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by rurwin
Mon Mar 13, 2017 10:29 am
Forum: Off topic discussion
Topic: Snarky non-responses to questions - grumpy man ramblings
Replies: 252
Views: 36141

Re: Snarky non-responses to questions

So vi is the editor that has the greatest economy of finger movement so long as you remap the keys? I was an emacs man through and through but the last straw came in 2014 when they deleted the cookie recipes. jEdit all the way now. Key-only editors do have one disadvantage. A colleague once told me ...
by rurwin
Mon Mar 13, 2017 7:25 am
Forum: Off topic discussion
Topic: Snarky non-responses to questions - grumpy man ramblings
Replies: 252
Views: 36141

Re: Snarky non-responses to questions

Gavinmc42 wrote:Never could figure out why 101 keys, I only have 10 fingers.
Have you ever tried the Micro Writer? It might be extinct now but I am told it was great to use once you learned it.



4
by rurwin
Mon Mar 13, 2017 12:30 am
Forum: Off topic discussion
Topic: Snarky non-responses to questions - grumpy man ramblings
Replies: 252
Views: 36141

Re: Snarky non-responses to questions

Shift-AltGr+/u, you say?



Not on Linux (Ubuntu LTS) it's not.

@łe¶ŧ←↓→øþ
æßðđŋħł
«»¢“”nµ,·

Ah. AltGr+m

Trust Linux to be sensible and put mu under m. And I assume it's Microsoft that puts it under u because appearances are everything, right?


5
by rurwin
Sun Mar 12, 2017 12:44 pm
Forum: Troubleshooting
Topic: octoprint printing slow
Replies: 4
Views: 4056

Re: octoprint printing slow

I have a Pi3B talking to a SeeMeCNC Orion Delta. It works fine. So it is not the fault of the hardware. Can you take the Pi out of the loop and use a laptop with the same cable? That would show whether it was the printer or USB cable that was at fault. If that prints fast then we would have to think...
by rurwin
Sun Mar 12, 2017 12:28 pm
Forum: Off topic discussion
Topic: Snarky non-responses to questions - grumpy man ramblings
Replies: 252
Views: 36141

Re: Snarky non-responses to questions

Or just do a random Google and copy it from another website.

Or bring up a word-processor or a character map app.

Or say "fiddle it"; life's too short and no SI prefix is abbreviated "u".


6
by rurwin
Sun Mar 12, 2017 10:30 am
Forum: Off topic discussion
Topic: Snarky non-responses to questions - grumpy man ramblings
Replies: 252
Views: 36141

Re: Snarky non-responses to questions

If it is a white unicorn and is now pink then it has red shifted. Better get out of it's way it's moving fast. No need to worry; it's moving away from you. To my mind, the gun counts as an observer, let alone the cat or even the mouse. And anyone who has ever had a cat in a closed box (that it does...
by rurwin
Sat Mar 11, 2017 6:42 pm
Forum: Off topic discussion
Topic: Snarky non-responses to questions - grumpy man ramblings
Replies: 252
Views: 36141

Re: Snarky non-responses to questions

So how do you know the speed measuring device has taken its readings from the same part of the vehicle? The avg car length at 2.1metres is + or - 30mph's during the 0.3 second time period used to emit 3 laser pulses in order to calculate a speed reading. It uses doppler, not radar. All parts of the...
by rurwin
Sat Mar 11, 2017 1:54 pm
Forum: Off topic discussion
Topic: Snarky non-responses to questions - grumpy man ramblings
Replies: 252
Views: 36141

Re: Snarky non-responses to questions

If Johnny is not going directly towards the observer ie cop on the side of the road. Will it be exactly 325nm the cop sees? Can he then work out what speed Johnny is going? The only velocity that matters is that component that is radial to the cop. You can work it out with sines and cosines and Pyt...
by rurwin
Fri Mar 10, 2017 6:41 pm
Forum: Off topic discussion
Topic: Snarky non-responses to questions - grumpy man ramblings
Replies: 252
Views: 36141

Re: Snarky non-responses to questions

bensimmo wrote:Especially as an 850nm wave is infrared, so somebody made your red laser wrong, i would complain to the manufacturer.
:roll:


10
by rurwin
Fri Mar 10, 2017 6:04 pm
Forum: Off topic discussion
Topic: Snarky non-responses to questions - grumpy man ramblings
Replies: 252
Views: 36141

Re: Snarky non-responses to questions

In order to make sense in this "discussion" the observer has to be Johnny and he has to be observing the reflection of his red laser from the oncoming spaceship. Why is anyone confused by that? Now using a smattering of Special Relativity and Newton is all I'm capable of, but I make the relative vel...
by rurwin
Fri Mar 10, 2017 5:39 pm
Forum: Troubleshooting
Topic: USB ports not grounded?
Replies: 31
Views: 4807

Re: USB ports not grounded?

I can only imagine that the (only) reason why metal makes a difference is that it is a good conductor, as you do provide a sudden path to ground when you touch it with something conductive. Another possibility is that the metal object acts as an aerial and injects a large RF voltage onto the ground...
by rurwin
Fri Mar 10, 2017 1:34 pm
Forum: General discussion
Topic: Run raspberrypi for Long Duration
Replies: 17
Views: 3077

Re: Run raspberrypi for Long Duration

I've got a Pi 3B at the moment running OctoPi. I don't bother switching it off. So at this point it's probably been running for a month or so. Generally the only reasons to reboot a Pi is for a Linux kernel update, which are rare and optional, or because I've forgotten the command to restart a servi...
by rurwin
Fri Mar 10, 2017 1:28 pm
Forum: General discussion
Topic: Headless programming while hosting USB device
Replies: 7
Views: 1126

Re: Headless programming while hosting USB device

I don't know.

Does the Pi Zero use the swapped UARTs even though there's no Bluetooth? I hope not, but it might.

Or the OP might have ment that he had a Pi Zero W.
by rurwin
Fri Mar 10, 2017 10:14 am
Forum: Off topic discussion
Topic: Snarky non-responses to questions - grumpy man ramblings
Replies: 252
Views: 36141

Re: Snarky non-responses to questions

Imagine the cop was a long, long way from the road. The distance between him and the car would mainly be the distance between him and the car; the car's movement would make little difference to the distance between them and therefore the speed he measured would be smaller. IIUC, dopler shift in ligh...
by rurwin
Fri Mar 10, 2017 9:52 am
Forum: General discussion
Topic: 433 MHz in python.
Replies: 9
Views: 3874

Re: 433 MHz in python.

I'm tempted to delete a few posts to tidy this thread up, but I won't. Just let it drop now, all of you. jondallimore, the "learn to read" was uncalled for and against the rules of this forum. Heater, a little more verbose and less confrontational first answer might have helped. In addition "433MHz ...
by rurwin
Thu Mar 09, 2017 12:32 pm
Forum: General discussion
Topic: Headless programming while hosting USB device
Replies: 7
Views: 1126

Re: Headless programming while hosting USB device

(Edit: I was mistaken so I've corrected this post.) The GPIO UART is now a different one due to one being needed for Bluetooth, but that causes problems because the baud rate changes with the processor clock. The processor clock slows down if the Pi is getting hot and maybe if it isn't heavily loade...
by rurwin
Thu Mar 09, 2017 8:51 am
Forum: Troubleshooting
Topic: USB ports not grounded?
Replies: 31
Views: 4807

Re: USB ports not grounded?

Earthing is a dark art. Get it wrong and you end up with more problems than if you don't do it. Generally the answer is that you should have exactly one earth point for everything. If your Pi is earthed through the HDMI lead, then that is all you need or should have. It is a feature of most of the P...
by rurwin
Tue Mar 07, 2017 3:52 pm
Forum: Automation, sensing and robotics
Topic: Connecting a Pi to about 100 push buttons
Replies: 30
Views: 4956

Re: Connecting a Pi to about 100 push buttons

Personally, I would worry that button presses would be missed, due to the person just swiping the button quickly and the Pi scanning some other part of the matrix, or just not happening to read that button at that particular moment. I imagine you would want a system that was demonstrably fair to you...
by rurwin
Sun Mar 05, 2017 1:45 pm
Forum: Beginners
Topic: Photo resistance value
Replies: 2
Views: 682

Re: Photo resistance value

There's a couple of issues with that code. Firstly if your program gets interrupted by something else, then the count will be suspended for a while and the result will be low. It would be far better to remember the time at the beginning of the loop and the end of the loop and subtract the two. Secon...
by rurwin
Fri Mar 03, 2017 11:56 am
Forum: Automation, sensing and robotics
Topic: GPIO output wire length limits?
Replies: 18
Views: 4587

Re: GPIO output wire length limits?

To get cables across to the Queen Victoria Memorial in the Mall, we used a ferret. But I don't think a ferret would fit through a 10mm pipe Time to train a cockroach? I looked into this a while ago. I could find no relays of any type that could be used directly on the GPIO. With 5V logic you can do...
by rurwin
Thu Mar 02, 2017 4:26 pm
Forum: Automation, sensing and robotics
Topic: Consumable Stock Control
Replies: 4
Views: 707

Re: Consumable Stock Control

You'll need more than an Excell file. A Barcode scanner is generally seen by the computer as a keyboard. All it does is "type" the code on the barcode into the computer. If you scan the existing barcode on your consumable then you will just see a numeric string (which is also printed under the barco...
by rurwin
Thu Mar 02, 2017 10:29 am
Forum: Other projects
Topic: Designing a Printed Circuit Board on a Raspberry Pi
Replies: 8
Views: 4665

Re: Designing a Printed Circuit Board on a Raspberry Pi

Diptrace only seems to work on Linux using WINE. It therefore won't work on the Raspberry Pi. (Without using an x86 emulator, but using one would almost certainly make it horrendously slow.) I've been using gEDA recently, and I must say getting the footprints to match up with the components, and fin...
by rurwin
Thu Mar 02, 2017 9:50 am
Forum: Raspbian
Topic: What should i do with 99-com.rules?
Replies: 1
Views: 836

Re: What should i do with 99-com.rules?

In these cases, when you don't think you've changed anything in that file, it's generally safe to take the new version of the file. This is complicated in this instance because it isn't immediately obvious what the file does. However a quick Google of the file name found this: http://raspberrypi.sta...
by rurwin
Wed Mar 01, 2017 1:35 pm
Forum: Off topic discussion
Topic: Old School Fault Finding
Replies: 44
Views: 5435

Re: Old School Fault Finding

Incredible! 500cps paper tape reader. Never seen such a fast tape reader. The ultimate development of that design (Used by Elliotts on the 4100 range and ICL on the 1900 range) ran at 1000 cps. I've never seen one working :-( Nor have I but some guys when I was at school around 1976ish went on a fi...
by rurwin
Tue Feb 28, 2017 8:50 pm
Forum: General discussion
Topic: PI Zero W info
Replies: 80
Views: 12993

Re: PI Zero W info

By the way, what vendors and what machines exactly? He already answered that: We moved to the NanoPi NEOs - Quad CPU, 1.2Ghz, Tbase100, USB, OTG, MicroSD. This makes a good headless controller and by adding a SPI display we're good. We can buy quantity numbers without an issue. Production of the Ze...

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