Cars and Computers: Building a Java Carputer

Cars and Computers: Building a Java Carputer
Simon Ritter
Head of Java Technology Evangelism
Oracle Corp.
Twitter: @speakjava

Copyright © 2014, Oracle and/or its affiliates. All rights reserved.
Safe Harbor Statement
The following is intended to outline our general product direction. It is intended for
information purposes only, and may not be incorporated into any contract. It is not a
commitment to deliver any material, code, or functionality, and should not be relied upon
in making purchasing decisions. The development, release, and timing of any features or
functionality described for Oracle’s products remains at the sole discretion of Oracle.
2

Cars And Computers

My First Car: 1981
• No electronics
– Well, it had a radio
• Purely electromechanical
– Points/Distributor
– Carburettor/Manual choke
– Drum brakes
– Dynamo
– Lights, horn, wipers, fan, ignition switch
1971 Mini Clubman 1000

Car Wiring: 1970s
Image coutesy of Haynes manuals

My Current Car
• Lots of electronics
– Engine Control Unit (ECU)
– Fuel Injection/Electronic timing
– “Fly-by-wire” throttle
– Anti-lock Braking System (ABS)
– Electronic Stability Program (ESP)
– Magnetorheological Suspension
– Satellite navigation
– Auto-sensing wipers and lights
2011 Audi S3

Bus architecture means substantially less wiring
Car Wiring: 2011
Convenience Bus Infotainment Bus Powertrain Bus

The Java Carputer
(Mark 1)

Carputer Design Objectives
• Display realtime data
• Engine performance (Power, Torque, Load)
• Driver data (Throttle position, steering angle, braking force, etc)
• G-Forces on car
• Graphed data for time-based analysis

Carputer Hardware Architecture
USB WiFi Dongle
Touch Screen
Accelerometer
HDMI USB
I2C
12V Car
Converter
ELM327
Car
Service
Port
5V USB

ELM327
• WiFi or Bluetooth connection to OBD-II
• Fixed IP address, Ad-hoc networking
• Need to configure Raspberry Pi
– /etc/network/interfaces
• AT style commands for control
• Non-AT commands are assumed to be OBD-II
– Simple request-response interaction
– Easy to write Java code to handle this
Cheap way to hack your car

Touchscreen
• 2 DIN fitting size
– Ideal for centre console
• HDMI input
– Specifically marketed for Raspberry Pi
• USB connection for touch screen
Lots of things available on eBay

Hardware Fitting Challenges
Touchscreen

Accelerometer
• Sparkfun breakout board MPU 9150
– 9 DoF sensor (accelerometer, gyroscope, compass)
• Communications via I2C
– Configure Raspberry Pi /etc/modules
• i2c-bcm2708, i2c-dev
• i2c-detect -y 1 to get address
– Compass communication is a bit more complicated
• Second I2C bus

Accelerometer Code
Using Pi4J Library on Java SE Embedded
I2CBus bus = I2CFactory.getInstance(I2CBus.BUS_1);
I2CDevice device = bus.getDevice(0x68);
/* Start sensing */
device.write(0x6B, (byte)0b00000000);
device.write(0x6C, (byte)0b00000000);
/* Set configuration */
device.write(0x1B, (byte)0b00011000); // Gyroscope
device.write(0x1C, (byte)0b00000100); // Accelerometer
device.read(0x3B, accelData, 0, ACCEL_PACKET_SIZE);

Carputer Software Architecture
• Screens based
– Splash screen
– Basic and advanced car data
– G forces on car
– Graphed results of different parameters
• Simple UI
– Can’t read numbers when driving
• Touchscreen to switch screens
– Repurpose existing car controls to change screen?
Realtime Data

Take Inspiration From Others
UI Design Ideas
Renault Megane Sport

UI Design Ideas
Tesla

UI Design Ideas
Lamborghini Reveton

Simple Data Display Control
• Only uses 3 nodes
– Polygon
– Rectangle
– Line
– Labels are optional
• Displays
– Current value
– Maximum value since start (resetable)
• Simple to understand from a glance

Splash Screen
UI Screens

UI Screens

The Java Carputer
(Mark 2)

Carputer Hardware Architecture
25
USB via FTDICrossover ethernet
Infra red
Thermal sensor
CAN High
CAN Low
OBD2 Service Port
Wi-Fi
Accelerometer/
Gyro/Compass
I2C
USB
UART
Serial
GPSHeart Rate Monitor
USB
Video Camera
Raspberry Pi Model B+
7” Touch secreen
USB
SDR/TPMS
CAN Bus

Tracking Position With GPS
• AdaFruit Ultimate GPS breakout
– 10Hz read rate
– Serial interface
• Very simple configuration
– Disable /dev/ttyAMA0 on Pi as console
– 9600 8N1
– Read data using librxtx-java
– Comma separated values $GPGGA and $GPVTG
– Need to handle frequent data corruption

Heart Rate Monitoring of the Driver
• Sparkfun board
– USB interface, serial connection
• Similar to GPS
– Use librxtx-java
– 9600, 8N1
• More complicated coding
– Actually need to send a read request!
• Some issues with wireless connection
– 80cm max, doesn’t work well through a Rapsberry Pi

In-car Video
• Becoming very common to avoid insurance issues
• Transcend DrivePro 200
– Built-in Wi-Fi
– iPhone app
• How to get video stream?
– Approached Transcend tech support
– Found VLC code
– Wireshark
– SYN/ACK, Yuck!
28
Camera Application
192.168.0.1 192.168.0.2
Port 9000 Port 43229
Port 8554 (RTSP) Port 60583

The Simplest Solution Is Often The Best
29
Push button using GPIO lines and Pi4J

Thermal Sensors For Brakes and Tyres
The Goal

Infra-Red Thermometer
• MLX90614 breakout board
– I2C interface seemed problematic on the Pi
– Also has serial interface
– Use FTDI breakout board
– 4 wires becomes simple serial interface
31
The Reality

Thermal Sensor Data
• Provides continuous reading as lines of text (e.g. 73.2F)
– Don’t like Fahrenheit, wanted Celcius
– Lambdas and Streams!
32
private double currentTemperature;
public void run() {
thermalReader.lines()
.mapToDouble(s -> Double.parseDouble(s.substring(0, s.length() - 1)))
.map(t -> ((t - 32) * 5 / 9))
.filter(t -> t != currentTemperature)
.peek(t -> listener.ifPresent(l -> l.temperatureChange(t)))
.forEach(t -> currentTemperature = t);
}

Thermal Sensor Data
• Provides continuous reading as lines of text (e.g. 73.2F)
– Don’t like Fahrenheit, wanted Celcius
– Lambdas and Streams!
33
private double currentTemperature;
public void run() {
thermalReader.lines()
.mapToDouble(s -> Double.parseDouble(s.substring(0, s.length() - 1)))
.map(t -> ((t - 32) * 5 / 9))
.filter(t -> t != this.currentTemperature)
.peek(t -> listener.ifPresent(l -> l.temperatureChange(t)))
.forEach(t -> this.currentTemperature = t);
}

Copyright © 2014, Oracle and/or its affiliates. All rights reserved. 34
Tyre Sensor
Fitting The Thermal Sensors

Brake Disk Sensor

Separate Pi in Engine Bay

• Simple server listens on port
• Carputer requests data
• Couple of issues
– Server needed reset for new
connection (bug to be fixed)
– How to tell which sensor is which
(ttyUSB0/ttyUSB1)
37
The Networked Car

• Rasperry Pi at over 50C
– After 10 minute drive
• New approach required
– Longer USB cables
– Put the Pi in the car
38
Internal Combustion Produces Heat

Getting Data From The CAN Bus
• Controller Area Network
• Used to connect many sensors, actuators and devices
– Without huge amounts of wiring
• Conveniently the CAN bus is connected to the OBD2 port
– Yes, the wiring is there
– No, the signals are not
– Presumably security measure from car manufacturers
– Boo!

Where There’s A Will There’s A Way

Where There’s A Will There’s A Way
Success! (And the car still works)

• Lawicel CAN bus to USB
• Serial device
• Sends decoded data
• Need to write a Java library
– CAN id
– Message data
• Then the hard part starts
– Figuring it all out
42
Electrical Connectivity Is Only The Start

Finished Data Capture System

Data Recording and Analysis

Display Collected Data
• JavaFX application
• Video stream
– Synchronised to data streams
• Data recorded as sequence of text records
– Comma separated values
– One line per sensor
– Time stamp
• Read all data in at start of application
– 15 minutes of data takes about 100ms
45

• Video (with controls)
• G-forces
• GPS co-ordinates/altitude
• Map of current position
• Speed (compare car and GPS)
• Bearing
• Engine load
• Fuel pressure
• Air intake temperature
• Coolant temperature
• Catalyst/exhaust temperature
• Tyre temperature
• Brake temperature
• Throttle position
• Engine RPM
• Heart rate
46
Data To Display

Conclusions & Resources

Conclusions
• Cars produce lots of data
• Use of sensors with Java is simple to collect (most) data
• Playback of data useful for insurance, fleet management, training
• Java and JavaFX make UI design simple

Resources and Links
• www.sparkfun.com
• www.adafruit.com
• www.raspberrypi.org
• blogs.oracle.com/speakjava
• Twitter: @speakjava

Demos

Cars and Computers: Building a Java Carputer

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