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by jbeale
Thu Feb 15, 2018 8:48 pm
Forum: General discussion
Topic: Same code, compiler version, and HW. Different results
Replies: 30
Views: 890

Re: Same code, compiler version, and HW. Different results

Thanks- just updated my first post to add that Raspbian (gcc 6.3.0 20170516) also gives 45, so it's an oddity with MinGW32. I'll see if I can find a place to ask on some MinGW forum.
by jbeale
Thu Feb 15, 2018 7:35 pm
Forum: General discussion
Topic: Same code, compiler version, and HW. Different results
Replies: 30
Views: 890

Same code, compiler version, and HW. Different results

Just a curious note, not specific to RPi. I noticed that I get two different answers when running the same code (below) with the same compiler (gcc 6.3.0) on the same machine (Lenovo Thinkpad P71). The difference is that one is MinGW on Win10, and the other is Ubuntu 16.04 running in VirtualBox, but...
by jbeale
Tue Jan 30, 2018 7:22 pm
Forum: General discussion
Topic: how to tell apart two identical USB microphones?
Replies: 4
Views: 250

Re: how to tell apart two identical USB microphones?

Ok, that is useful; thank you! -john
by jbeale
Mon Jan 29, 2018 4:29 am
Forum: General discussion
Topic: how to tell apart two identical USB microphones?
Replies: 4
Views: 250

Re: how to tell apart two identical USB microphones?

Thanks for the tip! I do see my two USB audio devices, plus what I assume is the built-in SoC audio out. Not sure how to make use of this information to tell which is which, though. pi@rp4:~ $ ll /dev/snd/by-path/ total 0 lrwxrwxrwx 1 root root 12 Jan 28 20:19 platform-3f980000.usb-usb-0:1.3.4.3:1.0...
by jbeale
Mon Jan 29, 2018 2:08 am
Forum: General discussion
Topic: how to tell apart two identical USB microphones?
Replies: 4
Views: 250

how to tell apart two identical USB microphones?

I have two different "Behringer Line 2 USB" stereo audio input devices plugged into one RPi model 3. "lsusb" says in part: Bus 001 Device 007: ID 0d8c:0132 C-Media Electronics, Inc. Bus 001 Device 008: ID 0d8c:0132 C-Media Electronics, Inc. From "lsusb -v" I can see more information, but it looks li...
by jbeale
Sun Jan 28, 2018 7:30 pm
Forum: General discussion
Topic: Best plot software in my case?
Replies: 13
Views: 578

Re: Best plot software in my case?

Thanks for sharing the results, it is good to see how this could be used.
by jbeale
Fri Jan 26, 2018 7:49 pm
Forum: Other projects
Topic: earthquake sensing - Rasperry Shake and PS3 Eye webcam
Replies: 18
Views: 1231

Re: earthquake sensing - Rasperry Shake and PS3 Eye webcam

I have not been monitoring this thread and I don't routinely post my data here, but if you are interested, there is a website that plots locations of earthquakes detected by the "Raspberry Shake" sensors online in real time. http://raspberryshake.net/eqview/ There are now more than 500 such sensors ...
by jbeale
Fri Jan 26, 2018 7:14 pm
Forum: General discussion
Topic: Best plot software in my case?
Replies: 13
Views: 578

Re: Best plot software in my case?

This is a command-line plot program, but I've never used it, so I am not sure of dependencies:
http://ctioga2.sourceforge.net/
by jbeale
Tue Jan 16, 2018 9:06 pm
Forum: General discussion
Topic: How to implement Precision Time Protocol (PTP) on Rpi3 p2p network?
Replies: 3
Views: 1047

Re: How to implement Precision Time Protocol (PTP) on Rpi3 p2p network?

