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by jbeale
Sat Aug 17, 2019 7:05 pm
Forum: Camera board
Topic: PiKrellCam: motion vector detect + OSD web interface
Replies: 1453
Views: 306312

Re: PiKrellCam: motion vector detect + OSD web interface

I had not paid much attention to how all this works, but I think at least on my system that the entire day's videos are simply moved to the archive folder around midnight. I was doing those experiments right around midnight, so the process of archiving may have just happened. At least on my system, ...
by jbeale
Sat Aug 17, 2019 7:07 am
Forum: Camera board
Topic: PiKrellCam: motion vector detect + OSD web interface
Replies: 1453
Views: 306312

Re: PiKrellCam: motion vector detect + OSD web interface

I have a few Pi's running PiKrellcam v4.2.1. In addition to motion capture, it takes a still photo every other hour. The still images are triggered by this line in my crontab: # take one still photo every other hour 7am-5pm 0 7-17/2 * * * echo "still" > /home/pi/pikrellcam/www/FIFO PiKrellCam also d...
by jbeale
Thu Aug 15, 2019 3:31 pm
Forum: Troubleshooting
Topic: Four dead Pis in one class!?
Replies: 15
Views: 479

Re: Four dead Pis in one class!?

It is true that using the Micro-USB power input is safer than trying to connect +5V directly to the GPIO pins, where there's one way to do it right and lots of ways to immediately smoke the Pi. However that is a completely separate issue from whether you are using two physically separate battery pac...
by jbeale
Thu Aug 15, 2019 2:17 pm
Forum: Off topic discussion
Topic: Longest Raspberry Pi uptime
Replies: 90
Views: 53745

Re: Longest Raspberry Pi uptime

I get an "uptime" status email every day from my Pi2B hosted in a data center. It has been running a BOINC client for some time now:

Sent: 14 Aug '19 10:57
11:57:02 up 2096 days, 18:47, 0 users, load average: 1.12, 1.11, 1.13
by jbeale
Thu Aug 08, 2019 9:23 pm
Forum: General discussion
Topic: To the Raspberry Zero Production line...
Replies: 41
Views: 1533

Re: To the Raspberry Zero Production line...

FWIW: 2.5 mm standoffs in black nylon https://www.amazon.com/Female-Standoff-Assortment-Motherboard-Raspberry/dp/B07D5T1TXV/ 240 pieces for $10 so that's not a whole lot of expense per Pi board. AFAIK the original PCB holes were only intended to mate with dowel pins for test fixturing at the factory...
by jbeale
Thu Aug 08, 2019 7:42 pm
Forum: General discussion
Topic: YouTube on Raspberry Pi 4 Choppy!!
Replies: 14
Views: 719

Re: YouTube on Raspberry Pi 4 Choppy!!

I have not used it, but my understanding was a dedicated media player (LibreElec / Kodi) running on the RPi4 can play 1080p video smoothly. It looks like Kodi has a plug-in so that it can play video from YouTube directly, although it may be tricky to setup. https://forum.kodi.tv/
by jbeale
Tue Aug 06, 2019 10:12 pm
Forum: General discussion
Topic: Pi 4 wi-fi cutting out with an audible chirping noise
Replies: 5
Views: 213

Re: Pi 4 wi-fi cutting out with an audible chirping noise

I don't have a Pi 4 myself, and I've never had this problem on a Pi. However, in general I can tell you that "chirping" can happen when a switch-mode power supply frequency swings through the audible range in response to a changing load, or a changing input voltage. All the recent Pi models include ...
by jbeale
Tue Aug 06, 2019 1:50 am
Forum: General discussion
Topic: 4gb - 4B Demand must be high.
Replies: 134
Views: 5942

Re: 4gb - 4B Demand must be high.

