Program Lego Mindstorms EV3 in Python

Before you start

You need to have custom distribution. Prebuild image may not come with the latest version of ev3 module so make sure you follow instuction below to update it.

Quick start

Once you have a working environment, connect to EV3 brick and launch Python (executed on EV3RSTORM):

$ ssh root@10.0.1.1
root@python-ev3:~# python      
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import ev3
>>> ev3.open_all_devices()
>>> ev3.get_battery()
(6911.138911088911, 46.41822823641005, 0.0)
>>> ev3.set_led(ev3.LED_GREEN)
>>> ev3.close_all_devices()

Reading sensors:

>>> import ev3
>>> from ev3.sensor.lego import EV3TouchSensor
>>> ev3.open_all_devices()
>>> touch_sensor = EV3TouchSensor(ev3.SENSOR_1)
>>> while True:
...     if touch_sensor.is_pressed(): print "pressed"
... 
pressed    # I've pressed touch sensor
(ctrl+c to break the loop)

Documentation

Generated documentation available at readthedocs.org.

Troubleshooting

You may encounter the following problem:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/ev3/__init__.py", line 72, in open_all_devices
    analogdevice.open_device()
  File "/usr/local/lib/python2.7/dist-packages/ev3/rawdevice/analogdevice.py", line 16, in open_device
    _analogfile = os.open(lms2012.ANALOG_DEVICE_NAME, os.O_RDWR)
OSError: [Errno 2] No such file or directory: '/dev/lms_analog'

In such a situation please invoke:

# /etc/init.d/lms2012-driver.sh

Status

Some parts are still not implemented or lack high level API - pull requests are welcome.

Updating module on EV3 brick

Configuring key based authorisation. This step is required only once:

$ ssh root@10.0.1.1 mkdir -p .ssh
$ cat ~/.ssh/id_rsa.pub | ssh root@10.0.1.1 'cat >> .ssh/authorized_keys'

Whenever you want to update ev3 module just invoke:

$ ./update.sh

Note: this may take a while.