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by jbeale
Wed May 08, 2019 12:08 am
Forum: Troubleshooting
Topic: my extern. DC-DC went bad (but R-Pi still OK!)
Replies: 0
Views: 95

my extern. DC-DC went bad (but R-Pi still OK!)

I just want to congratulate the R-Pi hardware designers for making a solid power supply circuit. I noticed a R-Pi 3 Model B v1.2 I had on my desk was quite warm when I accidentally touched the L1, L2 inductors near the power input. Then I measured the +5V GPIO and saw it was +7.1 V! :o I was powerin...
by jbeale
Mon Apr 15, 2019 2:26 am
Forum: General discussion
Topic: when after startup is the time correct?
Replies: 4
Views: 288

Re: when after startup is the time correct?

Thanks Silverlock. In my case it looks like I have different messages because I'm using 'chronyd' instead of NTP. Looks like I want to check for "Started Time & Date Service" given this syslog snippet: Apr 14 14:05:28 rp48 chronyd[419]: System clock wrong by 8.680650 seconds, adjustment started Apr ...
by jbeale
Sun Apr 14, 2019 9:02 pm
Forum: General discussion
Topic: when after startup is the time correct?
Replies: 4
Views: 288

when after startup is the time correct?

I want to start a process logging data on my R-Pi when it boots up. However, the data must be accurately stamped with the current time, which can only happen after the Pi has updated its clock from the network. If I run "timedatectl status" from either @reboot in crontab or the /etc/rc.local file an...
by jbeale
Mon Mar 25, 2019 6:57 pm
Forum: Camera board
Topic: Is global shutter available for camera module v2
Replies: 11
Views: 4531

Re: Is global shutter available for camera module v2

Well, an old thread resurfaces... neither the v1 nor the v2 RPi cameras have true gobal shutter. That would require an entirely different architecture which uses more silicon and costs more money. There was a datasheet for the v1 (OmniVision OV5647) chip marked "confidential/preliminary" that listed...
by jbeale
Sun Mar 17, 2019 4:26 am
Forum: Off topic discussion
Topic: Longest Raspberry Pi uptime
Replies: 71
Views: 49754

Re: Longest Raspberry Pi uptime

Mine is in the same place and has been going for a while now. It has been working on a distributed computing project. It also has two USB memory sticks, in case I wanted to store data on it remotely. As it turned out I didn't do that much, but both those sticks have now malfunctioned and cannot be w...
by jbeale
Sun Mar 03, 2019 5:24 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Waveshare High-Res ADC board (SPI) code
Replies: 3
Views: 681

Re: Waveshare High-Res ADC board (SPI) code

By the way, if you're testing ADC boards, here are two really useful programs: Kst2 (KST-Plot) is great for quickly plotting large CSV files (no problem with millions of points), and can even do filtering and plot frequency spectrum (FFT function). It reads a CSV file but can be "semi-real-time" as ...
by jbeale
Fri Mar 01, 2019 7:34 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Waveshare High-Res ADC board (SPI) code
Replies: 3
Views: 681

Re: Waveshare High-Res ADC board (SPI) code

Update: I am not as enthusiastic about this board as I was previously. It does "mostly" work, but running the PiPyADC python code overnight I see there was some SPI glitch (I presume) at some point that put the board in a strange mode. I wonder what happens if there is a Linux context-switch away fr...
by jbeale
Mon Feb 25, 2019 3:12 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Waveshare High-Res ADC board (SPI) code
Replies: 3
Views: 681

Waveshare High-Res ADC board (SPI) code

I noticed a "Waveshare High Precision AD/DA Board" board with an 8 channel 24-bit ADC, the TI ADS1256 on Amazon for a surprisingly reasonable price. The board also has some sort of DAC, which I didn't try. I see there have been various posts about it here. Waveshare has a wiki with a C code example,...
by jbeale
Thu Nov 15, 2018 2:57 am
Forum: Troubleshooting
Topic: Ethernet port stopped working
Replies: 2
Views: 322

