So what programming language to use? Well, turns out some guy who calls himself Topikachu has already made a ready Linux image with Python installed, and even made Python libraries to interface with the EV3 sensors and motors. Does it get any better than that? He’s made a quick howto on how to install it, which you can read on his github. If you have a USB Wifi dongle too (currently only one is supported, but I’m sure more will be added in time), it was very easy to get it hooked up on wifi too. I just had to log in over usb as described, update the wpa_supplicant.conf and I was good to go without a cable. You may want to check out what IP your brick received before unplugging the usb cable though

The Python API is really great, but I couldn’t find much documentation of it, so I had to read his code and look at his tests to figure out how to use it. Wasn’t too hard though, and here’s a little program I wrote just to test out that things were working (it doesn’t do much, basically just tries to crash :P)

#!/usr/bin/python

import time

from ev3.rawdevice import motordevice
from ev3.rawdevice import analogdevice
from ev3.rawdevice import uartdevice

from ev3 import lego

motordevice.open_device()
analogdevice.open_device()
uartdevice.open_device() 

A = 0x01
B = 0x02
C = 0x04
D = 0x08

right = A
left = D
both = A+D

touch = lego.EV3TouchSensor(0)
ir = lego.EV3IRSensor(3)
ir.set_prox_mode()

motordevice.speed(both,20)

distance = 101

while True:
  time.sleep(1)
  if touch.is_pressed() == 1:
    motordevice.stop(both, brake=1)
    print "stopping\n"
    break

  cur_distance = ir.get_distance()
  if cur_distance > distance:
    print "searching\n"
    motordevice.stop(both, brake=1)
    motordevice.speed(A, 20)
    time.sleep(1)
    motordevice.stop(A, brake=1)
    motordevice.speed(both,20)

  distance = cur_distance

motordevice.stop(both, brake=1)

That doesn’t look so hard, does it? Here’s some additional notes I made for myself to remember what the different functions do and how to use them.

Motors:
A = 0x01
B = 0x02
C = 0x04
D = 0x08
PORTS = A+B # Access both A and B at the same time
from ev3.rawdevice import motordevice
motordevice.open_device()

motordevice.speed(PORTS,20)
motordevice.stop(B,brake=1) # brake makes it actually brake the motor, not just stop turning it

from ev3.rawdevice import analogdevice
analogdevice.open_device()
touch = lego.EV3TouchSensor(0) # Note, the port numbering is 0-3, so the port marked 1 is 0, etc.
touch.is_pressed()

from ev3.rawdevice import uartdevice
uartdevice.open_device()
color = lego.EV3ColorSensor(3)
color.set_color_mode()
color.color_to_string() # This only works for color_mode
color.set_ref_raw_mode() # raw values, -127 -> 127
color.get_value() # raw value from sensor sensor

ir = lego.EV3IRSensor(2)
ir.set_prox_mode() # proximity mode
ir.get_distance() # for prox mode
ir.set_remote_mode() # for using the remote control
ir.get_remote_command() # get remote control command
ir.set_seek_mode() # follow remote control when button pressed
ir.get_all_direction_and_distance #  for seek mode
ir.get_direction_and_distance(chan) #  for seek mode

# This is how I managed to read info from a Hitechnic accelerometer sensor (originally made for the NXT)
from ev3 import robot
from ev3 import sensor
robot.open_all_devices()
iicsensor = IICSensor()
iicsensor = sensor.IICSensor(1, 0x02)
iicsensor.read(0x42)

Turns out installing a compatible VLC was a bit harder than expected. Of course, everything is usually a bit harder than expected when you run Gentoo Linux. After many reinstalls of different versions of VLC and gradually adding more USE flags, I finally found a combination that worked. Apparently, Knots uses a telnet interface in VLC that they have abandoned. In VLC 1.1.x it was still available with the format “oldtelnet” (which Knots supported using if configured to use with VLC 1.1.x), but no such luck with VLC 2.x. Maybe it’s still in there, I don’t know, but it must be under a different name if it is. So, in the unlikely event that somebody else out there is trying to use Knots in Gentoo Linux and is struggling with this, here is the final VLC install:
media-video/vlc-1.1.13 USE="X ffmpeg gcrypt httpd lua mmx mp3 ncurses ogg qt4 sqlite sse theora vlm vorbis xcb xml"
The USE flags of note here that I had to add for it to work are httpd, lua, xml and vlm.

After that, it was just a matter of getting my phone on the correct WLAN (for some reason, it kept choosing the one named “linksys” belonging to a neighbour :P), and turn off the silent profile on the phone (for some reason, Knots didn’t make i single sound when the phone was in the silent profile, even though the inbuilt music player couldn’t care less about that, oh well. Just caused me some confusion). I should maybe note, however, that even though Knots worked fine, it wasn’t as good as I’d hoped. A few features I missed were the possibility to just add everything to the playlist, and then shuffle said playlist. I had to settle for either the “random” feature, which just selected a (not very large) number of songs randomly from the library, or add some songs matching a search to a playlist, but then they couldn’t be shuffled. I just ended up using the “random” feature, and just go and select a new set of random songs every time it stopped.