoards using CAN protocol. Here, Termination resisters value between CANH and CANL is 120 Ohms. The RS pin is used to select High-speed, Slope-control or Standby modes via an external biasing resistor. Here, this Rs pin is connected to the ground directly. External 5V power supplier is used to power up both MCP 2551 CAN transceiver ICs. P0.0 and P0.1 on SJBoard are for RXD1 and TXD1 respectively for CAN1.

Software design

• In this configuration one SJBoard is transmitting a data frame of a particular message ID. Other SJBoard is receiving the data frame of any message ID.

File:CANdia.png

Software Design

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Android Application Development:-

Tools used to Develop Android Application:

• Android Studio based on IntelliJ IDEA.

• Java Development kit 7 by Oracle.

• Android ADB interface.

• Android API 21 platform.

Application Features:

• Bluetooth pairing up to 6 devices at a time.

• Facility to change Transmission Protocol within the Application.

• Send Data serially to any serial Bluetooth Device.

• Receive Data serially from any Bluetooth device using same protocol.

Application development Procedure:-

Application is developed upon the sample code provided by http://developer.android.com/guide/topics/connectivity/bluetooth.html & http://bitfountain.io/courses/mini-android

Bluetooth APIs setup available in the android bluetooth package:

• BluetoothAdapter

Used for the local Bluetooth adapter (Bluetooth radio). The BluetoothAdapter is the entry-point for all Bluetooth interaction. It is used to discover other Bluetooth devices, query a list of bonded (paired) devices, instantiate a BluetoothDevice using a known MAC address, and create a BluetoothServerSocket to listen for communications from other devices.

Android platform includes support for the Bluetooth framework that allows a device to wirelessly exchange data with other Bluetooth devices. Android provides Bluetooth API to perform these different operations.

Steps

1. Scan for other Bluetooth devices

2. Get a list of paired devices

3. Connect to other devices through service discovery

Android provides BluetoothAdapter class to communicate with Bluetooth. Create an object of this calling by calling the static method getDefaultAdapter(). Its syntax is given below.

private BluetoothAdapter BA;
BA = BluetoothAdapter.getDefaultAdapter();

In order to enable the Bluetooth of your device, call the intent with the following Bluetooth constant ACTION_REQUEST_ENABLE. Its syntax is

Intent turnOn = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(turnOn, 0);      

Apart from this constant, there are other constants provided the API , that supports different tasks. They are listed below.

Constant & description:

1        ACTION_REQUEST_DISCOVERABLE: This constant is used for turn on discovering of bluetooth
2        ACTION_STATE_CHANGED: This constant will notify that Bluetooth state has been changed
3        ACTION_FOUND: This constant is used for recieving information about each device that is discovered

Once you enable the Bluetooth , you can get a list of paired devices by calling getBondedDevices() method. It returns a set of bluetooth devices. Its syntax is.

private Set<BluetoothDevice>pairedDevices;
pairedDevices = BA.getBondedDevices();

Apart form the pariredDevices , there are other methods in the API that gives more control over Blueetooth. They are listed below.

Sr.No Method & description

1 enable(): This method enables the adapter if not enabled

2 isEnabled(): This method returns true if adapter is enabled

3 disable(): This method disables the adapter

4 getName(): This method returns the name of the Bluetooth adapter

5 setName(String name): This method changes the Bluetooth name

6 getState(): This method returns the current state of the Bluetooth Adapter.

7 startDiscovery(): This method starts the discovery process of the Bluetooth for 120 seconds.

Implementation

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Testing & Technical Challenges

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My Issue #1

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Conclusion

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Project Video

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Project Source Code

• Sourceforge Source Code Link

References

Acknowledgement

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References Used

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Appendix

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