skamo3/team-pilot

SEA:ME 2nd Project

Before start

• Before following this document, You must have to do first.
• Assemble Pi Racer & Move

Table of Contents

Complete Architecture

• Simple project architecture
  • Receive sensor data from Arduino and transfer it to Raspberry Pi using CAN Bus
  • Raspberry Pi uses the DBus server to manage the data it receives and delivers the data it needs for each application

Basics knowledge of the Architecture

What is Arduino?

• Micro Controller
  • Small electronic device that can easily handle various movements such as read data from sensors or use data to control motors.
  • C language (or C++) and Arduino IDE enable simple coding
  • Consists of Regulator, Circuit Element, GPIO
  • Peripherals allow direct control of external devices
  • More Information of Arduino

GPIO

• General Purpose Input/Output
• Uncommitted digital signal pin on an integrated circuit or electronic circuit board which may be used as an input or output, or both, and is controllable by software.

What is Raspberry Pi?

• Micro Processor
  • Similar to Arduino, but called Processor because it can have various OSs
  • Unlike Arduino, there is no peripheral device and controls the device using an internal transistor
  • Powerful performance in computational processing, which is useful for complex computational processing such as video and graphics
  • Raspberry Pi official document

What is CAN(Controller Area Network)?

• Standard communication protocol designed for vehicles to communicate with each other within a vehicle
• ECUs in the vehicle communicate using the CAN protocol

Advantage

• Multi-Master

  • All nodes are bus masters and whenever the bus is empty they can send information

• Twisted Pair Wire

  • Strong against electrical noise due to electrically differentiated communication using two lines : CAN_H, CAN_L
  • Scalability. Only need to connect to two lines, No matter how many ECUs.

• Message-Oriented Protocol

  • Use ID based on message priority. Use them to distinguish messages
  • Multiple messages come in at the same time, carry out the priority ID message

ECU

• Electronic Control Unit
• Electronic control device used in a car

What is D-Bus?

• System for IPC(Inter-Process Communication)

• A bus system that enables various processes with different characteristics to communicate with each other

• D-Bus is a service daemon that runs in the background that uses the bus daemon to communicate functions and communications between applications

  • Two type of D-Bus daemon
    1. D-Bus System bus
       • Communicate with kernel and system-wide events
       • Any application is prevented from spoofing
    2. D-Bus Session bus
       • daemon attached to each user session
       • Used to communicate with other applications within the same system
       • Receive messages from the system bus

Check D-bus service in terminal
ps -ef | grep dbus-demon
Separated by behind word

• --system or --session

Key Terms and Concepts

• Bus name(Service name)
  • Unique name for 1 connection
  • Automatically generated when connected to D-Bus daemon and can be set up by the user themselves
  • Names once used are non-reusable and must not be duplicated
• Object path
  • D-bus is a Peer-to-Peer protocol in which all messages sent and received are source and purposeful
  • Address used to send and receive messages
    • Written like "/org/example/Test"
  • Multiple object paths can be assigned differently than a business name
  • Object provides one or more interfaces
• Interface
  • Name of grouping Method and Signal
  • Interface is used as the namespace for each method
  • example

    <?xml version="1.0" ?>
    	<node name="/org/freedesktop/DBus/Example/Echo">
    		<interface name="org.freedesktop.DBus.EchoDemo">
    			<method name="HelloString">
    				<arg type="s" name="name" direction="in"/>
    				<arg type="s" name="greeting" direction="out"/>
    			</method>
    			<signal name="EchoCount">
    				<arg type="y" name="count"/>
    			</signal>
    		</interface>
    	</node>

    • Method
      • Can be called by another object
      • Can optionally have Input and Output
    • Signal
      • Kind of broadcast message. Send to one object to all objects registered with that signal

  • Message
    • Data passed between processes
    • Method Call Message
    • Method Return Message
    • Error Message
    • Signal Message
    • Header and Body

Prepare the materials

Pi RacerPro & Raspberry Pi	Can Module MCP 2515 * 2	Arduino Nano(HIMALAYA

• Basically, These materials can make communication. After connecting, you can connect Arduino with other modules(speed sensor, temperature sensor, etc) using Breadboard.

Make communication

Blueprint

Raspberry Pi <-> MCP2515 <-> MCP2515 <-> Arduino Nano <-> other modules

Raspberry Pi <-> MCP2515

Raspberry Pi	MCP2515
GND[20]	GND
GPIO25[22]	INT
GPIO8[24]	CS
GPIO10[19]	SI
GPIO9[21]	S0
GPIO11[23]	SCK
5V	VCC

• VCC & 5V
  • You must find another 5Voltage socket in Pi Racer. Raspberry Pi 5V is already used for connecting Raspberry Pi & Pi Racer.

Arduino Nano <-> MCP2515

Arduino Nano	MCP2515
D2	INT
D13	SCK
D11	SI
D12	S0
D10	CS
GND	GND
5V	VCC

• Use Breadboard to connect Arduino and MCP2515
• Later, Sensors can be connected to Arduino with Breadboard

MCP2515 <-> MCP2515

MCP2515	MCP2515
CAN_H	CAN_H
CAN_L	CAN_L

Send & Receive Data

• Raspberry-Pi and Arduino communication with CAN communicate library

Set Can

1. Setting CAN interface on Raspberry Pi

   • Add the following line to your /boot/config.txt file:

      dtoverlay=mcp2515-can0,oscillator=16000000,interrupt=25
      dtoverlay=spi-bcm2835-overlay

     • oscillator : should be set to the actual crystal frequency found on your MCP2515
     • interrupt : specifies the Raspberry PI GPIO pin number

   • Reboot your Raspberry Pi and Check this line

      [   20.248951] CAN device driver interface
      [   20.499256] mcp251x spi0.0 can0: MCP2515 successfully initialized.
     

2. Bring up the CAN interfaces
   2-1. Manually bring up

   • Follow this command in terminal
     sudo /sbin/ip link set can0 up type can bitrate 500000
     • Check your CAN bus bitrate and write correct number

   2-2. Automatically bring up on boot

   • Edit your /etc/network/interfaces file and add this line

      auto can0
      iface can0 inet manual
      	pre-up /sbin/ip link set can0 type can bitrate 500000 triple-sampling on restart-ms 100
      	up /sbin/ifconfig can0 up
      	down /sbin/ifconfig can0 down

• Check CAN module
  • Enter this command and check output
  

3. CAN-utils

   • CAN-utils is a collection of extremely useful debugging tools using the SocketCAN interface
   • list of applications
     • candump : Dump can packets – display, filter and log to disk.
     • canplayer : Replay CAN log files.
     • cansend : Send a single frame.
     • cangen : Generate random traffic.
     • canbusload : display the current CAN bus utilisation.
   • Install CAN utils
     • CAN-utils Git repository
     • Pre-compiled binaries can be installed using:
       sudo apt-get install can-utils

4. CAN data send or receive with CAN utils

   • Make random data
     cangen can0
   • Receive can data and check in terminal
     candump can0
   

Reference link

Send sensor data Arduino -> Raspberry-Pi

Receive sensor data on Raspberry-Pi with code