Imperf3kt wrote:
Mon Aug 05, 2019 10:13 pm
As someone with over 3000 tabs open across multiple devices,
Well, I learn something new every day. I'm typing this on a Chromebook shared by 4 people and it seldom exceeds 10 open tabs. I guess everyone has their own way of managing things!
by jbeale
Sun Aug 04, 2019 5:51 am
Forum: Automation, sensing and robotics
Topic: Which Raspbery Pi for agricultur IoT to use
Replies: 4
Views: 240

Re: Which Raspbery Pi for agricultur IoT to use

The kind of sensors you mention are fairly low-speed, things like temperature and wind speed probably don't need more than one reading per second. Any of the RPi models should be fine for that. The recent models (Pi3, Pi4, Pi Zero W) all have wifi built-in, and the full sized boards have Ethernet as...
by jbeale
Sun Aug 04, 2019 5:46 am
Forum: Beginners
Topic: What is the shiny part on RPI4 (above the raspberry) for?
Replies: 6
Views: 306

Re: What is the shiny part on RPI4 (above the raspberry) for?

... there are tuned antennas inside... Just to be pedantic, there may be tuned RF circuits inside the can but the antenna is just outside it, a V-shaped pattern between the can and the board edge, made from etched copper areas on the PCB. The RF doesn't go through the top of the metal shield can, b...
by jbeale
Sat Aug 03, 2019 2:22 am
Forum: General discussion
Topic: 4gb - 4B Demand must be high.
Replies: 134
Views: 5942

Re: 4gb - 4B Demand must be high.

There's obviously faster things out there. It is my impression, and I think a common one, that nothing touches the price/performance ratio of a Pi (any of them), and moreover it's hard to beat the support and the community at any price. At least once a month my email announces a new "pi killer" but ...
by jbeale
Fri Aug 02, 2019 6:19 pm
Forum: Python
Topic: Tensorflow is too slow
Replies: 3
Views: 150

Re: Tensorflow is too slow

Simply doing import tensorflow as tf is pretty slow even on a normal PC in my experience, so it's not just the Pi. I presume that is loading and configuring a large amount of code as well as the whole Keras framework etc. whether or not your following Python code actually uses any of that. Since pyt...
by jbeale
Wed Jul 31, 2019 2:00 pm
Forum: Troubleshooting
Topic: Raspberry Pi 4 green light of death
Replies: 10
Views: 646

Re: Raspberry Pi 4 green light of death

I am not a RPi Engineer, so I should not even respond. But... "Both the red and the green light flashed four times, with a short but noticeable fade out after each light-up" if there is an actual fade-out of the LED, I think that can only happen two ways: 1) high frequency PWM drive with smoothly ch...
by jbeale
Tue Jul 30, 2019 4:07 am
Forum: Beginners
Topic: RPi4 just arrived! Excitedly I open the box, and...
Replies: 2
Views: 285

Re: RPi4 just arrived! Excitedly I open the box, and...

From what I can see in the photo, that does not look it would meet the IPC standards for PCB soldering that I remember.
I can't quite tell but if it's just flux residue, it might actually still work ok. If there is any solder bridging between pins, of course that is bad and will not work.
by jbeale
Mon Jul 29, 2019 6:02 am
Forum: Troubleshooting
Topic: Found a RPi2 while cleaning out, however it does not boot!
Replies: 10
Views: 357

Re: Found a RPi2 while cleaning out, however it does not boot!

I just totally changed my reply, because I believe the photo of the board in the test point link you provide may be a R-Pi 3 (?) Just be sure which model Pi you are trying to use; by now I have forgotten how many different Pi varieties there are. I checked one under my desk that I thought at first w...
by jbeale
Sun Jul 28, 2019 9:51 pm
Forum: General discussion
Topic: Next pi zero and PoE
Replies: 28
Views: 802

Re: Next pi zero and PoE

The active PoE splitters (meaning it includes a DC-DC converter for 48V -> 5V) that I've seen are all the same size, a rectangular box that is a bit larger around than a RJ45 jack, and 8 cm or 3-1/4" long plus the cables. I've used them to power various Pi devices including a Pi Zero and yes, it was...
by jbeale
Sun Jul 28, 2019 8:44 pm
Forum: General discussion
Topic: what is faster on rpi3b Chromium r70 or flintos v.03
Replies: 11
Views: 271

