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by davidcoton
Mon Jun 18, 2018 8:13 pm
Forum: Troubleshooting
Topic: [Resolved] Electrical noise if ethernet is connected.
Replies: 9
Views: 199

Re: Electrical noise if ethernet is connected.

The Traveler wrote:
Mon Jun 18, 2018 8:07 pm
That one shouldn't matter. The Pi Ethernet port is autosensing.
Yes, but I usually mention it just to eliminate it early as it does occasionally happen.

Cheers.
It doesn't matter. A crossover cable will still work, in the absence of other problems. That's what autosensing does.
by davidcoton
Mon Jun 18, 2018 7:47 pm
Forum: Troubleshooting
Topic: [Resolved] Electrical noise if ethernet is connected.
Replies: 9
Views: 199

Re: Electrical noise if ethernet is connected.

The Traveler wrote:
Mon Jun 18, 2018 3:38 pm
Be sure you're not using a cross-over cable as well. It's easy to mistake them without being clearly marked or examining the RJ-45 ends. It happens.
That one shouldn't matter. The Pi Ethernet port is autosensing.
by davidcoton
Sat Jun 16, 2018 9:09 pm
Forum: General discussion
Topic: Generating smoke from a Pi Zero
Replies: 15
Views: 437

Re: Generating smoke from a Pi Zero

But there are no data connections to the Power socket. My guess is that a short from either stray metal on the board or a component failure led to enough current (the Pi0W having no polyfuse) to damage the cable -- most likely at a connection to the plug. However it is unusual (in my experience) to ...
by davidcoton
Fri Jun 15, 2018 10:42 pm
Forum: Troubleshooting
Topic: raspberry pi 3 b+ Rainbow screen
Replies: 4
Views: 160

Re: raspberry pi 3 b+ Rainbow screen

Okay, that narrows things down a bit. I can think of three possibilities: Fault in writing to the SDCard. What hardware did you use to write the SDCard? Is it SDHC compatible? SDCard itself is faulty. Have you checked it? Do you know anyone else with a Pi who could check it for you? Pi is faulty (Un...
by davidcoton
Fri Jun 15, 2018 8:49 pm
Forum: Troubleshooting
Topic: raspberry pi 3 b+ Rainbow screen
Replies: 4
Views: 160

Re: raspberry pi 3 b+ Rainbow screen

Where did NOOBS and Raspbian come from? What is the package date?

What are the Pi's red PoWeR and green ACTivity lights doing? If flashing, random or a regular pattern? What pattern (they have meanings)?
by davidcoton
Thu Jun 14, 2018 9:44 pm
Forum: General discussion
Topic: Forum Shuffle
Replies: 29
Views: 1187

Re: Forum Shuffle

Could we have a separate section for "How-Tos" and similar tutorials, and the bile that sometimes goes with them?( See this.)
Positively, it would make it much easier to find tutorials.
Negatively, it would make it much easier to ignore the angst.
by davidcoton
Thu Jun 14, 2018 5:15 pm
Forum: Troubleshooting
Topic: Whistling sound from speakers on connecting USB mouse
Replies: 11
Views: 392

Re: Whistling sound from speakers on connecting USB mouse

Check the 5V rail first, probably easiest on a 5V GPIO pin (TAKE CARE -- don't short anything with the probe).
Look for ripple at several kHz (corresponding to the whistle pitch).
Use AC coupling so you can observe the comparatively small ripple on top of 5V DC.
by davidcoton
Wed Jun 13, 2018 10:59 pm
Forum: Beginners
Topic: Doubt with raspberry pi battery
Replies: 1
Views: 94

Re: Dude with Battery for raspberry pi 3

It might work if you have nothing much connected to the USB and drawing power. 1.5A is below the 2A minimum recommended for a Pi3B (Pi PSU is 2.5A, Pi3B+ has that as its minimum recommended supply). You will need good (thick, short) wires from battery to Pi. Off charge, it will last about an hour. T...
by davidcoton
Wed Jun 13, 2018 10:48 pm
Forum: Troubleshooting
Topic: red light blink
Replies: 3
Views: 108

Re: red light blink

It means the 5V power supply is going below 4.65V. Either the PSU is inadequate, or the cable from PSU to Pi is too long or thin, or something else is loosing volts along the way.

