DMCC_Library

Fork to add native Python support to control the Dual Motor Controller Cape for the BeagleBone Black. We're using the fork and pull model, so hopefully these changes will be merged back into Exadler/DMCC_Library and this fork will be deleted.

Authors

Huge shout-out to Sarah Tan, Paul Tan and maybe others for building the hardware and original software. This repo is by the NCSU IEEE Robotics Team.

Open Hardware

All hardware is Open Source and can be found here (schematics, PCB, Eagle files).

Style

All Python code conforms to PEP8. Python docstrings are Sphinx-style. Please see PEP257 and this page for more docstring info.

Testing

All Python code should be thoroughly unit tested. To execute the tests, run python -m unittest discover from DMCC_Library/pyDMCC.

Motivation for Native Python Support

The original DMCC library is in C with Python bindings. As of Exadler/DMCC_Library@1d40b3a, it had performance issues that were prohibitive for actual use (see below). Additionally, The IEEE Robotics Team also doesn't need much of the functionally provided by the C code base, but does require code that's easy for new team members to understand, is well documented and clearly tested. We suspect other users have similar needs.

In [1]: import time

In [2]: import hardware.dmcc_motor as dm_mod              

In [3]: m01 = dm_mod.DMCCMotor(0, 1)

In [4]: m02 = dm_mod.DMCCMotor(0, 2)

In [5]: m11 = dm_mod.DMCCMotor(1, 1)

In [6]: m12 = dm_mod.DMCCMotor(1, 2)

In [7]: def move(speed, duration, front_left, front_right, back_left, back_right):
    m01.power = speed * front_left
    m02.power = speed * front_right
    m11.power = speed * back_left
    m12.power = speed * back_right
    time.sleep(duration)
    m01.power = 0
    m02.power = 0
    m11.power = 0
    m12.power = 0

In [8]: def timeit(func):                                                   
    start = time.time()
    func()
    elapsed = time.time() - start
    print "Time elapsed: {} s".format(elapsed)

In [9]: def move_zero():
    move(0, 0.01, 1, -1, 1, -1)  # set all motors to 0 power, wait 0.01 sec, turn them to 0 again

In [10]: timeit(move_zero)
Time elapsed: 3.22693610191 s

In [11]: timeit(move_zero)
Time elapsed: 3.22623682022 s

In [12]: timeit(move_zero)
Time elapsed: 3.22612094879 s