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by Aydan
Thu Jun 04, 2020 6:12 am
Forum: Advanced users
Topic: Off grid file transfer
Replies: 7
Views: 199

Re: Off grid file transfer

I didn't read the OP's post as the USB storage being set in stone, just as being one way to transfer the data. So to recap: If a zero is used and USB storage is used, USB OTG is out since the zero has only one USB controller which can either be host, for USB storage, or OTG Device for e.g. ethernet ...
by Aydan
Wed Jun 03, 2020 3:25 pm
Forum: Advanced users
Topic: Off grid file transfer
Replies: 7
Views: 199

Re: Off grid file transfer

thagrol wrote:
Wed Jun 03, 2020 12:35 pm
Aydan wrote:
Wed Jun 03, 2020 9:37 am
Or you could use USB OTG ethernet gadget to access the Raspberry via USB Networking.
Only on a 4B and only via the USB C port which means you need to find another way to provide power.
The zero, 1A, 3A and so on as well, and the OP did mention using a zero.

Regards
Aydan
by Aydan
Wed Jun 03, 2020 10:12 am
Forum: Advanced users
Topic: What is the most reliable way (circa mid 2020) to run a firstboot script on Raspberry OS or Ubuntu?
Replies: 3
Views: 200

Re: What is the most reliable way (circa mid 2020) to run a firstboot script on Raspberry OS or Ubuntu?

With systemd you can create a simple oneshot service which runs a shell script. In this shell script you can then check for the existence of e.g. a file in Boot, perform your actions and remove the file in boot. Have a look at this: https://github.com/RPi-Distro/raspberrypi-sys-mods/blob/master/debi...
by Aydan
Wed Jun 03, 2020 9:37 am
Forum: Advanced users
Topic: Off grid file transfer
Replies: 7
Views: 199

Re: Off grid file transfer

What you could do is add a Button/Switch to the Raspberry that allows you to Enable/DIsable the Wifi AP on demand.
Or you could use USB OTG ethernet gadget to access the Raspberry via USB Networking.

Regards
Aydan
by Aydan
Fri May 15, 2020 11:29 am
Forum: General discussion
Topic: USB Connection without a PC....
Replies: 19
Views: 745

Re: USB Connection without a PC....

I apologize for the delay in my getting back to this thread, I was away but I'm back now. The equipment is an ICOM 7300 radio. When I plug it directly into a PC it shows two USB ports over one "Type B" USB connection. I.E. the PC "sees" two COM ports. Each port has different functions although I on...
by Aydan
Wed May 13, 2020 5:12 pm
Forum: Camera board
Topic: Raspberry Pi High Quality Camera
Replies: 150
Views: 9458

Re: Raspberry Pi High Quality Camera

Of course. It's a new MMAL flag that is passed to the camera control port. Check out the pull request to see what changed. But this will only activate the overlay for the preview window, this will not deliver the numbers drawn on it back to raspisitll/vid. Or did I got this wrong? Correct, the numb...
by Aydan
Wed May 13, 2020 2:03 pm
Forum: Camera board
Topic: Raspberry Pi High Quality Camera
Replies: 150
Views: 9458

Re: Raspberry Pi High Quality Camera

I've just merged a commit in our userland repo for a new option in the raspi apps to help with focusing. Superimposes a FoM window on the display. https://github.com/raspberrypi/userland/pull/621 So you will need to checkout userland and rebuild to get a new version of raspistill etc. Will be a whi...
by Aydan
Thu Feb 27, 2020 4:23 pm
Forum: Troubleshooting
Topic: Error: when_changed() takes exactly 1 argument (3 given)
Replies: 43
Views: 1381

Re: Error: when_changed() takes exactly 1 argument (3 given)

If you only have one signal of an encoder connected, your counts will definitely be wrong, because you cannot distinguish direction. Even if the motor only runs in one direction, the signal can "flicker" on the edge and you will always increment the count, although it would actually toggle between i...
by Aydan
Fri Feb 14, 2020 8:00 am
Forum: Troubleshooting
Topic: Rpi 4 after most recent update: wifi broken -> wpasupplicant configuration spoiled
Replies: 11
Views: 654

Re: Rpi 4 after most recent update: wifi broken -> wpasupplicant configuration spoiled

On buster/stretch/jessie, do not use /etc/network/interfaces.
For servers I disable NetworkManager and use systemd-networkd and configure the interfaces in /etc/systemd/network with appropriate *.netdev and *.network files.

