1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
|
#Copyright (c) 2011, 2012, Ian Daniher
#Copyright (c) 2012, Tony Forster, Walter Bender
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
import sys
import os
sys.path.append(os.path.dirname(__file__))
import usb.core
import logging
TILT_FORWARD = 0
TILT_LEFT = 1
TILT_RIGHT = 2
TILT_BACK = 3
NO_TILT = -1
class WeDo:
def __init__(self):
"""Find a USB device with the VID and PID of the Lego
WeDo. If the HID kernel driver is active, detatch
it."""
self.dev = usb.core.find(idVendor=0x0694, idProduct=0x0003)
if self.dev is None:
logging.debug("No Lego WeDo found")
else:
if self.dev.is_kernel_driver_active(0):
try:
self.dev.detach_kernel_driver(0)
except usb.core.USBError as e:
sys.exit("Could not detatch kernel driver: %s" % str(e))
self.valMotorA = 0
self.valMotorB = 0
def getRawData(self):
"""Read 64 bytes from the WeDo's endpoint, but only
return the last eight."""
self.endpoint = self.dev[0][(0,0)][0]
data = list(self.endpoint.read(64)[-8:])
return data
def processMotorValues(self, value):
"""Check to make sure motor values are sane."""
retValue = int(value)
if 0 < value < 101:
retValue += 27
elif -101 < value < 0:
retValue -= 27
elif value == 0:
retValue = 0
return retValue
def setMotors(self, valMotorA, valMotorB):
"""Arguments should be in form of a number between 0
and 100, positive or negative. Magic numbers used for
the ctrl_transfer derived from sniffing USB coms."""
if self.dev is None:
return
self.valMotorA = self.processMotorValues(valMotorA)
self.valMotorB = self.processMotorValues(valMotorB)
data = [64, self.valMotorA&0xFF,
self.valMotorB&0xFF, 0x00, 0x00, 0x00, 0x00, 0x00]
self.dev.ctrl_transfer(bmRequestType = 0x21, bRequest = 0x09,
wValue = 0x0200, wIndex = 0,
data_or_wLength = data)
def getData(self):
"""Sensor data is contained in the 2nd and 4th byte,
with sensor IDs being contained in the 3rd and 5th
byte respectively."""
rawData = self.getRawData()
sensorData = {rawData[3]: rawData[2], rawData[5]: rawData[4]}
return sensorData
def processTilt(self, v):
"""Use a series of elif/value-checks to process the
tilt sensor data."""
if v in [24, 25, 26, 27]:
return TILT_BACK
elif v in [73, 74, 75, 76]:
return TILT_RIGHT
elif v in [175, 176, 177, 178, 179, 180]:
return TILT_FORWARD
elif v in [229, 230]:
return TILT_LEFT
else:
return NO_TILT
def interpretData(self):
"""This function contains all the magic-number
sensor/actuator IDs. It returns a list containing one
or two tuples of the form (name, value)."""
data = self.getData()
response = []
for num in data.keys():
if num in [0, 1, 2]:
response.append(('motor', 1))
elif num in [176, 177, 178, 179]:
response.append(('distance', data[num]-69))
elif num in [38, 39]:
response.append(('tilt', self.processTilt(
data[num])))
elif num in [238, 239]:
response.append(('motor', 0))
elif num in [228, 230]:
response.append(('normal', 1))
return response
def getTilt(self):
if self.dev is None:
return NO_TILT
data = self.getData()
for num in data.keys():
if num in [38, 39]:
return self.processTilt(data[num])
return NO_TILT
def getDistance(self):
if self.dev is None:
return 0
data = self.getData()
for num in data.keys():
if num in [176, 177, 178, 179]:
return data[num] - 69
return 0
def setMotorA(self, valMotorA):
self.setMotors(valMotorA, self.valMotorB)
def setMotorB(self, valMotorB):
self.setMotors(self.valMotorA, valMotorB)
def getMotorA(self):
if self.dev is None:
return 0
return self.valMotorA
def getMotorB(self):
if self.dev is None:
return 0
return self.valMotorB
|
