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Rakesh Pai edited this page Sep 19, 2017 · 6 revisions

Setup

This page documents the steps to get this app working on a AlphaBot.

Assembly

The official user guide and assembly guide do a good job of explaining how to assemble the chassis and sensors. At the moment, this app only uses the wheel encoders, and other sensors are ignored. You don't need to connect the other sensors. Their docs call the wheel encoder 'speed tester', which I guess it is, kinda.

The bot, as supplied, has its jumpers configured to route all signals to the Arduino. We aren't using an Arduino here, so you'll have to move them over to route signals to the Pi. The jumpers are yellow in colour, and are marked '22' in the manual on page 9. You'll have to ensure that they on the right side of the column of pins, and not on the left. So, the jumpers should short all the middle (signal) pins to the pins on right (Pi). If you don't do this, the Pi will still power up and work normally, but it won't be able to control any of the hardware on the bot.

Before you screw everything together, you might want to set up the Raspberry Pi first.

Prepare

This doc assumes:

  • You have a Raspberry Pi (3, preferably) with a recent copy of Raspbian.
  • Its WiFi is already connected to your network.
  • You have ssh access to it.

Installation takes time, so do the following in preparation:

  • Disconnect the Pi from the rest of the bot, and power it using wall power - a USB phone charger will do the job. Don't do the setup while powered using the supplied batteries. Batteries will be drained, its voltage will drop, the Pi will brownout, and your OS will end up in a weird corrupted state. Guess how I know.

  • During the install, it might be a good idea to connect the Pi to an ethernet cable to take advantage of any possible speed improvements. The installation process seems to download the entire Internet, so any speed improvement you can get is worth it.

Setup

  • Update everything. sudo apt-get update && sudo apt-get upgrade -y.

  • Optional, but recommended: Enable mDNS by installing avahi. mDNS will let you address your AlphaBot with a alphabot.local address, instead of using its IP address which can change frequently.

    • sudo apt-get install avahi-daemon.
    • Modify /etc/hostname to contain just alphabot, or use sudo raspi-config and modify the hostname. This is the hostname part of hostname.local, so feel free to add your flair.
    • Add a line to your /etc/hosts that says 127.0.1.1 alphabot. Substitute alphabot with the hostname you chose, if you chose a different one.

    If your dev machine is a Mac, you already have mDNS support on your machine. If you are using Windows or Linux, you might need to install software to use mDNS.

    If you do not want to set up mDNS, you might find it useful to set up a static IP in your router for your bot. The rest of this wiki assumes that you have mDNS configured. If you don't, substitute alphabot.local with the bot's IP address.

    (Ok, I didn't want to tell you, but since you insist - the hostname I've used for my bot is botty, short for Botty McBotface. I conducted an imaginary Internet poll, and Botty emerged as the most popular name. I decided to stick with it.)

  • Install node.js:

    curl -sL https://deb.nodesource.com/setup_8.x | sudo -E bash - # security warning, of course
sudo apt-get install nodejs

  • Install this app.

    wget https://github.com/rakeshpai/alphabot/archive/master.zip
unzip master.zip
rm master.zip
cd alphabot-master
npm install # This will take a while

  • Optional: Set up LIRC. This lets you control the bot using the supplied remote.

    • sudo apt-get install lirc liblircclient-dev
    • Edit /etc/modules to add the following lines: 
      lirc_dev
lirc_rpi gpio_in_pin=18
    • Edit your /boot/config.txt to add dtoverlay=lirc-rpi,gpio_in_pin=18
    • Modify /etc/lirc/hardware.conf to be as follows: 
      # /etc/lirc/hardware.conf
#
# Arguments which will be used when launching lircd
LIRCD_ARGS="--uinput"
 
# Don't start lircmd even if there seems to be a good config file
# START_LIRCMD=false
 
# Don't start irexec, even if a good config file seems to exist.
# START_IREXEC=false
 
# Try to load appropriate kernel modules
LOAD_MODULES=true
 
# Run "lircd --driver=help" for a list of supported drivers.
DRIVER="default"
# usually /dev/lirc0 is the correct setting for systems using udev
DEVICE="/dev/lirc0"
MODULES="lirc_rpi"
 
# Default configuration files for your hardware if any
LIRCD_CONF=""
LIRCMD_CONF=""
    • Replace /etc/lirc/lircd.conf with the following: 
      
# Please make this file available to others
# by sending it to <[email protected]>
#
# this config file was automatically generated
# using lirc-0.9.0-pre1(default) on Tue Sep 19 19:32:37 2017
#
# contributed by 
#
# brand:                       CARMP3
# model no. of remote control: 
# devices being controlled by this remote:
#

begin remote

  name  CARMP3
  bits           16
  flags SPACE_ENC|CONST_LENGTH
  eps            30
  aeps          100

  header       9102  4472
  one           617  1625
  zero          617   544
  ptrail        616
  repeat       9104  2204
  pre_data_bits   16
  pre_data       0xFF
  gap          108163
  toggle_bit_mask 0x0

      begin codes
          KEY_CHANNELDOWN          0xA25D
          KEY_CHANNEL              0x629D
          KEY_CHANNELUP            0xE21D
          KEY_PREVIOUS             0x22DD
          KEY_NEXT                 0x02FD
          KEY_PLAYPAUSE            0xC23D
          KEY_KPMINUS              0xE01F
          KEY_KPPLUS               0xA857
          KEY_FN                   0x906F
          KEY_0                    0x6897
          KEY_1                    0x30CF
          KEY_2                    0x18E7
          KEY_3                    0x7A85
          KEY_4                    0x10EF
          KEY_5                    0x38C7
          KEY_6                    0x5AA5
          KEY_7                    0x42BD
          KEY_8                    0x4AB5
          KEY_9                    0x52AD
          KEY_FN_1                 0x9867
          KEY_FN_2                 0xB04F
      end codes

end remote
    • Reboot the Pi. sudo shutdown -r 0.

That's it! Everything should be set up correctly.

To run the app, simply type in sudo npm start, and go to http://alphabot.local/ in your browser.

Development

This app already carries its development environment with it. All you need is an editor. You don't even need to run anything else. Just run the app as usual using sudo npm start and keep that running in a terminal. Then modify files as you please, and everything else Just WorksTM. Any necessary build steps are run automatically, the app is restarted automatically, and if you made UI changes, the browser is refreshed automatically.

The rest of this is optional, and is a matter of preference. You can skip this if you have some other way of working with remote files.

During development, I like to have the files available on my local machine (as opposed to lying on the Pi), so that I can use my preferred editor on my machine to modify files. I'm using Linux as my dev machine, so I use sshfs to mount the app folder from the Pi to my machine.

On my development machine, I type in the following:

mkdir alphabot
sshfs [email protected]:/home/pi/alphabot-master ./alphabot

This creates a local folder called alphabot, which is used as a mount point for the alphabot-master folder on the robot.

The remote folder is unmounted when the Pi is shutdown, or when you type in the following:

sudo fusermount -u alphabot

I'm sure similar solutions exist on Windows and Mac. Please feel free to update this doc with any steps you can provide.

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