wall-e

Robot's remote control application suite.

##Description Suite consists of two applications: Control application and Remote application. Former is designed to control periferal components and sensors of robot. It provides graphical UI and communication with remote side. Last one is used for remote configuration, monitoring and control. Communication between applications is based on TCP protocol. Both applications are built with open sourse version of Qt. Video and audio streams are implemented using gstreamer and VLC packages.

Remote application:

Below is reference car robot platform based on AT91SAM9G45-EVK board. The main features are web-camera with video and audio support, four motors, battery, battery sensor, ultrasonic sensor, hall sensor, WiFi AP, horn and headlights. The robot has its own touchscreen display for in place diagnostic and configuration.

Build

Remote application requirements:

Windows 7/Kubuntu 14.04: Qt 5.3.2 32bit, g++ 4.9.2, VLC library 2.1.4.

Control application requirements:

Embedded linux: buildroot-2013.05 (Qt embedded 4.8.4, g++ 4.7.3).
Kubuntu 14.04: Qt 4.8.4, g++ 4.7.3

Qt project configuration

Steps to configure Qt Creator for embedded Linux in order to build Control application:

1. Projects -> Manage Kits -> Build & Run -> Qt Versions -> Add...
   Version Name: Qt 4.8.4 (qt-4.8.4) buildroot
   qmake location: <Buildroot folder>/output/build/qt-4.8.4/bin/qmake
2. Projects -> Manage Kits -> Build & Run -> Compilers -> Add -> GCC
   Name: ARM_BUILDROOT_GCC
   Compiler Path: <Buildroot folder>/output/host/usr/bin/arm-linux-gcc
3. Projects -> Manage Kits -> Build & Run -> Kits -> Add
   Name: buildroot-arm-none-eabi-gcc
   Sysroot: <Buildroot folder>/output/target
   Compiler: ARM_BUILDROOT_GCC
   Qt version: Qt 4.8.4 (qt-4.8.4) buildroot

##Demo run Control application and remote application can run on the same PC for demo purposes.

###Host requirements: Kubuntu 14.04, gstreamer 0.10.36 + plugins.

###Execute applications:

1. Create ethernet device alias with 192.168.3.1 IP:
   $ sudo ifconfig eth0:0 192.168.3.1 up
2. Create regular Desktop build configuration for Control application in Qt Creator.
3. Execute Desktop build of Control application.
4. Execute Remote application and press "Connect" button.
5. After connection is established connection status is "Connected", video from PC web-camera is shown and audio from PC microphone can be heard in headphones.

##AT91SAM9G45-EVK car robot platform

Root FS

• Download Buildroot 2013.05 or later from http://buildroot.uclibc.org.
• Copy configuration file and update device table:
  $ cp platform/at91sam9g45-ekes/buildroot-2013.05/.config <Buildroot folder>/
  $ cp platform/at91sam9g45-ekes/buildroot-2013.05/system/device_table_dev.txt <Buildroot folder>/system/
  $ mkdir -p <Buildroot folder>/system/skeleton/dev/snd
  $ make menuconfig
  $ make

Kernel

• Build Linux 2.6.30 with patches provided along with AT91SAM9G45-EVK boad and configuration file located in platform/at91sam9g45-ekes/linux-2.6.30/ folder. Refer to board's manual.

Flashing board

• Program board with default AT91SAM9G45-EVK bootloaders, custom kernel and root FS. Refer to board's manual.

Battery ADC

• Linux configuration file turns on support of PCF8591 8-bit ADC used for battery voltage measurements. In order to use this I2C device add its name and address to I2C devices table and recompile kernel:
  arch/arm/mach-at91/board-sam9m10g45ek.c
  static struct i2c_board_info __initdata ek_i2c_devices[] = {
      ...
      {
          I2C_BOARD_INFO("pcf8591", 0x48),
      },
  };

Tochscreen

• Execute ts_calibrate in order to calibrate touchcreen.
• Add touchscreen settings export to /etc/profile:
  export TSLIB_TSDEVICE=/dev/input/event1
  export TSLIB_TSEVENTTYPE=INPUT
  export TSLIB_CONFFILE=/etc/ts.conf
  export TSLIB_CALIBFILE=/etc/pointercal
  export QWS_MOUSE_PROTO="Tslib:/dev/input/event1"

Hall speed sensor driver

• Build Hall speed driver module from https://github.com/bbogush/hall_speed.
• Copy hall_speed.ko to board's /home folder:
  sshpass -proot scp hall_speed.ko root@192.168.2.200:/home/hall_speed.ko
• Add "null::sysinit:/sbin/insmod /home/hall_speed.ko" to board's /etc/inittab file.

Ultrasonic distance sensor

• Build Ultrasonic HC-SR04 driver module from https://github.com/tanzilli/hc-sr04.
• Copy hcsr04.ko to the board:
  sshpass -proot scp hcsr04.ko root@192.168.2.200:/home/hcsr04.ko
• Add "null::sysinit:/sbin/insmod /home/hcsr04.ko" to board's /etc/inittab file.

WiFi AP

• Build TL-WN725N WiFi driver from https://github.com/lwfinger/rtl8188eu:
  make SUBARCH=arm CROSS_COMPILE=/usr/local/arm-2007q1/bin/arm-none-linux-gnueabi- KVER=2.6.30 KSRC=../../linux-2.6.30
• Copy 8188eu.ko to the board:
  sshpass -proot scp 8188eu.ko root@192.168.2.200:/home/8188eu.ko
• Add "null::sysinit:/sbin/insmod /home/8188eu.ko" to board's /etc/inittab file.
• Copy TL-WN725N firmware rtl8188eu-master/rtl8188eufw.bin to linux-2.6.30/firmware/rtlwifi/ folder, rebuild and flash kernel.
• Build hostapd from https://github.com/jenssegers/RTL8188-hostapd:
  make CC=/usr/local/arm-2007q1/bin/arm-none-linux-gnueabi-gcc DESTDIR=/home/bogdan/Development/buildroot-2013.05/output/target
• Copy hostapd to the board:
  sshpass -proot scp hostapd root@192.168.2.200:/sbin/hostapd
• Copy configuration files to the board:
  sshpass -proot scp platform/at91sam9g45-ekes/etc/hostapd.conf root@192.168.2.200:/etc/udhcpd.conf
  sshpass -proot scp platform/at91sam9g45-ekes/etc/init.d/S42udhcpd root@192.168.2.200:/etc/init.d/S42udhcpd
  sshpass -proot scp platform/at91sam9g45-ekes/etc/init.d/S41hostapd root@192.168.2.200:/etc/init.d/S41hostapd
  sshpass -proot scp platform/at91sam9g45-ekes/etc/hostapd.conf root@192.168.2.200:/etc/hostapd.conf
  sshpass -proot scp platform/at91sam9g45-ekes/etc/network/interfaces root@192.168.2.200:/etc/network/interfaces

Horn

• Copy horn sound file to the board:
  sshpass -proot scp platform/at91sam9g45-ekes/home/horn_signal.wav root@192.168.2.200:/home/horn_signal.wav

Schematic

The schematic is at platform/at91sam9g45-ekes/schematic/schematic.BMP. The prototype v1.0 has got some drawbacks, in particular:

• The board needs 12V input voltage, two batteries is not sufficient for stable 5V output.
• The BSS138 is low power FET. It is not fit for feeding LEDs directly.

Design

The Control application design:

Protocol

The communication protocol between applications is text based. Each packet contains null-terminated string. The string includes several commands in a row. Command structure is shown below: