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by plugwash
Tue Jan 28, 2020 6:04 pm
Forum: Python
Topic: Type object ‘datetime.datetime’ has no attribute ‘datetime’
Replies: 1
Views: 57

Re: Type object ‘datetime.datetime’ has no attribute ‘datetime’

Short answer: remove the "from datetime import datetime" Long answer: First off in python, pretty much everything is an object. Variables are names in a namespace that refer to those objects. This is often glossed over in tutorials, but it's pretty important to understanding some of these edge cases...
by plugwash
Tue Jan 28, 2020 4:40 pm
Forum: Off topic discussion
Topic: Current news vs Pi production
Replies: 31
Views: 705

Re: Current news vs Pi production

My pi clearly says made in PRC. But it’s a pi 3b not a pi4. I assume you still produce pi 3 in China? I recall hearing (may be outdated), that all 3B+s had their final assembly and test in wales (though some had their SMT assembly done in Japan) due to more stringent test requirements. I would gues...
by plugwash
Thu Jan 23, 2020 12:46 am
Forum: Beginners
Topic: About Raspberry Pi 4
Replies: 11
Views: 588

Re: About Raspberry Pi 4

I think jahboater is confused. Above 32GB cards go from being SDHC to SDXC, AIUI there is no significant difference at the electrical or block protocol level but the default filesystem changes from FAT32 to exFAT, so the card needs to be reformatted before it can be used in a Pi. Above 2TB cards wil...
by plugwash
Tue Jan 21, 2020 6:38 pm
Forum: Troubleshooting
Topic: USB C power port fell off
Replies: 10
Views: 787

Re: USB C power port fell off

My feeling is if none of the pads were lifted then the soldering probably wasn't very good to start with. A good solder joint is normally stronger than the glue that holds the copper to the PCB substrate. Connectors are often problematic in soldering because they have a large thermal mass and so oft...
by plugwash
Tue Jan 21, 2020 6:33 pm
Forum: General discussion
Topic: RPi3 official PSU solved my problems. But why?
Replies: 15
Views: 970

Re: RPi3 official PSU solved my problems. But why?

Indeed depending on the inductor value and the power draw it could potentially take multiple cycles for current to ramp up or down. If the output capacitor is too small to absorb the maximum energy stored in the inductor (or transformer for an isolated supply) without causing an overvoltage on the o...
by plugwash
Sun Jan 19, 2020 1:41 pm
Forum: Troubleshooting
Topic: Raspberry pi 3 b+ wrong kernel with armv6l
Replies: 4
Views: 166

Re: Raspberry pi 3 b+ wrong kernel with armv6l

it may be hard to swallow, but I think the most likely answer is that you don't actually have a 3B+, but instead have a 1B+.
by plugwash
Sun Jan 19, 2020 1:10 am
Forum: General discussion
Topic: Future of raspberry pi - software related
Replies: 330
Views: 14290

Re: Future of raspberry pi - software related

I used windows for a few years on 640x480 (I bought a new PC, but kept my old monitor that I got with a secondhand 386), low res by modern standards, but I considered it perfectly usable at the time. I'm sure with some work a more modern desktop UI could be slimmed down to be usable on an 800x480 sc...
by plugwash
Thu Jan 16, 2020 4:08 pm
Forum: General discussion
Topic: Future of raspberry pi - software related
Replies: 330
Views: 14290

Re: Future of raspberry pi - software related

This is more firmware but could the Pi 4 bootcode initialise the HDMI output and display something if it can't access the card or read the files? Ideally it'd be an error message or icon. Same with the start*.elf firmware. Could it display something if something goes wrong? It would help troublesho...
by plugwash
Thu Jan 16, 2020 4:02 pm
Forum: General discussion
Topic: Future of raspberry pi - software related
Replies: 330
Views: 14290

Re: Future of raspberry pi - software related

Connecting new users with the forums is a nice idea. Even a standard menu of links to open the default browser on key forum stickies and other web resources could be helpful to new users. I do wonder how well the forum would cope though, it's currently at about 200K members. Afaict about 30 million...
by plugwash
Mon Jan 13, 2020 6:22 pm
Forum: General discussion
Topic: Future of raspberry pi - software related
Replies: 330
Views: 14290

Re: Future of raspberry pi

I don't see the RAM controller changing, as we are informed it can handle up to 16GB RAM...but the 8GB or 16GB packages don't exist in the form a Pi can use. I don't see it radically changing, but I could see there being tweaks to it if bugs show up during testing with larger ram chips. IIRC the or...
by plugwash
Mon Jan 13, 2020 5:28 pm
Forum: General discussion
Topic: Future of raspberry pi - software related
Replies: 330
Views: 14290

Re: Future of raspberry pi

As raspberry pi has grown they have gained the ability to be more ambitious. The original Pi was based on a SoC primerally designed for media boxes. For the pi2 and pi3 they persuaded broadcom to do a "cut and shut" job replacing the arm cores but leaving the rest of the SoC alone. For the Pi4 they ...
by plugwash
Fri Jan 10, 2020 11:36 pm
Forum: General discussion
Topic: Firefox security hole in 68.3
Replies: 5
Views: 481

Re: Firefox security hole in 68.3

It's building now.
by plugwash
Thu Jan 09, 2020 11:39 pm
Forum: General discussion
Topic: PCIe over cable standard. I didn't know that was a thing.
Replies: 22
Views: 894

Re: PCIe over cable standard. I didn't know that was a thing.

