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by jbudd
Sun Feb 16, 2020 4:51 pm
Forum: General discussion
Topic: Remote power button or reset button?
Replies: 9
Views: 293

Re: Remote power button or reset button?

Connect by ssh, sudo reboot?

I have a Pi running Node-Red which accepts an MQTT message pi/reboot and executes sudo reboot to do a clean shutdown and reboot.
Could do the same thing with a Python script to subscribe to MQTT and reboot too.
by jbudd
Thu Feb 13, 2020 10:05 pm
Forum: Troubleshooting
Topic: Rpi 4 after most recent update: wifi broken -> wpasupplicant configuration spoiled
Replies: 11
Views: 381

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

Or you could skip modifying the OS altogether and reserve the IP in your router's DHCP settings. Much easier, and less problematic than mucking about with system files (and it only needs to be done once, after which the same Pi will always boot to the same IP, even with a new card or OS). Except wh...
by jbudd
Mon Feb 10, 2020 11:32 am
Forum: General discussion
Topic: Raspbian buster
Replies: 16
Views: 568

Re: Raspbian buster

On both laptops I have access to (Windows 10, Toshibas) the SD card reader sometimes stops working after the laptop goes to sleep. Disabling and reenabling the card reader in Device Manager / "Memory technology devices" kicks it back to life.
by jbudd
Mon Feb 10, 2020 12:09 am
Forum: Beginners
Topic: case - fan compatibility
Replies: 14
Views: 350

Re: case - fan compatibility

In my opinion the "overheating" issue has been resolved by changes in the firmware (or something). My Pi 4 no longer gets hot enough to throttle the CPU regardless of load. Hot enough to cause discomfort to little fingers in direct contact with the chip though. Mind you, it's in a PiBow case. Possib...
by jbudd
Sun Feb 09, 2020 11:48 pm
Forum: General discussion
Topic: Buying more than one Pi zero?
Replies: 25
Views: 799

Re: Buying more than one Pi zero?

I can search for things I know exist, and never find them while I am searching. Then a week later, 10 pages into a different search result, there it is!
That wouldn't happen if Google wasn't keeping it's beady eye on you! ;)
by jbudd
Sun Feb 09, 2020 2:24 pm
Forum: General discussion
Topic: Buying more than one Pi zero?
Replies: 25
Views: 799

Re: Buying more than one Pi zero?

To clarify, that was Zero WH
by jbudd
Sun Feb 09, 2020 2:08 pm
Forum: General discussion
Topic: No /tmp filesystem
Replies: 7
Views: 250

Re: No /tmp filesystem

Well I wasn't "planning" on storing anything there! The Pi with 100% full root fs has PiVPN installed on it, using wireshark. Currently wireshark is dumping a 40 - 50 MB file into /tmp every 20 minutes and the VPN isn't even in use. Obviously that's not a problem to discuss here. Edit - I have had /...
by jbudd
Sun Feb 09, 2020 1:55 pm
Forum: General discussion
Topic: Buying more than one Pi zero?
Replies: 25
Views: 799

Re: Buying more than one Pi zero?

At The Pi Hut, where Pi Zero W's are currently in stock at £13, you can buy 5 for £65 and the total shipping charge is £2.99. (UK, Royal Mail 1st class)

I did look at another authorised retailer but they were out of stock.
by jbudd
Sun Feb 09, 2020 1:43 pm
Forum: General discussion
Topic: No /tmp filesystem
Replies: 7
Views: 250

Re: No /tmp filesystem

Thanks jahboater.

A Pi is constrained by a) potentially only 256MB memory and b) limited writes before the SD card dies
I guess a) is why /tmp isn't a tmpfs filesystem?

What happens if a /tmp filesystem uses up the allocated memory - the Pi grinds to a halt, or frantic swapping?
by jbudd
Sun Feb 09, 2020 1:27 pm
Forum: General discussion
Topic: Shell script in init.d
Replies: 9
Views: 322

Re: Shell script in init.d

Yes, your code worked. Well mostly. The define statement and the file handling did not I'm not sure what you mean by the define statement: sunrise="${myarray[0]}" ? or ARG="-ISO 100 -drc med -co 10 -n -w 1024 -h 768 -ss 450 -tl 30000 -t 2147483647 -o /run/shm/$SCR.jpg" ? If it's the former, make su...
by jbudd
Sun Feb 09, 2020 12:22 am
Forum: Troubleshooting
Topic: Pi Zero W appears to be dead after electrical short
Replies: 4
Views: 174

Re: Pi Zero W appears to be dead after electrical short

I'm afraid your Pi is dead.

Either there was a voltage spike on one of the cables plugged in to it or maybe you fried it with static electricity.

