Difference between revisions of "Raspberry PI"

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</source>
 
</source>
 
=== Python Helper Scripts ===
 
=== Python Helper Scripts ===
==== obdii_redirect.py ===
+
==== obdii_redirect.py ====
 
<source lang='python'>
 
<source lang='python'>
 
# WF 2017-02-10
 
# WF 2017-02-10

Revision as of 10:01, 24 January 2019

To run on a Raspberry PI you need a properly configured device. See e.g. http://ion.bitplan.com/index.php/Ion2017-07-18#Raspberry_PI

Hardware

See e.g. 31jEGhZmPdL.jpg

91zSu44%2B34L._SL1500_.jpg

Raspberry Setup

You'll find setup guides all over the internet here are just two links:

Software configuration

cat /etc/os-release
PRETTY_NAME="Raspbian GNU/Linux 9 (stretch)"
NAME="Raspbian GNU/Linux"
VERSION_ID="9"
VERSION="9 (stretch)"
ID=raspbian
ID_LIKE=debian
HOME_URL="http://www.raspbian.org/"
SUPPORT_URL="http://www.raspbian.org/RaspbianForums"
BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"

Java 8 installation

apt-get install oracle-java8-jdk

Run script

If you have an official touchscreen you can control the brightness of the screen with the darkmode button of can4eve.

You might want to make sure that you use the run script to start the app. The important lines are:

sudo chmod 0664 /sys/class/backlight/rpi_backlight/brightness
sudo chown root.pi /sys/class/backlight/rpi_backlight/brightness

Autostart

Example Can4Eve.desktop file to be placed in .config/autostart of your user. Please adapt the exec line to where you installed can4eve

[Desktop Entry]
Type=Application
Name=Can4Eve
Comment=Onboard Diagnostic software for Electric Vehicles
NoDisplay=false
Exec=/home/wf/source/java/can4eve/run

Bluetooth

see https://www.raspberrypi.org/forums/viewtopic.php?t=214373

check connection

Bluetooth services

service bluetooth status
● bluetooth.service - Bluetooth service
   Loaded: loaded (/lib/systemd/system/bluetooth.service; enabled; vendor preset
   Active: active (running) since Thu 2019-01-24 08:51:05 CET; 3min 2s ago
     Docs: man:bluetoothd(8)
 Main PID: 849 (bluetoothd)
   Status: "Running"
   CGroup: /system.slice/bluetooth.service
           └─849 /usr/lib/bluetooth/bluetoothd

Pairing

Pair the device using the Graphical User Interface Bluetooth button in the top right. You will not be able to connect the message is "Connection failed - No usabel services on this device". We'll work around this with some python helper software Check result with commmand line:

bluetoothctl
[NEW] Controller B8:27:EB:2E:AB:2B pito [default]
[NEW] Device 00:04:3E:9F:A3:C0 OBDLink LX
quit

Python Helper Scripts

obdii_redirect.py

# WF 2017-02-10
# Python access to OBD trial
import serial
import time
import logging
import string
import io
import os
import sys

#
# 
# Elm327 helper class
#
class Elm327:
  # initialize the serial communication
  def __init__(self,port="/dev/rfcomm0",baud=115200,timeout=1):
    self.log = logging.getLogger(__name__)
    self.port=port
    self.baud=baud
    self.timeout=timeout
    self.ser = serial.Serial(port,baud)
    self.ser.timeout=timeout

  # send the given string 
  def send(self,s):
    if (self.ser):
      self.ser.flushInput()
      self.ser.write(bytes(s + '\r\n', encoding = 'utf-8'))
      self.ser.flush()
      return self.read()
    else:
      raise RuntimeError('Serial port not initialized') from error

