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by jbeale
Tue Sep 17, 2019 12:42 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Maximum length of ethernet cable between Raspberry Pi and camera
Replies: 8
Views: 231

Re: Maximum length of ethernet cable between Raspberry Pi and camera

In my use case with a thin HDMI cable, there was no interference, but then it was outdoors with no other signal sources anywhere around. If you have other cables or signal sources immediately adjacent, then I would expect some effects. Other things being equal, I would expect an HDMI cable to be les...
by jbeale
Mon Sep 16, 2019 7:23 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Maximum length of ethernet cable between Raspberry Pi and camera
Replies: 8
Views: 231

Re: Maximum length of ethernet cable between Raspberry Pi and camera

I'm aware of an adaptor for RPi camera extension using HDMI cable, which I have used. I used a very thin and flexible type of HDMI cable (only a few mm in diameter, and less than 1m long) and it worked. This version claims a 5 meter HDMI cable works: https://www.tindie.com/products/freto/pi-camera-h...
by jbeale
Fri Sep 13, 2019 2:16 pm
Forum: General discussion
Topic: 12v battery + 25 watt Solar = always powered 4B?
Replies: 17
Views: 519

Re: 12v battery + 25 watt Solar = always powered 4B?

I have used a "moteino" which is Arduino with RFM69HW radio module. Range is plenty good enough for me: "~540 meters range @38400kbps with lots of trees and one or two buildings inbetween." https://lowpowerlab.com/forum/rf-range-antennas-rfm69-library/rfm69hw-range-test!/ The same unit is also avail...
by jbeale
Fri Aug 30, 2019 2:50 pm
Forum: Graphics, sound and multimedia
Topic: sound of thunder / speaker test
Replies: 1
Views: 145

Re: sound of thunder / speaker test

BTW it turns out electret mics do not like high humidity and condensation, which we have plenty of in Oregon. The trick for outdoor recording use was to mount the mic on the small end of an exponential horn, padded with pillow stuffing to reduce airflow, all inside a wood box with spray foam insulat...
by jbeale
Fri Aug 30, 2019 2:19 pm
Forum: Graphics, sound and multimedia
Topic: sound of thunder / speaker test
Replies: 1
Views: 145

sound of thunder / speaker test

Just FYI... one of my R-Pi boards is under the roof eaves along the back of the house, recording ambient nature sounds. I am using a small-electret stereo microphone and preamp that I built, going into a Behringer Line2USB cable to the Pi. Last night there was some thunder along with the rain, which...
by jbeale
Fri Aug 23, 2019 3:31 pm
Forum: Off topic discussion
Topic: Best Raspberry Pi Alternatives 2019
Replies: 32
Views: 2537

Re: Best Raspberry Pi Alternatives 2019

> how successful it's been in introducing youngsters to computing?

My take: there is no one thing that magically makes many people interested in computing who didn't already have some interest. For those who are interested (of any age) the R-Pi is a great choice, and an unusually good value.
by jbeale
Fri Aug 23, 2019 5:00 am
Forum: Troubleshooting
Topic: ads1115 strange output
Replies: 2
Views: 109

Re: ads1115 strange output

I don't know any details of your setup, but what kind of electronics does your pH probe contain? In other words what does that BNC connect to, does it contain batteries or use external power? According to one vendor's datasheet https://www.analog.com/en/design-center/reference-designs/circuit-collec...
by jbeale
Sat Aug 17, 2019 7:05 pm
Forum: Camera board
Topic: PiKrellCam: motion vector detect + OSD web interface
Replies: 1460
Views: 316888

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: 1460
Views: 316888

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: 839

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: 92
Views: 61242

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: 1968

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: 1145

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: 292

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: 6809

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: 364

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: 373

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: 6809

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: 262

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: 12
Views: 1048

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: 316

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: 442

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: 997

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: 380

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: 414

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...

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