You really should turn the power off before plugging / unplugging anything.
by jbudd
Sat Feb 08, 2020 3:39 pm
Forum: General discussion
Topic: No /tmp filesystem
Replies: 7
Views: 250

No /tmp filesystem

I only just noticed this when trying to upgrade one of my Pies (8GB SD, Raspbian Buster Lite, Sept 2019) /tmp is just a directory not a filesystem and accumulated junk there caused the root filesystem to fill up. pi@APi:/ $ df -k Filesystem 1K-blocks Used Available Use% Mounted on /dev/root 7312912 ...
by jbudd
Sat Feb 08, 2020 2:45 pm
Forum: General discussion
Topic: Shell script in init.d
Replies: 9
Views: 322

Re: Shell script in init.d

I don't understand your Excel code but I think it's probably exactly what the shell script I offered above is trying to do.
Did you try it, were there problems?
by jbudd
Thu Feb 06, 2020 7:14 pm
Forum: Troubleshooting
Topic: MQTT - Cloudmqtt (Working) Mosquitto (not) Same script
Replies: 7
Views: 220

Re: MQTT - Cloudmqtt (Working) Mosquitto (not) Same script

Is it possible that the message topic or contents are not actually identical when sent via the two brokers? Perhaps you have a trailing null \0 or carriage return \r character? I would test this by having the script print topic_sub, msg.topic and msg.payload, then exit. And pipe it's output through ...
by jbudd
Wed Feb 05, 2020 1:33 am
Forum: General discussion
Topic: Shell script in init.d
Replies: 9
Views: 322

Re: Shell script in init.d

How do you obtain sunrise and sunset times and in what format? One possible solution is to save them in a file, expressed as the number of seconds since the Unix epoch, first line sunrise time, second line sunset time. (Obviously you would have to populate this file at startup and again at midnight)...
by jbudd
Wed Feb 05, 2020 12:11 am
Forum: General discussion
Topic: Firefox ESR onRaspberry Pi B+
Replies: 9
Views: 387

Re: Firefox ESR onRaspberry Pi B+

... Chromium which synchronizes the web browser with Google ... I thought that the chromium browser is supposed to be "degooglised"? I prefer to share as little as possible of my life with organisations that consider me their property to sell. A good reason to struggle with Firefox ESR. And on the ...
by jbudd
Sun Feb 02, 2020 3:10 am
Forum: Beginners
Topic: Neccessity of iptables/fail2ban
Replies: 2
Views: 350

Re: Neccessity of iptables/fail2ban

If you open port 22 to the internet, you very quickly get attempts to login to your Pi using lists of login ids and passwords. Install fail2ban and you can see them logged in /var/log/fail2ban.log I think that the computers trawling the internet for vulnerable devices tend to be programmed to evade ...
by jbudd
Sun Feb 02, 2020 2:34 am
Forum: General discussion
Topic: Data Usage and Production
Replies: 11
Views: 852

Re: Data Usage and Production

"What data does the Raspberry Pi use and how does it produce new data?" sounds like a dumb question. But perhaps not... A lot of computer systems are "black boxes" for example the engine management system for a car - you can't see what goes on inside them but you know what data they accept and what ...
by jbudd
Tue Jan 28, 2020 11:41 am
Forum: General discussion
Topic: Embedded SO for Raspberry pi 2
Replies: 3
Views: 201

Re: Embedded SO for Raspberry pi 2

The .img file is a single file containing all the contents of the disk/sd card it was created from, including the file systems eg /boot and their contents eg /boot/bootcode.bin. I have no idea what SO, RTEMS or BSP mean so I can't really comment about renaming .exe files as .img beyond it sounds a b...
by jbudd
Tue Jan 28, 2020 10:11 am
Forum: Beginners
Topic: Case FAN : should it suck, or should it blow ?
Replies: 8
Views: 315

Re: Case FAN : should it suck, or should it blow ?

Current models of Pi are designed to distribute heat over the whole board, though obviously the CPU and other chips are hottest. For most efficient cooling the air should flow over the Pi from the least warm to the hottest bits which sugests sucking it in at the edges and out over the CPU. I tried m...
by jbudd
Sat Jan 25, 2020 1:01 am
Forum: Beginners
Topic: Setting up a pi with a chromebook
Replies: 3
Views: 136

Re: Setting up a pi with a chromebook

I have never tried it since I don't have a chromebook. However: https://willhaley.com/blog/setup-raspbe ... hromebook/
by jbudd
Thu Jan 23, 2020 5:49 pm
Forum: Troubleshooting
Topic: Rpi can't connect to internet using eth0
Replies: 2
Views: 73

Re: Rpi can't connect to internet using eth0

Tried giving pi a static op adress editing /etc/dhcp.conf.
Still the pi gets a wrong ip.
You shouldn't have to give the Pi a static IP, but if you must do, the file is /etc/dhcpcd.conf not /etc/dhcp.conf
by jbudd
Wed Jan 22, 2020 4:09 pm
Forum: General discussion
Topic: Future of raspberry pi - software related
Replies: 382
Views: 21477

Re: Future of raspberry pi - software related

This appears to be a commercial installation type of use case. No, it is not: In my case, I am retired and am working benevolently for an association promoting environmental measurement stations. The stations are deployed at homes of people, who are willing to provide a station on their own expense...
by jbudd
Wed Jan 15, 2020 5:54 pm
Forum: Troubleshooting
Topic: Can't connect to RPi4
Replies: 17
Views: 351

Re: Can't connect to RPi4

Windows offering to format the card is not an issue. Just say No. A Raspbian SD card has an ext4 partition which Windows cannot understand so it offers to format.

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