Which model Pi?
What is connected to it (anything on HDMI, USB, or GPIO)?
What is the PSU spec (V and A)?
by davidcoton
Wed Jun 13, 2018 10:42 pm
Forum: Beginners
Topic: Raspian broke after editing just one file?
Replies: 3
Views: 163

Re: Raspian broke after editing just one file?

Basically, you are following an out-of-date tutorial. Though editing that file should not prevent booting. So that someone can give better answers than that tutorial, can you give more information: What model Pi? What OS? With NOOBS (or PINN) or without? What PSU? What else is connected and how? (Sc...
by davidcoton
Wed Jun 13, 2018 9:30 pm
Forum: Troubleshooting
Topic: Whistling sound from speakers on connecting USB mouse
Replies: 11
Views: 392

Re: Whistling sound from speakers on connecting USB mouse

They are getting power from the same supply, not the Pi USB. I did try separate power supplies, it does get rid of the high pitched ring but there is still noise in the speakers. The issue is I need to power the project from a single supply. I'm also using a 5V 10A supply. This should be more than ...
by davidcoton
Wed Jun 13, 2018 8:55 pm
Forum: General discussion
Topic: What is configuration of wiring connection use db9 serial port from output device to RPi 3 by IDC10 head connector
Replies: 5
Views: 190

Re: What is configuration of wiring connection use db9 serial port from output device to RPi 3 by IDC10 head connector

mark3112 wrote:
Wed Jun 13, 2018 7:40 pm
Try a search on the phrase

Ultra Compact RS232 to TTL Converter with Male DB9

and you will probably want some conection leads to connect it to the header.
If you buy a converter, make sure it uses 3V3, not 5V0. Getting that wrong will probably damage your Pi.
by davidcoton
Wed Jun 13, 2018 7:08 pm
Forum: Beginners
Topic: X11VNC install error
Replies: 2
Views: 67

Re: X11VNC install error

Hello, I have a clean install on PI 3+ I am trying to install x11vnc and get this: pi@raspberrypi:~ $ sudo apt-get clean pi@raspberrypi:~ $ sudo apt-get install x11vnc Reading package lists... Done Building dependency tree Reading state information... Done The following extra packages will be insta...
by davidcoton
Tue Jun 12, 2018 3:48 pm
Forum: General discussion
Topic: Relay Module KY-019 5V
Replies: 86
Views: 4855

Re: Relay Module KY-019 5V

I now understand that I don't need to use a wire as thick as possible, because if only a few mA of 220VAC leakage current passing through my body, the earth leakage detector in my home will notice it and activate the mains circuit breaker, and save my life. And what happens if someone takes you pro...
by davidcoton
Mon Jun 11, 2018 9:36 pm
Forum: General discussion
Topic: Changing static IP
Replies: 7
Views: 187

Re: Changing static IP

jadro wrote:
Mon Jun 11, 2018 9:28 pm
I use fixed ip because of having mqtt connections from clients to raspberry pi mqtt and http servers
Fair enough, but fix them by IP reservation on the router. All the benefits of fixed addresses with none of the portability problems.
by davidcoton
Mon Jun 11, 2018 9:22 pm
Forum: Beginners
Topic: Can't connect to Pi via SSH
Replies: 4
Views: 140

Re: Can't connect to Pi via SSH

mt stringer wrote:
Mon Jun 11, 2018 2:43 am
Thanks. And pack a lunch. :-(
You don't need lunch. Program your Pi to order pizza when it connects.... :lol:
by davidcoton
Mon Jun 11, 2018 9:19 pm
Forum: General discussion
Topic: Suggesstions For An Innovative Science Project
Replies: 16
Views: 439

Re: Suggesstions For An Innovative Science Project

If anyone here had an innovative, world changing idea that could be developed in two weeks, wouldn't we develop it ourselves? Pehaps you could compile a database of problems looking for solutions, that could possibly be solved with a Pi? Then publish it on the WWW for future students to grab a probl...
by davidcoton
Mon Jun 11, 2018 9:05 pm
Forum: General discussion
Topic: Changing static IP
Replies: 7
Views: 187