My understanding is that an R-Pi can get RMS timing jitter within 30 microseconds using the standard NTP system, assuming the NTP server is on the same LAN. See also: http://www.satsignal.eu/ntp/BBB-vs-RPi.html Is it possible to do any better with PTP without hardware timestamping, which I assume is...
by jbeale
Sat Jan 13, 2018 6:49 am
Forum: Bare metal
Topic: Timer with nanosecond accuracy for electronic purpose
Replies: 15
Views: 1043

Re: Timer with nanosecond accuracy for electronic purpose

I got a 20 nsec pulse from a GPIO pin driving a small VCSEL directly, just as a point of reference.
Here is the post: viewtopic.php?f=72&t=67741&start=25
by jbeale
Thu Jan 11, 2018 1:42 am
Forum: Beginners
Topic: Large gauge 15ft micro USB... Does it exist?
Replies: 5
Views: 260

Re: Large gauge 15ft micro USB... Does it exist?

Car dashcams have a similar requirement although most probably don't draw as much current as a RPi. So you might look for cables intended for that market, although most of them are only 10 to 13 feet long.
by jbeale
Wed Jan 10, 2018 3:27 pm
Forum: Other projects
Topic: earthquake sensing - Rasperry Shake and PS3 Eye webcam
Replies: 18
Views: 1231

Re: earthquake sensing - Rasperry Shake and PS3 Eye webcam

Yes. USGS puts the 7.6 Honduras quake at 02:51:31 UTC and I saw the signal arriving here in San Jose CA at 2:59:01 UTC with peak indicated frequency around 0.4 Hz but that's only due to the low-end rolloff in my sensor. It was a strong quake but also over 4000 km away from me, so the signal strength...
by jbeale
Tue Jan 09, 2018 10:56 pm
Forum: Other projects
Topic: earthquake sensing - Rasperry Shake and PS3 Eye webcam
Replies: 18
Views: 1231

Re: earthquake sensing - Rasperry Shake and PS3 Eye webcam

piezos would not be my first choice as they are nonlinear, high impedance, and subject to creep over time. Also mechanically fragile. I remember working with a piezo pressure sensor where the calibration would drift with humidity. However there are a large variety of DIY seismograph designs online, ...
by jbeale
Tue Jan 09, 2018 10:32 pm
Forum: Camera board
Topic: PiKrellCam: motion vector detect + OSD web interface
Replies: 1307
Views: 181273

Re: PiKrellCam: motion vector detect + OSD web interface

Please help. I want to upload my photos from pikrellcam to a google drive. Here is an article about Google Drive and Raspberry Pi: https://www.raspberrypi.org/forums/viewtopic.php?t=109587 Google Drive has various general-purpose API examples, here are some in Python: https://github.com/googledrive...
by jbeale
Thu Jan 04, 2018 6:22 pm
Forum: Camera board
Topic: PiKrellCam: motion vector detect + OSD web interface
Replies: 1307
Views: 181273

another use for the PS3 Eyecam audio recordings

Now that PiKrellCam does audio... in case of interest, here's something else you can do with continuous recordings from the PS3 Eyecam: https://www.raspberrypi.org/forums/viewtopic.php?f=41&t=201554#p1254333 the earthquake is obvious in the graphs, but the energy was sub-sonic (around 7 Hz) so it wa...
by jbeale
Thu Jan 04, 2018 6:18 pm
Forum: Other projects
Topic: earthquake sensing - Rasperry Shake and PS3 Eye webcam
Replies: 18
Views: 1231

earthquake sensing - Rasperry Shake and PS3 Eye webcam

I thought this was an interesting result. I have a Raspberry Shake seismometer sitting in my garage which records local earthquakes (and distant ones, if they are large enough). I also have another Pi connected to a Sony PS3 Eye webcam, which I'm using just as a microphone. It sits in a shed in the ...
by jbeale
Sat Dec 30, 2017 6:32 pm
Forum: Camera board
Topic: PiKrellCam: motion vector detect + OSD web interface
Replies: 1307
Views: 181273

Re: PiKrellCam: motion vector detect + OSD web interface

Is there any specially config needed or it is just a plug and play device? Just plug it in, and it works. For testing outside of PiKrellCam you can do this, it records 2-minute long MP3 files continually. ffmpeg -f alsa -ac 2 -ar 8000 -i plughw:1 -map 0:0 -acodec libmp3lame \ -b:a 96k -f segment -s...
by jbeale
Sat Dec 30, 2017 6:17 pm
Forum: Camera board
Topic: PiKrellCam: motion vector detect + OSD web interface
Replies: 1307
Views: 181273

