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by TimG
Mon Sep 16, 2019 11:58 pm
Forum: Troubleshooting
Topic: sshfs causes pcmanfm to go berserk
Replies: 0
Views: 40

sshfs causes pcmanfm to go berserk

It seems that any failed sshfs connection, with a mount-point inside the user's home directory, will cause pcmanfm to go berserk and load the CPU 100% Steps to reproduce with latest Raspbian/Debian Buster: After logging-in to the gui, run sudo apt-get update sudo apt-get install sshfs mkdir ~/tmp ss...
by TimG
Thu Aug 29, 2019 6:41 pm
Forum: General discussion
Topic: raspberrypi-ui-mods
Replies: 3
Views: 289

Re: raspberrypi-ui-mods

Ah-ha! Yes. In /var/log/lightdm/x-0.log Fatal server error: (EE) no screens found(EE) Adding hdmi_force_hotplug=1 to /boot/config.txt seems to have solved the problem. The Pi4 is running headless, and will be accessed via VNC. I don't remember that being needed on a Pi3+ with Stretch. I assume it's ...
by TimG
Thu Aug 29, 2019 6:09 pm
Forum: General discussion
Topic: raspberrypi-ui-mods
Replies: 3
Views: 289

raspberrypi-ui-mods

It used to be possible to add the desktop environment to raspbian-lite by installing a single package (and all its dependencies): apt-get install raspberrypi-ui-mods This does not seem to be working on a Pi4 with 2019-07-10-raspbian-buster-lite.img. After running raspi-config and choosing "B4 Deskto...
by TimG
Wed Aug 07, 2019 4:49 pm
Forum: General discussion
Topic: Why moving to 64bit?
Replies: 259
Views: 18290

Re: Why moving to 64bit?

piglet wrote:
Wed Aug 07, 2019 11:56 am
jamesh wrote:
Tue Aug 06, 2019 2:44 pm
although we are learning by osmosis.
*cough* diffusion is the closer analogy, unless you've a semi-permeable membrane in the office for the information to pass through *cough*
The skull is semi-permeable to information. At least, some are.
by TimG
Mon Jul 08, 2019 11:22 pm
Forum: General discussion
Topic: Power Supply for multiple RAPI4B+
Replies: 7
Views: 561

Re: Power Supply for multiple RAPI4B+

The official RPi power supply is actually hard to beat on price and reliability. There are industrial power supplies which would be more compact, but good ones aren't cheap -- especially once you factor in cabling, connectors, and a ventilated case. Cheaper power supplies are the cause of endless di...
by TimG
Tue Jul 02, 2019 6:33 am
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 861
Views: 88923

Re: Raspberry Pi 4 Thread - general discussion

Just a guess, but it looks to me like the extra componentry there is related to the USB hub. On closer examination it looks like the power circuitry is for the VIA chip and SOC. I guess the main power chip does not generate all the necessary voltage levels. That still leaves the two 8-pin chips nea...
by TimG
Mon Jul 01, 2019 11:45 pm
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 861
Views: 88923

Re: Raspberry Pi 4 Thread - general discussion

Purely out of curiosity, what are the Pi4's extra components around the audio jack? PWM drivers and a stabilised power supply? How is the Pi4's audio quality compared to previous models?

LHS: Pi3B+
RHS: Pi4
pijacksmall.jpg
pijacksmall.jpg (155.48 KiB) Viewed 1184 times
by TimG
Sun Jun 30, 2019 4:58 pm
Forum: General discussion
Topic: Bluetooth audio glitches (with Pi-3 only)
Replies: 1
Views: 349

Re: Bluetooth audio glitches (with Pi-3 only)

I noticed (systemctl status hciuart) that the bluetooth communication is 3Mbps (with flow-control) on the 3B+, but only 0.92Mbps (without flow-control) on the 3B. Both should be sufficient for an A2DP audio stream, but it's the only difference I could spot. Anyway, now that Buster is out (*before* D...
by TimG
Mon Jun 24, 2019 4:42 pm
Forum: General discussion
Topic: Raspberry Pi 4 Thread - general discussion
Replies: 861
Views: 88923

