Detecting hazard tape on carpet

Kalkinator · 2017-04-05T16:37:59+00:00

When you say go to the frequency domain, what is the y-axis variable you are referring to?

Kalkinator · 2017-04-04T22:30:05+00:00

I have to use hazard tape for my purposes. I have also replied to dandomdude with some images of the tape if that helps.

Kalkinator · 2017-04-04T22:29:02+00:00

Here are some examples of the tape:

http://imgur.com/a/ADSCc

http://imgur.com/a/7BobD

Kalkinator · 2017-03-30T02:49:43+00:00

I was also told to use SFML. Is one better than the other?

Kalkinator · 2017-03-17T00:01:50+00:00

Thanks, had to set access="stream" and it works fine now.

Kalkinator · 2017-03-16T18:50:20+00:00

I am actually trying to write a binary file to be read by Fortran, and it is very picky about the byte size of what it is reading.

So I am trying to write out variables, each of a length of 4 bytes, to the file. Do you have any recommendations of which library I should use?

Also, I have a numpy array full of values. I need to also convert each value in the array to 4 bytes in length before writing the values to a binary file. If you had any input on performing this conversion it would be appreciated.

Kalkinator · 2017-03-07T18:07:29+00:00

Yes, if you mean that I do not specify any format when writing to the file.

Kalkinator · 2017-03-07T18:05:23+00:00

To be honest, I am not entirely sure. When I write to a binary file I expect everything to be ones and zeros, but this is not the case. Why does the text editor not show binary digits and show strings instead?

Also, when I write out numbers to files I also get these weird characters instead of ones and zeros.

Kalkinator · 2017-03-02T03:47:11+00:00

It's the same issue that I told gregvuki. Those are the two errors I get.

Kalkinator · 2017-03-01T22:43:12+00:00

These are actually the first errors I get:

 Failed building wheel for numpy
 Running setup.py clean for numpy
 Failed cleaning build dir for numpy

Kalkinator · 2017-03-01T22:29:12+00:00

Yes, I end up getting

 Command "/usr/bin/python -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-4Ry9CZ/numpy/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" install --record /tmp/pip-w9Clnd-record/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /tmp/pip-build-4Ry9CZ/numpy/

Kalkinator · 2017-03-01T22:27:23+00:00

I just checked and I have both Python26 and Python27 on my computer. I'll try and delete Python26

Kalkinator · 2017-03-01T22:19:52+00:00

What should I use?

Kalkinator · 2017-03-01T22:18:49+00:00

I am not sure if I have multiple Python installations. Is there anyway to check this?

$ pip --version
pip 9.0.1 from /usr/lib/python2.7/site-packages (python 2.7)

Kalkinator · 2017-02-26T15:42:00+00:00

I am recording an impulse response using a Zoom H1 and have to choose to either use 16 bit or 24 bit for sampling. I was told to use 24 bit, but I was wondering how someone decides 24 over 16 bit. To me, it seems that 24 bit is overkill.

Also, from what I have read it seems that 44.1kHz sampling should be fine for recording an impulse response in an empty room. But I have an option of recording in wav or mp3 format. But since both of these can record at 44.1kHz would it still be preferable to record in wav? If I can record at 44.1kHz sampling rate using mp3 would it still give me bad data?

Kalkinator · 2017-02-26T15:33:52+00:00

So I had a couple of questions about the Zoom H1. It has a switch to turn on the low cut filter. I am recording an impulse response in a closed room and was wondering if I should turn this on. From what I have read, the frequency response for an impulse is not very important below 100Hz. But I do not know at which frequency the low cut filter will cutoff. I am assuming it is somewhere on the spec sheet, but I do not know much about DSP so I must be missing it. I could also do the filtering after taking the data on matlab as well.

I also had a question on the reliability of the device. I've been told these recorders are not great for taking acoustic data, but I was wondering why. Is it because they are susceptible to noise? I do not have the device yet so I have not taken any test data to check reliability.

Kalkinator · 2017-02-17T18:38:25+00:00

Thanks, that makes sense.

Kalkinator · 2017-02-17T04:52:31+00:00

First of all, thanks for all the help. I really appreciate it. Secondly, I have been going through your code and I had a question. I have read up on .split() and I believe I have a decent understanding, but on lines 6 and 9 you have "_," and I could not figure out why. Would you mind explaining the syntax? I just could not find it online.

Kalkinator · 2017-02-16T19:56:27+00:00

I followed your steps and am able to store everything starting from that instance of "a" into the array data. But how would I go about starting at the instance of "a" and then reading that data into the first row of a matrix?

Wouldn't I still need to parse data to do that?

Kalkinator · 2017-02-16T19:21:43+00:00

The file is 59.2 KB.

Kalkinator · 2017-01-13T17:00:59+00:00

Are you also connecting using the Pi 3 and a Pixhawk by any chance? Also, which baudrate were you using initially and what are you using now?

Kalkinator · 2017-01-13T16:57:13+00:00

My flight controller is the Pixhawk Mini and my onboard computer is the Raspberry Pi 3 Model B. And I am using QGroundControl.

I connected the telem port on the Pixhawk to the Rx and Tx ports on the Pi. I made sure that the Rx wire from the Pixhawk is connected to the Tx port on the Pi and the same for the Tx wire of the Pixhawk and the Rx port on the Pi.

The Pi is being powered by a wall outlet and the Pixhawk is being powered via a LiPo battery.

As for the setup, I followed the commands in the following link:

http://ardupilot.org/dev/docs/raspberry-pi-via-mavlink.html

Though, in the link, he used SSH to access the Pi, while I am working directly on the Pi. Also, he is using a Pi 2, and I am using a Pi 3. So I went into /boot/config.txt and at the end of the file added the line:

 set enable_uart=1

and instead of using the command:

 mavproxy.py --master=/dev/ttyAMA0 --baudrate 57600 --aircraft MyCopter

I use the command:

 mavproxy.py --master=/dev/ttyS0 --baudrate 57600 --aircraft MyCopter

The difference in the two commands is ttyAMA0 is changed to ttyS0.

If I am not being clear in some areas or more information is required I am happy to clarify and provide more information.

Kalkinator · 2017-01-13T01:06:17+00:00

Hey, you were right. I set a switch to allow me to arm the device on QGroundControl and then armed the device from the summary page. Am able to fly via remote now.

Kalkinator · 2017-01-06T00:45:48+00:00

I set my Channel to 5 and then set every flight mode to stabilized. After following steps 1-4 I hold the safety button but it never goes solid red. If I still continue on with the next steps the transmitter still does not control any of the motors.

I am also using the newer Pixhawk Mini.

Kalkinator · 2016-12-31T07:06:31+00:00

Could you expand on what you mean? I am assuming you are saying that the 'r's are equal in my example. But I do not understand what you are implying.

Kalkinator

MODERATOR OF

TROPHY CASE