Regards
Aydan
by Aydan
Fri Feb 14, 2020 6:50 am
Forum: Python
Topic: GPIO and subprocess module Python3
Replies: 7
Views: 638

Re: GPIO and subprocess module Python3

b'' just means it's a bytes object, not a string. Bytes-Object means raw byte data, instead of character representation like in a string. Think of e.g. greek characters. bytes will show the raw codes (e.g. UTF-8) while string will show the actual characters when you 'print' them. you can convert on...
by Aydan
Tue Feb 11, 2020 9:34 pm
Forum: Python
Topic: GPIO and subprocess module Python3
Replies: 7
Views: 638

Re: GPIO and subprocess module Python3

>>> s=subprocess.Popen('/usr/bin/top',stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.STDOUT) >>> s.stdout.read() b'top: failed tty get\n' 'top' needs a tty, not a pipe, I'd use python3-psutil instead. Rearding reading from the pipe, the pipe has a buffer. Once the buffer is full, ...
by Aydan
Thu Jan 30, 2020 1:40 pm
Forum: Python
Topic: GPIO and subprocess module Python3
Replies: 7
Views: 638

Re: GPIO and subprocess module Python3

Check_output will only return after the command has finished. For interactive processes and/or processes that have a lot of output use subprocess.Popen with stdin, stderr and stdout set to PIPE. Then you can use the pipes to communicate with the process. ATTENTION: the process will block when the ST...
by Aydan
Wed Dec 18, 2019 4:18 pm
Forum: Advanced users
Topic: Disable 10ms interrupt on core 2&3
Replies: 3
Views: 959

Re: Disable 10ms interrupt on core 2&3

@weishisky
what you try to do is a device driver, so implement it as a device driver in the kernel (as a kernel module), not in userspace.
For reference look at the onewire gpio driver for the raspi.

Regards
Aydan
by Aydan
Thu Dec 12, 2019 1:58 pm
Forum: HATs and other add-ons
Topic: PoE HAT for RPi Zero
Replies: 0
Views: 242

PoE HAT for RPi Zero

I'm thinking about making a PoE HAT for the RPi Zero, to make PoE IP cameras. If I use the LAN9512 Ethernet/USB Controller and have a µSD with bootcode.bin in the RPi0, would that be enough to allow network booting like on the RPi3? Is any special pinstrap configuration needed for the LAN9512? I hav...
by Aydan
Thu Dec 12, 2019 1:17 pm
Forum: General discussion
Topic: [Solved] Annoying feature of 'apt-get uprgade'
Replies: 42
Views: 2496

Re: Annoying feature of 'apt-get uprgade'

But if 'apt' simply overwrites user modified configuration files, or if it doesn't, doesn't offer a choice, that's potentially more problematic than the issue with 'apt-get', arguably even less fit for purpose. I think apt overwrites config files only when they have not been changed by the user. Ot...
by Aydan
Tue Dec 10, 2019 10:55 am
Forum: Troubleshooting
Topic: analog Sound Raspberry PI 4 is mono, not stereo
Replies: 52
Views: 4178

Re: analog Sound Raspberry PI 4 is mono, not stereo

@RossDv8: Are you sure you don't have a broken audio cable?

Your description of sometimes it works, sometime it doesn't, sounds to me like an intermittent connection of the right channel.