Re: PiKrellCam: motion vector detect + OSD web interface

Have you any idea of power consumption as it's going to be on all the time I used a split USB cable with the data lines going to a RPi but +5V coming from an external supply. My lab power supply says the PS3 Eye device draws 110 mA at +5V. I also recorded and played back some audio to check it was ...
by jbeale
Fri Dec 29, 2017 3:54 am
Forum: Camera board
Topic: PiKrellCam: motion vector detect + OSD web interface
Replies: 1307
Views: 181273

Re: PiKrellCam: motion vector detect + OSD web interface

I got the 2 channel audio fixed up and audio can now be used as a motion event to trigger a recording. Thank you for doing this! I believe the PS3 Eye originally sold for quite a bit more; the current <$10 price may be a closeout (although it's been that way for at least a year now), anyway I recom...
by jbeale
Thu Dec 21, 2017 3:34 pm
Forum: Camera board
Topic: PiKrellCam: motion vector detect + OSD web interface
Replies: 1307
Views: 181273

Re: PiKrellCam: motion vector detect + OSD web interface

DaveDJ : Note, that microphone is stereo by itself, but the USB audio adaptor you linked to says only: "Mono microphone (optional)" so it will not give you a stereo input data stream through USB into the R-Pi. AFAIK there are no simple cheap audio input adaptors for stereo. There is only one stereo ...
by jbeale
Tue Dec 19, 2017 7:21 am
Forum: Camera board
Topic: PiKrellCam: motion vector detect + OSD web interface
Replies: 1307
Views: 181273

Re: PiKrellCam: motion vector detect + OSD web interface

I got a dual mic a while back but just haven't got around to looking into the 2 channel bug. Will try to get to it soon. No rush on that one, I'm probably the only guy who ever tried a stereo mic with it. Hope you have a great holiday season and thanks again for all the amazing work you've done on ...
by jbeale
Tue Dec 12, 2017 9:50 pm
Forum: Beginners
Topic: Raspberry Pi 3D mapping with radar
Replies: 14
Views: 8823

Re: Raspberry Pi 3D mapping with radar

the V1 version of the Lidar Lite had a buggy I2C implementation that would hang up at random times, and that was using Arduino-style microcontrollers that have repeatable timing at the microsecond level. See for example https://forum.pjrc.com/threads/28036-Translating-Lidar-Lite-I2C-example-to-Teens...
by jbeale
Mon Dec 11, 2017 6:35 pm
Forum: Camera board
Topic: PiKrellCam: motion vector detect + OSD web interface
Replies: 1307
Views: 181273

Re: PiKrellCam: motion vector detect + OSD web interface

Ah, I'd say it's probably not worth it then, if the camera must be restarted to change the parameters. Sounds like it would be better to have an entirely separate application to deal with audio-only recording. I have been entertaining some thoughts along those lines. Simply recording audio 24/7 is p...
by jbeale
Mon Dec 11, 2017 5:08 pm
Forum: Camera board
Topic: PiKrellCam: motion vector detect + OSD web interface
Replies: 1307
Views: 181273

Re: PiKrellCam: motion vector detect + OSD web interface

Would it be possible, in the event only an audio trigger starts the video, to temporarily select a lower frame rate and/or bitrate for the video recording? This would allow saving storage space in the case where audio events are less likely to result in interesting video. I'm not sure if changing fr...
by jbeale
Sat Dec 09, 2017 4:46 pm
Forum: The MagPi
Topic: AIY Projects Vision Kit Coming Soon!
Replies: 19
Views: 2236

Re: AIY Projects Vision Kit Coming Soon!

By the way, I have to say the full (not "tiny") YOLO network is pretty impressive, although very slow using only a CPU, not GPU. I'm using https://github.com/thtrieu/darkflow and here is an example of it correctly detecting four cars (some only partially visible) and most impressively the driver in ...

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