  # read data from the serial device
  # http://stackoverflow.com/a/13018267/1497139
  def read(self):
    if (not self.ser):
      raise RuntimeError('Serial port not initialized') from error
    buffer=bytearray()
    time.sleep(1)
    # get all available data
    waiting=self.ser.inWaiting()
    if (waiting>0):
      readbytes= self.ser.read(self.ser.inWaiting())
    else:
      readbytes=[]
    # check 
    if not readbytes:
      self.log.warning("read from "+self.port+" failed")

    buffer.extend(readbytes)

    return buffer.decode()

  def close(self):
    if (not self.ser):
      raise RuntimeError('Serial port not initialized') from error
    self.ser.close()

  def dcmd(self,cmd):
    response=self.send(cmd)
    print(response)

#elm=Elm327("/dev/rfcomm0",115200)
elm=Elm327()
elm.dcmd("ATD")
elm.dcmd("ATZ")
elm.dcmd("ATE0") # switch off echo
elm.dcmd("ATL1") # switch on newlines
elm.dcmd("ATI")
elm.dcmd("ATSP6")
elm.dcmd("ATDP")
elm.dcmd("ATH1")
elm.dcmd("ATD1")
elm.dcmd("ATCAF0")
if (len(sys.argv) >1):
  pid=sys.argv[1]
  elm.dcmd("ATCRA "+pid)
  elm.dcmd("AT MA")
  while True:
    response=elm.read()
    print(response)
elm.close()

#s = input('Enter AT command --> ')
#print ('AT command = ' + s)
#ser.timeout = 1
#response = ser.read(999).decode('utf-8')
#print(response)
#ser.close()

tcp_serial_redirect.py

#!/usr/bin/env python
#
# Redirect data from a TCP/IP connection to a serial port and vice versa.
#
# (C) 2002-2016 Chris Liechti <cliechti@gmx.net>
#
# SPDX-License-Identifier:    BSD-3-Clause

import sys
import socket
import serial
import serial.threaded
import time
import datetime


class SerialToNet(serial.threaded.Protocol):
    """serial->socket"""

    def __init__(self):
        self.socket = None

    def __call__(self):
        return self

    # callback function
    # this is called by the ReaderThread on receiving data from
    # the serial device
    def data_received(self, data):
        if self.socket is not None:
            # first send data over network
            self.socket.sendall(data)
            # optionally show it for debug
            if (self.debug):
               print("r"+datetime.datetime.now().isoformat()+":"+data)

if __name__ == '__main__':  # noqa
    import argparse

    parser = argparse.ArgumentParser(
        description='Simple Serial to Network (TCP/IP) redirector.',
        epilog="""\
NOTE: no security measures are implemented. Anyone can remotely connect
to this service over the network.

Only one connection at once is supported. When the connection is terminated
it waits for the next connect.
""")

    parser.add_argument(
        'SERIALPORT',
        help="serial port name")

    parser.add_argument(
        'BAUDRATE',
        type=int,
        nargs='?',
        help='set baud rate, default: %(default)s',
        default=9600)

    parser.add_argument(
        '-d', '--debug',
        action='store_true',
        help='debug',
        default=False)

    parser.add_argument(
        '-q', '--quiet',
        action='store_true',
        help='suppress non error messages',
        default=False)

    parser.add_argument(
        '--develop',
        action='store_true',
        help='Development mode, prints Python internals on errors',
        default=False)

    group = parser.add_argument_group('serial port')

    group.add_argument(
        "--parity",
        choices=['N', 'E', 'O', 'S', 'M'],
        type=lambda c: c.upper(),
        help="set parity, one of {N E O S M}, default: N",
        default='N')

    group.add_argument(
        '--rtscts',
        action='store_true',
        help='enable RTS/CTS flow control (default off)',
        default=False)

    group.add_argument(
        '--xonxoff',
        action='store_true',
        help='enable software flow control (default off)',
        default=False)

    group.add_argument(
        '--rts',
        type=int,
        help='set initial RTS line state (possible values: 0, 1)',
        default=None)

    group.add_argument(
        '--dtr',
        type=int,
        help='set initial DTR line state (possible values: 0, 1)',
        default=None)

    group = parser.add_argument_group('network settings')

    exclusive_group = group.add_mutually_exclusive_group()

    exclusive_group.add_argument(
        '-P', '--localport',
        type=int,
        help='local TCP port',
        default=7777)

    exclusive_group.add_argument(
        '-c', '--client',
        metavar='HOST:PORT',
        help='make the connection as a client, instead of running a server',
        default=False)

    args = parser.parse_args()