Re: what is faster on rpi3b Chromium r70 or flintos v.03

from the FydeOS website https://fydeos.com/
"... for Chinese students... also complete with ancillary facilities to help managers easily monitor user behavior."
at least they are upfront about it, I guess.
by jbeale
Sun Jul 28, 2019 2:59 pm
Forum: Other projects
Topic: Raspberry pi Underwater case min. 40m deep
Replies: 5
Views: 249

Re: Raspberry pi Underwater case min. 40m deep

You can get an iphone case rated that deep for under $100. It is too thin to fit any Pi with a ethernet jack, but a Pi Zero would fit. Of course you'd need to figure out what battery would also fit. I don't know about a display. https://www.amazon.com/HAWEEL-Underwater-Professional-Swimming-Snorkeli...
by jbeale
Sun Jul 28, 2019 5:15 am
Forum: Advanced users
Topic: Need Help Installing Tensorflow Lite
Replies: 3
Views: 599

Re: Need Help Installing Tensorflow Lite

I have not tried it, but apparently based on https://www.raspberrypi.org/magpi/tensorflow-ai-raspberry-pi/ you can simply do: sudo apt install libatlas-base-dev pip3 install tensorflow one of the comments to the above suggests you want to make sure you're using the latest pip3 etc. first: sudo pip3 ...
by jbeale
Sat Jul 27, 2019 6:21 pm
Forum: Beginners
Topic: Battery Usage Pi Zero W for video stream
Replies: 5
Views: 132

Re: Battery Usage Pi Zero W for video stream

What drgeoff said is correct. Just to beat a dead horse further, as the OP mentioned the CR2032 type of coin cell, here's a datasheet: http://data.energizer.com/pdfs/cr2032.pdf That looks like about 2.9V and 235 mAh assuming a 15K ohm load. The cell's internal resistance starts near 10 ohms when fre...
by jbeale
Sat Jul 27, 2019 5:26 pm
Forum: Beginners
Topic: Battery Usage Pi Zero W for video stream
Replies: 5
Views: 132

Re: Battery Usage Pi Zero W for video stream

According to the current draw chart at https://raspi.tv/2016/raspberry-pi-zero-1-3-power-usage-with-camera the Pi Zero draws 240 mA while recording 1080p video. They don't mention also using wifi to stream the data, so that will probably use somewhat more, let's say it becomes 300 mA. To run 3 hours...
by jbeale
Fri Jul 26, 2019 3:31 am
Forum: General discussion
Topic: I would like to run the Raspberry Pi 4 module with windows 10 OS
Replies: 16
Views: 848

Re: Raspberry PI works with Windows 10 OS

It would be helpful to change the title of this thread, which I suppose was intended as an aspirational goal, but literally it seems a misleading assertion.
by jbeale
Thu Jul 25, 2019 7:43 pm
Forum: Troubleshooting
Topic: Pi4 - Max USB current
Replies: 5
Views: 200

Re: Pi4 - Max USB current

I know at least some drives draw about 3x the normal running power at start while spinning up the disk. Another advantage of SSD. Search on "HDD startup current" for more info.
by jbeale
Thu Jul 25, 2019 2:35 pm
Forum: Troubleshooting
Topic: Raspberry Pi 4 Not Enough Power to Boot?
Replies: 13
Views: 469

Re: Raspberry Pi 4 Not Enough Power to Boot?

Here's an example of measuring the startup current draw of a hard drive, a kind that uses +12V and +5 V. The current draw from the 12V supply near the beginning was about three times the steady-state current, due to the motor draw while spinning up the discs from standstill. http://45drives.blogspot...
by jbeale
Wed Jul 24, 2019 5:38 am
Forum: General discussion
Topic: Raspberry Pi as keylogger
Replies: 9
Views: 482

Re: Raspberry Pi as keylogger

I'm somehow reminded of a first post to an electronics forum asking (an "urgent request" actually) the best way to rig a microwave remotely to turn on long enough to ignite a can of gasoline. In reply to skeptical queries, he insisted "of course" this was only for private experimental purposes.

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