Re: Raspberry Pi 4 Thread - general discussion

As the WiFi is just a module, I assume it is still fine for RS/Farnell to have orders for customised Pi4 without the WiFi/BT module there. Cutting the antenna trace would be sufficient, shirley? And/or a solder blob shorting it to ground. No, I'm not going to try it on my soon-to-arrive Pi4. Bravo ...
by TimG
Mon Jun 24, 2019 4:20 pm
Forum: General discussion
Topic: Simple circuit to step down 120VAC
Replies: 3
Views: 180

Re: Simple circuit to step down 120VAC

Here's a couple of useful links: https://designercircuits.com/DesignNote1c.pdf https://hackaday.com/2017/04/04/the-shocking-truth-about-transformerless-power-supplies/ Even though you need very little power, you do need mains-rated fail-safe components. It's usually cheaper and easier to find a disu...
by TimG
Sat Jun 22, 2019 12:52 am
Forum: General discussion
Topic: Bluetooth audio glitches (with Pi-3 only)
Replies: 1
Views: 349

Bluetooth audio glitches (with Pi-3 only)

Hi Everybody, I have set up a Pi as a bluetooth speaker, and I'm getting prominent audio glitches every few seconds. The odd thing is it *only* happens with a Pi-3B using the built-in bluetooth. Other Pi models are not affected. Does anybody know if this can be cured? A Pi-3B+ and the *same* uSD car...
by TimG
Wed Jun 12, 2019 10:59 am
Forum: General discussion
Topic: Running an RPI outside?
Replies: 12
Views: 557

Re: Running an RPI outside?

Re. power: To avoid putting mains power in a box exposed to the weather, I've used an old 18V laptop power supply in combination with a small regulator like these: https://www.tracopower.com/products/browse-by-category/detail/dc-dc-converters/non-isolated-step-down-regulators/ The 18V supply (the ex...
by TimG
Tue Jun 04, 2019 11:39 am
Forum: Camera board
Topic: Soldering camera cable
Replies: 1
Views: 187

Soldering camera cable

Does anybody know if the camera ribbon cable can withstand soldering? I'd like to join a PiZero-to-camera adapter cable to a normal cable without using extra intermediate connectors. https://cdn.shopify.com/s/files/1/0174/1800/products/Camera_cable_1_of_3_19028afc-2f5f-40ba-863d-293ee88ef649_256x256...
by TimG
Tue Jun 04, 2019 11:16 am
Forum: General discussion
Topic: light detector with photo transistor
Replies: 34
Views: 1667

Re: light detector with photo transistor

A digital light detector would save you a lot of work. For example, https://www.adafruit.com/product/4162 https://cdn-learn.adafruit.com/assets/assets/000/073/757/small240/adafruit_products_VEML7700TopHeader.jpg On the other hand if you want to learn about phototransistors, here are a couple of usef...
by TimG
Thu May 23, 2019 3:29 am
Forum: Advanced users
Topic: Fast boot on Pi-Zero with C library and GPIO access
Replies: 2
Views: 277

Re: Fast boot on Pi-Zero with C library and GPIO access

It's been a while since I worked on fast-booting, but on a Pi Zero it's possible to start running code within 2 - 2.5 seconds. I used a systemd service file to launch my script as early as possible, like this: # example.service # run as early as possible [Unit] Description=Example Service DefaultDep...
by TimG
Sat Apr 27, 2019 12:55 pm
Forum: Advanced users
Topic: LM386 Audio Amp Module Producing buzzing/cracking noise
Replies: 6
Views: 601

Re: LM386 Audio Amp Module Producing buzzing/cracking noise

- The LM386 has two audio inputs: inverting and non-inverting. Are they both connected to something? - The speaker output needs a DC-blocking capacitor. - Likely the USB headphone output needs a load. Connect a set of headphones in parallel. If you still get distortion, you may need DC-blocking capa...
by TimG
Thu Apr 11, 2019 5:58 pm
Forum: General discussion
Topic: raspistill crashes every 35 minutes
Replies: 4
Views: 288

