Reliable application for accelerometers?
Clemens Dörrhöfer
cmd at gmx.net
Sun Dec 14 11:58:28 CET 2008
KaZeR wrote:
> Hi everyone.
>
> I'd need to be able to record accelerometers values and graph them later.
> The measure should last around 30 minutes.
>
> Can anyone recommend an application for that?
>
> Thanks in advance.
>
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the only thing you need to do is to pipe /dev/input/event2 or
/dev/input/event3 into a file. The analysis of the data can be done
later. You will get a lot of data though after 30 minutes.
This is a python script reading and evaluating the data. Its not mine. I
think I got it from the wiki somewhere.
Do a hexdump /dev/input/event3 to get an impression how much data we are
talking about first.
#!/usr/bin/python
import struct
from math import sqrt
x = 0
y = 0
z = 0
secondsensorfile = "/dev/input/event2"
#int, int, short, short, int
fmt = 'iihhi'
#open file in binary mode
in_file = open(secondsensorfile,"rb")
event = in_file.read(16)
while event:
(time1,time2, type, code, value) = \
struct.unpack(fmt,event)
time = time1 + time2 / 1000000.0
if type == 2:
if code == 0:
x = value
if code == 1:
y = value
if code == 2:
z = value
if type == 0 and code == 0:
sum = int(sqrt(x*x + y*y + z*z))
print x, y, z, sum
event = in_file.read(16)
in_file.close()
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