Regards
Aydan
by Aydan
Wed Dec 04, 2019 11:19 am
Forum: Troubleshooting
Topic: mmcblk0 unnaccessable
Replies: 10
Views: 579

Re: mmcblk0 unnaccessable

So I went and did the code using sda: sudo xzcat genpi64.img.xz > /dev/sda && sync and got this result: bash: /dev/sda: Permission denied What happened?? There's two things why it doesn't work: #1 is sda1 is mounted, as RonR has said. #2 is that the output redirection (">") to /dev/sda does not run...
by Aydan
Wed Nov 20, 2019 1:07 pm
Forum: Advanced users
Topic: Can I pass Data through a Relay.
Replies: 2
Views: 309

Re: Can I pass Data through a Relay.

I want to connect two Pi's to the same SD card and use a relay to signal when one Pi will write an image to the SD card and then signal when the other Pi will boot using the written image. My question here is: "what do you want to achieve with this?" It is technicaly possible to switch the SD card ...
by Aydan
Wed Nov 13, 2019 12:28 pm
Forum: Troubleshooting
Topic: rPi Zero W HDMI cuts in and out before dying
Replies: 1
Views: 119

Re: rPi Zero W HDMI cuts in and out before dying

This looks like a thermal problem. When it heats up, the problem intensifies. If you haven't done so already, enable ssh and a wlan connection to check if the Pi is still accessible over ssh when the display cuts out. If it is, then increase the hdmi_drive in config.txt. This may fix the problem. Re...
by Aydan
Wed Nov 13, 2019 12:22 pm
Forum: Troubleshooting
Topic: Upgrade to buster partial failure (i think)
Replies: 6
Views: 662

Re: Upgrade to buster partial failure (i think)

If you rebooted after the update, and the OS is more or less up and running, the first thing to try would be to run "apt install --fix-broken". There may be a message to run "dpkg-reconfigure --all". If that is tha case, run the command. If that fails, check the journal what exactly failed. Regards ...
by Aydan
Mon Nov 04, 2019 6:08 pm
Forum: General discussion
Topic: Nightly email hints at trouble to come...
Replies: 5
Views: 874

Re: Nightly email hints at trouble to come...

The installed packages are likely to be fine, as once written, they remain untouched. Your collected data is going to be at risk here, and I'd check the integrity of that ASAP, then back it all up somewhere safe. That assumption is fundamentally wrong for flash storage due to the size of erase bloc...
by Aydan
Mon Nov 04, 2019 1:36 pm
Forum: General discussion
Topic: Nightly email hints at trouble to come...
Replies: 5
Views: 874

Re: Nightly email hints at trouble to come...

You can check the intergrity of files installed by packages using "debsums". Checking files which are not part of a deb-package will be harder. You could save the checksum for each file in an xattr of said file, and have a script run over all files periodically comparing the saved checksum against t...
by Aydan
Thu Oct 24, 2019 1:06 pm
Forum: Troubleshooting
Topic: Eth1 management access problem
Replies: 5
Views: 274

Re: Eth1 management access problem

@labnario:
please check dmesg for undervoltage warnings and USB disconnects.

The problem could be undervoltage on the USB Ethernet adapter, or the adapter has a thermal problem and malfunctions after warming up.

Regards
Aydan
by Aydan
Wed Oct 23, 2019 9:54 am
Forum: Advanced users
Topic: RP4 Cluster Hardware?
Replies: 16
Views: 1586

Re: RP4 Cluster Hardware?

Ya the network boot is quite intriguing and I would have to assess how to net boot for more than 255 items (subnet). You can have a subnet larger than class c (mask 255.255.255.0) a subnet with mask 255.255.248.0 will allow 1022 nodes and so on. You can basically have subnets up to class A if you w...
by Aydan
Fri Oct 18, 2019 2:44 pm
Forum: Advanced users
Topic: New RT (Real Time) kernel branch
Replies: 65
Views: 23105

Re: New RT (Real Time) kernel branch

#1 you can get a root shell with "sudo -i", no need for a root pw.
#2 you can prevent package updates by "holding" a package via "apt-mark hold <package-name>"
the package in this case is "raspberrypi-kernel"

Regards
Aydan

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