Re: raspistill crashes every 35 minutes

Wow, thanks for the fix, and the build instructions. The updated binary has been running for an hour now with no glitches. Not having to monitor raspistill is going to simplify my code a lot.
by TimG
Thu Apr 11, 2019 4:01 pm
Forum: General discussion
Topic: raspistill crashes every 35 minutes
Replies: 4
Views: 288

Re: raspistill crashes every 35 minutes

Ah-ha. Yes, I just realised that my crashes are happening every 2^31 us.

$ raspistill -v
"raspistill" Camera App (commit 7cbfbd38d982 Tainted)
by TimG
Thu Apr 11, 2019 3:07 pm
Forum: General discussion
Topic: raspistill crashes every 35 minutes
Replies: 4
Views: 288

raspistill crashes every 35 minutes

Hi everybody, Running raspistill in timelapse mode I'm encountering freezes and unexpected exits. These happen very regularly, and one of the following always seem to happen (in fact they alternate): - The raspistill process freezes and has to be killed. - The raspistill process gives an error like ...
by TimG
Thu Jan 31, 2019 5:33 pm
Forum: General discussion
Topic: How to prevent monitor sleep, on Raspbian Stretch Lite?
Replies: 4
Views: 746

Re: How to prevent monitor sleep, on Raspbian Stretch Lite?

Hi andreioniga, Here's the recipe I use with a similar setup (qiv running under X and Raspbian-lite). At least with my monitor, "BlankTime" seems to be the only parameter which really does anything. mkdir /etc/X11/xorg.conf.d # disable X blanking chmod a+rx /etc/X11/xorg.conf.d echo >/etc/X11/xorg.c...
by TimG
Wed Jan 23, 2019 12:24 pm
Forum: General discussion
Topic: Raspbian with Read-only Root
Replies: 191
Views: 86163

Re: Raspbian with Read-only Root

Hi bouwew, I think the " /boot/initrd.img-4.14.79-v7+ does not exist. Cannot update. " message is a hang-over from Debian which expects a different kernel file naming scheme. Use it as a reminder that initrd.img needs to be updated by hand. Probably if you had a copy of initrd.img named with the app...
by TimG
Sun Jan 20, 2019 12:43 pm
Forum: General discussion
Topic: How to turn on relay one time in every hour
Replies: 41
Views: 1979

Re: How to turn on relay one time in every hour

In addition to Gordon77's comment, the read-back to GPIO12 mustn't be more than 3.3V.
by TimG
Fri Jan 18, 2019 6:21 pm
Forum: General discussion
Topic: new to soldering - safety questions, etc.
Replies: 46
Views: 3031

Re: new to soldering - safety questions, etc.

The essential soldering accessory is a brass-wool tip cleaner. Forget sponges and that weird gunge that comes in a little tin.
https://shop.pimoroni.com/products/sold ... ip-cleaner
by TimG
Tue Jan 15, 2019 1:37 am
Forum: Advanced users
Topic: Raspberry PI cold boot attack protected / Zero out RAM after boot?
Replies: 71
Views: 4975

Re: Raspberry PI cold boot attack protected / Zero out RAM after boot?

RDPUser wrote:
Mon Jan 14, 2019 8:27 pm
So to secure against this "cold boot SD-Card swap attack" a few lines of code are sufficient.
It sounds like a generous layer of epoxy would be just as effective.
Forcing the agents of the deep-state to resort to alternative decryption techniques: https://www.xkcd.com/538/
by TimG
Tue Jan 08, 2019 11:10 pm
Forum: General discussion
Topic: Raspberry Pi Zero W not working well with power supply
Replies: 7
Views: 688

Re: Raspberry Pi Zero W not working well with power supply

I think it's likely your Pi is fine, and your problems are caused by bad cables. But without a multimeter it's difficult to make any suggestion.

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