live sensor reading store in a data file

Question

i have a acceleration sensor which continuously outputs reading in 400 Hz ( like [0.21511 0.1451 0.2122] ). I want to store them and post process them. Now im able to store the first entry of the reading not all.

How to make it happen.

thanks

from altimu10v5.lsm6ds33 import LSM6DS33
from time import sleep
import numpy as np

lsm6ds33 = LSM6DS33()
lsm6ds33.enable()

accel=lsm6ds33.get_accelerometer_g_forces()

while True:


    DataOut = np.column_stack(accel)
    np.savetxt('output.dat',np.expand_dims(accel, axis=0),  fmt='%2.2f %2.2f %2.2f') 

sleep(1)

´

now i got the real problme. Just move this line into While loop : `accel=lsm6ds33.get_accelerometer_g_forces()` please see my updated answer — backtrack, Jun 07 '19 at 11:43

backtrack · Accepted Answer · 2019-06-07T11:41:12.220

0

Actual problem is, You are calling get_accelerometer_g_forces() only once. Just move it inside While looop

Updated:

while True:
    accel=lsm6ds33.get_accelerometer_g_forces()
    f=open('output.dat','ab')
    DataOut = np.column_stack(accel)
    np.savetxt(f,np.expand_dims(accel, axis=0),  fmt='%2.2f %2.2f %2.2f') 

sleep(1)

Here is a reference :How to write a numpy array to a csv file?

edited Jun 07 '19 at 11:41

answered Jun 07 '19 at 11:27

backtrack

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Closing the file fro time to time and appending it would be a good idea ineed, especially since there is not exit condition – user508402 Jun 07 '19 at 11:36
hi. result of this code returns same reading again and again in many times in data file. i want live changing readings like that . – saran Jun 07 '19 at 11:40
@user508402 - yup and yours is more python way – backtrack Jun 07 '19 at 11:40
gracious , @user508402 – saran Jun 07 '19 at 11:50
gracious @Backtrack – saran Jun 07 '19 at 11:50
`import calender import time ts = calendar.timegm(time.gmtime()) ` hei how can i add timestamp in this row. `np.savetxt(f,np.expand_dims(accel, axis=0), fmt='%2.2f %2.2f %2.2f') ` – saran Jun 07 '19 at 14:21

score 0 · Answer 2 · answered Jun 07 '19 at 11:34

Make sure that reading the data is enclosed within to loop!

You don't need numpy here yet:

while True:
    with open("output.dat", "w") as f:
        f.write("%.5f, %.5f, %.5f" % tuple(accelerometer_g_forces()))

Note that there is no condition to stop outputting the data.

live sensor reading store in a data file

2 Answers2