    # connect to serial port
    ser = serial.serial_for_url(args.SERIALPORT, do_not_open=True)
    ser.baudrate = args.BAUDRATE
    ser.parity = args.parity
    ser.rtscts = args.rtscts
    ser.xonxoff = args.xonxoff

    if args.rts is not None:
        ser.rts = args.rts

    if args.dtr is not None:
        ser.dtr = args.dtr

    if not args.quiet:
        sys.stderr.write(
            '--- TCP/IP to Serial redirect on {p.name}  {p.baudrate},{p.bytesize},{p.parity},{p.stopbits} ---\n'
            '--- type Ctrl-C / BREAK to quit\n'.format(p=ser))

    try:
        ser.open()
    except serial.SerialException as e:
        sys.stderr.write('Could not open serial port {}: {}\n'.format(ser.name, e))
        sys.exit(1)

    ser_to_net = SerialToNet()
    ser_to_net.debug=args.debug 
    serial_worker = serial.threaded.ReaderThread(ser, ser_to_net)
    serial_worker.start()

    if not args.client:
        # open the socket as a streaming socket
        srv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        srv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        srv.bind(('', args.localport))
        srv.listen(1)
    try:
        intentional_exit = False
        while True:
            if args.client:
                host, port = args.client.split(':')
                sys.stderr.write("Opening connection to {}:{}...\n".format(host, port))
                client_socket = socket.socket()
                try:
                    client_socket.connect((host, int(port)))
                except socket.error as msg:
                    sys.stderr.write('WARNING: {}\n'.format(msg))
                    time.sleep(5)  # intentional delay on reconnection as client
                    continue
                sys.stderr.write('Connected\n')
                client_socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
                #~ client_socket.settimeout(5)
            else:
                sys.stderr.write('Waiting for connection on {}...\n'.format(args.localport))
                client_socket, addr = srv.accept()
                sys.stderr.write('Connected by {}\n'.format(addr))
                # More quickly detect bad clients who quit without closing the
                # connection: After 1 second of idle, start sending TCP keep-alive
                # packets every 1 second. If 3 consecutive keep-alive packets
                # fail, assume the client is gone and close the connection.
                try:
                    client_socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_KEEPIDLE, 1)
                    client_socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_KEEPINTVL, 1)
                    client_socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_KEEPCNT, 3)
                    client_socket.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
                except AttributeError:
                    pass # XXX not available on windows
                client_socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
            try:
                ser_to_net.socket = client_socket
                # enter network <-> serial loop
                while True:
                    try:
                        # read data from serial                    
                        data = client_socket.recv(2048)
                        if not data:
                            break
                        ser.write(data)                 # get a bunch of bytes and send them
                        if (args.debug):
                           print("s"+datetime.datetime.now().isoformat()+":"+data)
                    except socket.error as msg:
                        if args.develop:
                            raise
                        sys.stderr.write('ERROR: {}\n'.format(msg))
                        # probably got disconnected
                        break
            except KeyboardInterrupt:
                intentional_exit = True
                raise
            except socket.error as msg:
                if args.develop:
                    raise
                sys.stderr.write('ERROR: {}\n'.format(msg))
            finally:
                ser_to_net.socket = None
                sys.stderr.write('Disconnected\n')
                client_socket.close()
                if args.client and not intentional_exit:
                    time.sleep(5)  # intentional delay on reconnection as client
    except KeyboardInterrupt:
        pass

    sys.stderr.write('\n--- exit ---\n')
    serial_worker.stop()