External PCIe is a "thing" in the sense that there are certain niche applications where it is used, either over standard or non-standard connectors (the cheap chinese stuff I have seen uses USB3 connectors), but it has never gone mainstream (and probablly never will).
by plugwash
Sat Jan 04, 2020 10:01 am
Forum: Networking and servers
Topic: Self-hosted, NAT-friendly IoT fleet management?
Replies: 10
Views: 390

Re: Self-hosted, NAT-friendly IoT fleet management?

A VPN doesn't have to involve "network infrastructure changes", you can just run a VPN server on the internet and then have all your Pis connect to it.
by plugwash
Sat Jan 04, 2020 9:57 am
Forum: General discussion
Topic: Is anyone really using dual 4k drivers on Rpi4?
Replies: 41
Views: 2147

Re: Is anyone really using dual 4k drivers on Rpi4?

I questioned who would actually need to power dual 4k video outputs on a raspberry pi. Dual display has a lot of uses, digital signage is an obvious application, desktop/thin client use is another, entertainment systems is another (small touchscreen for control, projectors or big screens for the pu...
by plugwash
Sat Jan 04, 2020 6:19 am
Forum: Raspbian
Topic: Broken Canadian Mirror muug.ca
Replies: 18
Views: 664

Re: Broken Canadian Mirror muug.ca

How come Canada is limited to Canadian mirrors, why not share the US mirrors? Technically speaking it isn't, if the mirror redirector doesn't find any canadian mirror with the file in question then it will use mirrors elsewhere, or even as a last resort send the file directly. The problem is that w...
by plugwash
Sat Jan 04, 2020 6:08 am
Forum: Raspbian
Topic: Broken Canadian Mirror muug.ca
Replies: 18
Views: 664

Re: Broken Canadian Mirror muug.ca

I have just disabled muug.ca's entry in the mirror redirection system, please get in touch when things are back to normal so I can re-enable it.
by plugwash
Fri Jan 03, 2020 10:36 pm
Forum: General discussion
Topic: OKdo power supply for Raspberry Pi 4
Replies: 3
Views: 231

Re: OKdo power supply for Raspberry Pi 4

As I understand it okdo is a brand/subsidary of Electrocomponents (who also operate under the names RS components and Allied electronics), one of the two main companies that make raspberry pis under license. I am pretty confident that the power supply you have linked is not an official raspberry pi ...
by plugwash
Tue Dec 31, 2019 10:51 am
Forum: Troubleshooting
Topic: what would happen if wire a 5V battery to the 5VDC gpio pins of a rasbary pi 4
Replies: 12
Views: 426

Re: what would happen if wire a 5V battery to the 5VDC gpio pins of a rasbary pi 4

The Pi will only draw the current it needs, but the voltage needs to be kept within a fairly narrow band (±5% is recommended) of the nominal 5V. Too high and there is a risk of damage, too low and the system may flake out. When undervoltage is detected the system will reduce the CPU speed (and hence...
by plugwash
Wed Dec 25, 2019 11:26 pm
Forum: General discussion
Topic: raspberry pi model b 1gb, 2gb, 4gb + 8gb variants?
Replies: 12
Views: 517

Re: raspberry pi model b 1gb, 2gb, 4gb + 8gb variants?

IIRC Eben has said that 8GB is theoretically supported by the SoC, but no suitable ram package was available.
by plugwash
Tue Dec 24, 2019 1:59 am
Forum: Advanced users
Topic: /dev/ttyAMA0 -> /dev/ttyS1
Replies: 18
Views: 831

Re: /dev/ttyAMA0 -> /dev/ttyS1

How devices are named seems to depend on who wrote the drivers and what conversions were at the time. Whoever wrote the driver for the arm AMBA uarts (long before the Pi became a thing) chose to use "ttyAMA", while whoever wrote the driver for the mini UART chose to use ttyS (the same as used for bu...
by plugwash
Tue Dec 24, 2019 1:13 am
Forum: HATs and other add-ons
Topic: how to sense 220v input -solved- I hope
Replies: 59
Views: 57018

Re: how to sense 220v input -solved- I hope

I am looking to sense 24VAC, a US thermostat call. I can use any optoisolator, but the LTV-844 stands out. (forward voltage=1.8V, forward current=50mA) 50mA is the absolute maximum rating. I doubt you will need to go anywhere near that high. 5mA is probablly far more reasonable. Normally you would ...
by plugwash
Sun Dec 22, 2019 2:57 am
Forum: Raspbian
Topic: libsdl2-dev cannot be installed
Replies: 2
Views: 342

Re: libsdl2-dev cannot be installed

Have you run apt-get update? if so did it complete without errors?

What is the contents of /etc/apt/sources.list.d/raspi.list ?
by plugwash
Thu Dec 19, 2019 11:41 pm
Forum: Beginners
Topic: Power to Raspberry Pi from UK 110v 16A on Construction Site
Replies: 8
Views: 426

Re: Power to Raspberry Pi from UK 110v 16A on Construction Site

Unless you have 400V single-phase sockets around (which are pretty rare) filing the tab off a blue CEEFORM to 13A socket adapter isn't really any more hazardous than any of the other options. Filing the tab off a yellow plug would obviously be a much worse sin.
by plugwash
Thu Dec 19, 2019 11:06 pm
Forum: Beginners
Topic: Power to Raspberry Pi from UK 110v 16A on Construction Site
Replies: 8
Views: 426

Re: Power to Raspberry Pi from UK 110v 16A on Construction Site

There are various possible solutions but all of them are sub-optimal in some way, and it may be wise to talk to whoever is responsible for safety on your site before you go ahead. One option is to buy or make an adapter lead to an american socket. However there are a couple of potential issues here,...

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