Re: Changing static IP

I do have port forward but some internet providers have range of known ips from 192.168.5.1 to 192.168.5.999 or 192.168.8.1 to 192.168.8.999 i think it is predifined in config of router. Jadro 999 is not valid. Each part of the address is an 8 bit unsigned number, so the decimal top limit is 255. T...
by davidcoton
Mon Jun 11, 2018 8:55 pm
Forum: General discussion
Topic: How do I edit my post?
Replies: 13
Views: 374

Re: How do I edit my post?

Well, it could be that a quite recent (in relative terms) BBS overhaul has changed this edit blocking behavior, that would explain it. I don't think either the new software or the reorganisiation has changed the edit behaviour. AFAICT the behaviour was and is as hippy described (and demonstrated). ...
by davidcoton
Mon Jun 11, 2018 8:47 pm
Forum: General discussion
Topic: What wires are required for plugging in the Raspberry Pi?
Replies: 4
Views: 341

Re: What wires are required for plugging in the Raspberry Pi?

The red PoWeR LED should be continuously lit. If it flashes a pattern, this usually indicates an out-of-date os that must be updated/upgraded before it will work on a Pi3B+ If it flashes off at random, that indicates an inadequate supply. The recommended supply for a Pi3B+ is 5V1 2A5. You cannot nor...
by davidcoton
Sun Jun 10, 2018 10:05 pm
Forum: Troubleshooting
Topic: Router Reset, Pi gone?
Replies: 5
Views: 202

Re: Router Reset, Pi gone?

If you can reserve the address (part of the pool) for the Pi's MAC address on the router, you shouldn't need to set a fixed IP address on the Pi -- the router will always assign the reserved IP address to the Pi. This is a better solution anyway, since it means you can connect your Pi to other netwo...
by davidcoton
Thu Jun 07, 2018 3:53 pm
Forum: Beginners
Topic: RPi Zero Custom Power Circuit
Replies: 4
Views: 160

Re: RPi Zero Custom Power Circuit

The only way I see it guys, is it to short the 3.3V output rails from the Pi and from my PSU. Through a capacitor-inductor-capacitor filter calculated with cutoff frequency of 100KHz or so. The problem with that is in this case the output of the lower potential DC-DC converter will be feed with cur...
by davidcoton
Tue Jun 05, 2018 10:32 pm
Forum: Off topic discussion
Topic: What If I Told You... You could have a bad to the box Matrix Pi
Replies: 59
Views: 2810

Re: What If I Told You... You could have a bad to the box Matrix Pi

MaxTheSpy wrote:
Tue Jun 05, 2018 10:14 pm
Imperf3kt wrote:
Tue Jun 05, 2018 10:07 pm
The only thing rotating here is my head, this discussion has strayed so far from the title its not even clear how we got here.
Stick around and Ill show you just how far this rabbit hole goes.
It's not a rabbit hole, it's a freak wormhole in the fabric of the space-time continuum.
by davidcoton
Tue Jun 05, 2018 10:27 pm
Forum: Troubleshooting
Topic: I Seem to fail to create a SD Backup or Restore
Replies: 5
Views: 129

Re: I Seem to fail to create a SD Backup or Restore

BBCHansPi wrote:
Tue Jun 05, 2018 8:07 pm
Hi all, i have a problem in trying to make a backup image from a pi 3b with a windowz laptop.
Are you sure the laptop card reader is SDHC complatible? Many built-in ones are not. Try a plug-in USB SDCard reader with SDHC compatibility.
by davidcoton
Tue Jun 05, 2018 8:20 pm
Forum: Off topic discussion
Topic: What If I Told You... You could have a bad to the box Matrix Pi
Replies: 59
Views: 2810

Re: What If I Told You... You could have a bad to the box Matrix Pi

Give that rod and mass system a spin What is involved in that? No less or more than applying a force, thus accelerating the mass into a rotational path. Resolve the applied force and you will end up with the centripetal component. Think about the planet and satellite model and it becomes even more ...

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