nxt-python錯誤：usb.core.NoBackendError

Question

我的系統上安裝了Python 2和Python 3。

我運行下面的腳本：

#!/usr/bin/env python 

import nxt.locator 
from nxt.motor import * 

def spin_around(b): 
    m_left = Motor(b, PORT_B) 
    m_left.turn(100, 360) 
    m_right = Motor(b, PORT_C) 
    m_right.turn(-100, 360) 

b = nxt.locator.find_one_brick() 
spin_around(b) 

與命令：它使用Python 2中，如預期python spin.py。

然而，當我運行此命令，我得到以下錯誤：

Traceback (most recent call last): 
    File "spin.py", line 12, in <module> 
    b = nxt.locator.find_one_brick() 
    File "/Library/Python/2.7/site-packages/nxt/locator.py", line 112, in find_one_brick 
    for s in find_bricks(host, name, silent, method): 
    File "/Library/Python/2.7/site-packages/nxt/locator.py", line 43, in find_bricks 
    for s in socks: 
    File "/Library/Python/2.7/site-packages/nxt/usbsock.py", line 84, in find_bricks 
    for bus in usb.busses(): 
    File "/Library/Python/2.7/site-packages/usb/legacy.py", line 353, in busses 
    sorted(core.find(find_all=True), key=lambda d: d.bus), 
    File "/Library/Python/2.7/site-packages/usb/core.py", line 1263, in find 
    raise NoBackendError('No backend available') 
usb.core.NoBackendError: No backend available 

當我運行此腳本通過USB我的NXT插入我的電腦，我的NXT上。另外，我已經安裝了pyUSB（正確的，我認爲）。

爲什麼會發生此錯誤？

Answer 1

解決方案是安裝libUSB。似乎pyUSB庫在後臺依賴於libUSB。

我與brew install libusb

安裝的libusb之後，該特定錯誤是固定的。