Re: Ethernet port stopped working

Thanks for the reply. I did swap SD cards. It is not a software issue.
by jbeale
Wed Nov 14, 2018 4:48 am
Forum: Troubleshooting
Topic: Ethernet port stopped working
Replies: 2
Views: 322

Ethernet port stopped working

I have a Pi 3B (not 3B+) which had been working fine for about a month. It was remote and running headless, connected via ethernet jack and powered via external 48V->12V PoE module with a separate 12V -> 5V DC-DC converter. (I have made many such systems in the past, without issue.) I did "sudo halt...
by jbeale
Sat Nov 10, 2018 6:34 am
Forum: Graphics, sound and multimedia
Topic: better 180-degree view camera?
Replies: 2
Views: 1219

Re: better 180-degree view camera?

For anyone else curious- I've come to the conclusion that the Dahua IPC-EW4431-ASW (which is a 4MP standalone IP camera) is a worthwhile upgrade, in the ballpark of $120. It is not really a full-circle 180 fisheye, as the rectangular sensor crops off the image circle at top and bottom (Y), but it do...
by jbeale
Sat Nov 10, 2018 3:27 am
Forum: Graphics, sound and multimedia
Topic: better 180-degree view camera?
Replies: 2
Views: 1219

better 180-degree view camera?

Sorry this isn't specifically RPi-related but maybe someone knows. I have a 3rd-party camera board on a Pi which is (I presume) a OV5647 sensor with a fisheye lens. It sees around 170 degrees from edge to edge, and actually more than 180 degrees into the corners. Here is a picture of the module (sit...
by jbeale
Fri Nov 09, 2018 10:09 pm
Forum: Camera board
Topic: PiKrellCam: motion vector detect + OSD web interface
Replies: 1427
Views: 287228

script to trigger still & upload to weather site

I haven't kept current on this thread, so it's likely been done before- but anyway, in case it's helpful, here is a script I use to trigger PiKrellCam to take a still image every 5 minutes, resize, and upload it to a weather-camera site. I'm using a 3rd-party fisheye variant of the standard Pi camer...
by jbeale
Tue Nov 06, 2018 11:27 pm
Forum: General discussion
Topic: NASA 8k video from ISS
Replies: 4
Views: 490

Re: NASA 8k video from ISS

Sorry, I guess Google Photos doesn't allow direct links. Look at the video at 1:49 showing a blood draw, and check out the back wall around mid-frame.
by jbeale
Tue Nov 06, 2018 8:21 pm
Forum: General discussion
Topic: NASA 8k video from ISS
Replies: 4
Views: 490

NASA 8k video from ISS

Thought I saw something familiar on the wall in the background of the 8K resolution video https://www.youtube.com/watch?v=7k2uKb9vCOI from ISS that NASA released recently...

Image
by jbeale
Fri Aug 24, 2018 9:12 pm
Forum: Troubleshooting
Topic: RPi Zero USB OTG (usb-ethernet device)
Replies: 0
Views: 1273

RPi Zero USB OTG (usb-ethernet device)

I'm trying to use my Raspberry Pi Zero V1.2 with current Raspbian Lite: Linux rp01 4.14.50+ #1122 Tue Jun 19 12:21:21 BST 2018 armv6l GNU/Linux in the USB OTG ("usb gadget") mode, to appear as a USB-Ethernet device to another PC (in this case, a MiniPC running Ubuntu 18.04.1). Following an online tu...
by jbeale
Mon Aug 20, 2018 6:43 pm
Forum: Beginners
Topic: measure height elevation
Replies: 5
Views: 471

