S15: CAN controlled RGB LED cubes
Contents
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
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.
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
- 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
Show a simple table or figures that show your scheduled as planned before you started working on the project. Then in another table column, write down the actual schedule so that readers can see the planned vs. actual goals. The point of the schedule is for readers to assess how to pace themselves if they are doing a similar project.
| Week# | Start Date | Task | Status | Completion Date |
|---|---|---|---|---|
| 1 | 3/15 | Finalizing & ordering components
-Going through the requirements of the project -Order hardware components based on the final list |
Completed | 3/17 |
| 2 | 3/27 | 3x3x2 LED cube testing with SPI interfacing
-Studying the SC74HC595 shift register datasheet -Constructing a 3x3x2 LED cube for testing purpose -Interfacing of shift register using SSP1 with LPC1758 -Cascading of 4 shift registers using SSP1 to control anodes & RGB cathodes |
Completed | 4/10 |
| 3 | 4/8 | Bluetooth Interface with SJone board through Android APK
-Testing the AT commands of Bluetooth HS-06 V1.06 module using hyperterminal(Completed) -Testing interfacing of bluetooth using UART2(Completed) |
Completed | 4/17 |
| 4 | 4/8 | Android application
-Communication between bluetooth module and an android application(Completed) |
Completed | 4/25 |
| 5 | 4/16 | 4x4x4 LED cube construction
-Building 2 LED cubes -Interfacing & cascading of the shift registers with SJone boards to control 16 anodes and 12 cathodes using SIPO configuration of shift register -Interfacing of LED cubes with shift registers |
Completed | 4/26 |
| 6 | 4/20 | CAN protocol programming
-Studying the CAN protocol datasheet(Completed) -Setting up the interface of CAN transceiver and SJone boards(Completed) -Initially making two-nodes CAN configuration(Completed) -Three nodes CAN configuration(Completed) |
Completed | 4/30 |
| 7 | 4/27 | Generating patterns on LED cubes
-Building libraries for generating Alphabets & numbers on the LED cubes |
In Progress | 5/7 |
| 8 | 5/1 | Implementing FreeRTOS for the system
-Implementing queue RTOS feature to connect the bluetooth interface and the CAN interface of the LPC1758 board |
Completed | 5/10 |
| 9 | 5/10 | Final Debugging & testing | In Progress | 5/15 |
Parts List & Cost
| # | Components | Quantity | Price($)/component |
|---|---|---|---|
| 1 | RGB LEDs pack of 100 | 2 | 9.95 |
| 2 | CAN transceivers | 15 | Free |
| 3 | Shift registers, SC74HC595 | 10 | 1.49 |
| 4 | SJone boards | 3 | 80 |
| 5 | Bluetooth module | 1 | 20 |
| 6 | Steel wire | 1 | 8 |
| 7 | Soldering kit | 1 | ~40 |
| 8 | Jumper wires(each type) | 1 | 25 |
| 9 | ULN 2003 | 4 | 12 |
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 below 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 and 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.
Bluetooth module Interface
*Data from Android application is sent over Bluetooth to 'Bluetooth receiver (HC-06)'. Bluetooth receiver is connected to UART 2 as per below diagram.
Hardware Design
- Bluetooth module is connected with UART2 on SJSU-One board. HC-06 needs 5V, which is being provided externally. Tx Pin of HC-06 is connected with P2.9 (Rx of Uart2), Rx pin is connected with P2.8 of Sjsu-One board, GND is made common and Vcc is connected with 3.3V (took from SJSU one board). Below is the pin diagram from Bluetooth-Uart connections.
Software Design
CAN Communication
- A task is created for CAN transmission at transmission side and this task checks for the signal from the UART Interrupt handler; on receiving the signal, data on a requested board will be sent using CAN protocol.
- Receiver side listens only to the messages from specific message id and on receiving the message, it updates the data buffer.
Bluetooth module Interface
- Protocol used to send data from application: 8-byte data (or less ) send over Bluetooth will be displayed on the one of the LED cubes. If we need to display characters ‘SJSU’ on LED cube connected to Sj-One board 1. Then user should transmit < 1SJSU$>; where first field is board on which data is to be displayed followed by words to display, ‘$’ sign is must be added at the end to indicate the end of string(data). If the data to be displayed is 8 bytes long, then ’$’ is not required.
- The first flied should be either 1 or 2 (to select from one of 2 LED cubes).
- In our project, we are using UART2 connection with Bluetooth module. Baud rate is set at 9600 bps.Once the data is sent over mobile to Bluetooth device, Receive interrupt will occur and interrupt handler will be called. Interrupt handler sends signal to respective task(CAN Transmitter task) and task which is waiting on signal then reads the FIFO. The first character read by task will be ‘board number’ followed by words to be printed and ‘$’ sign. On reading the whole message the task sends message to CAN transmitter to send data over CAN bus.
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
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
- Sending a long string of data from Application: This issue was mainly because we were not using Interrupts hence FIFO was overflowing which results into loss of data.
- Getting garbage value during read from UART2: This was because of baud rate, on using baud rate 9600 with precision ±3 %, this issue got resolved.
Conclusion
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Project Video
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Project Source Code
References
Acknowledgement
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References Used
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Appendix
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