Re: measure height elevation

There are pressure sensors that do have a few cm height resolution, for example, Honeywell makes this differential pressure sensor: https://www.digikey.com/product-detail/en/honeywell-sensing-and-productivity-solutions/HSCMRRD2.5MDSA3/HSCMRRD2.5MDSA3-ND/3935154 its claimed *accuracy* is 0.25% full s...
by jbeale
Mon Aug 20, 2018 4:07 pm
Forum: General discussion
Topic: surprising result after applying +12V to +5Vin
Replies: 5
Views: 834

Re: surprising result after applying +12V to +5Vin

That's a neat story (at least the first part). Seems like your Pi had a real mechanical circuit breaker!
Yes, my downfall was soldering on the same kind of generic 5.5/2.1 mm DC power jack as I use for +12V, and then being in a hurry and careless about connections.
by jbeale
Mon Aug 20, 2018 4:20 am
Forum: General discussion
Topic: surprising result after applying +12V to +5Vin
Replies: 5
Views: 834

Re: surprising result after applying +12V to +5Vin

I was not speaking of the onboard audio output, but a third-party external USB-audio adapter which I was using for a mic input. Quite a flimsy and cheap one too, I think it was under $5 from ebay. The USB port provides +5V output, so I did not expect it to be much different than the board's own +5V ...
by jbeale
Mon Aug 20, 2018 2:05 am
Forum: General discussion
Topic: surprising result after applying +12V to +5Vin
Replies: 5
Views: 834

surprising result after applying +12V to +5Vin

I did a dumb thing today to a RPi 3B, applying +12V directly from a 14 Ah battery to the +5V / GND GPIO pins (and in fact it was through a good soldered connection, not just spring contact wires). Unsurprisingly there was small jet of flame from the PCB, as this battery can probably deliver 50 A in ...
by jbeale
Wed Aug 15, 2018 4:34 am
Forum: Networking and servers
Topic: USB networking for secure file sharing
Replies: 11
Views: 871

Re: USB networking for secure file sharing

In case you were puzzled why anyone would want this, the use case is a Windows PC that has a tested software system and changing any of the application software is difficult. However purely windows-OS-level changes such as permissions on a shared folder (and installing the Ethernet-over-USB driver) ...
by jbeale
Mon Aug 13, 2018 4:42 pm
Forum: Networking and servers
Topic: USB networking for secure file sharing
Replies: 11
Views: 871

USB networking for secure file sharing

I know it is possible to read a shared folder on a Windows PC from a remote Pi over the network using SAMBA. I understand the RPi Model A+ and also the Zero and Zero+W can work in "USB Gadget" mode (eg. USB device, not host). Also that there exist drivers to make it possible to do TCP/IP over USB as...
by jbeale
Fri Aug 10, 2018 6:05 pm
Forum: Troubleshooting
Topic: software shutdown and LED blinking
Replies: 2
Views: 272

Re: software shutdown and LED blinking

"As soon as the ten winks are done you can safely pull the power."

Ok. It sounds like I should wait for it to be completely done blinking then.
Apparently I've just been lucky all those times before that I didn't wait, and did not have SD card damage?
by jbeale
Fri Aug 10, 2018 5:41 pm
Forum: Troubleshooting
Topic: software shutdown and LED blinking
Replies: 2
Views: 272

software shutdown and LED blinking

When I do a software-directed shutdown of my Raspberry Pi, the activity LED blinks at a fixed rate for a while, then stops. Is it safe to remove power when it is doing this final blink pattern, or is it in fact still writing to the SD card during that time? Reason I ask is that I am using a RPi-powe...
by jbeale
Wed Jul 25, 2018 11:06 pm
Forum: Camera board
Topic: wider Hfov lens for 5mp camera module
Replies: 4
Views: 585

Re: wider Hfov lens for 5mp camera module

I realize there isn't much info here, but: https://elinux.org/Rpi_Camera_Module#Replacing_Stock_Lens As far as I know there is no drop-in replacement for the tiny (non-standard, M6 ?) lens used in the camera module. Easiest thing to do is simply add an external wide-angle adaptor such as are sold fo...

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