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by PeterO
Thu Feb 20, 2020 9:49 am
Forum: Python
Topic: What is the difference between...
Replies: 18
Views: 398

Re: What is the difference between...

gordon77 wrote:
Thu Feb 20, 2020 9:34 am
Cheers, I read https://matplotlib.org/3.1.1/api/animation_api.html but I couldn't see the difference between import / from.
Why would the python import statement be documented there ? :roll:
Try reading https://docs.python.org/3/reference/sim ... tml#import
PeterO
by PeterO
Thu Feb 20, 2020 8:41 am
Forum: Python
Topic: Vulkan Question
Replies: 1
Views: 46

Re: Vulkan Question

No,

Vulkan is a replacement for openGL See https://en.wikipedia.org/wiki/Vulkan_(API)

PeterO
by PeterO
Wed Feb 19, 2020 12:18 pm
Forum: Picademy
Topic: Raspberry Pi Certified Educator program in 2020?
Replies: 3
Views: 266

Re: Raspberry Pi Certified Educator program in 2020?

fruitoftheloom wrote:
Wed Feb 19, 2020 11:58 am
starworks26 wrote:
Wed Jan 15, 2020 8:32 pm
Hi,
I want to do a Raspberry Pi Certified Educator course in United Kingdom. Anybody knows dates and details?

Thanks,
SW26

https://www.raspberrypi.org/training/picademy/rce/
But the events calendar seems to either be broken or empty !
PeterO
by PeterO
Wed Feb 19, 2020 11:40 am
Forum: Other programming languages
Topic: Introduction to BBC BASIC
Replies: 606
Views: 59040

Re: Introduction to BBC BASIC

I think it may have been due to hardware capabilities. The Envelope function (IIRC) was a feature of the sound chip used on the BBC Micro. I don't believe that's right. My understanding is that ENVELOPE was implemented entirely in software, i.e. in the BBC Micro's MOS, not in the sound chip. If you...
by PeterO
Wed Feb 19, 2020 7:41 am
Forum: Beginners
Topic: Fan on GPIO 17 not working
Replies: 9
Views: 174

Re: Fan on GPIO 17 not working

There is no need for a scrip.. https://www.raspberrypi.org/forums/viewtopic.php?t=249624 PeterO I know only use the Crontab so i create a script for this job? How your command is running on boot? It's not a command, it's a device tree overlay configuration line that goes in /boot/config.txt PeterO
by PeterO
Wed Feb 19, 2020 7:29 am
Forum: Beginners
Topic: Fan on GPIO 17 not working
Replies: 9
Views: 174

Re: Fan on GPIO 17 not working

i have implemented the fan command with resistor, transistor NPN 8050, protection Diode for cooling the pi4 with a script that command the fan when temperature is upper than 40°C, if you want tutorial There is no need for a scrip.. https://www.raspberrypi.org/forums/viewtopic.php?t=249624 PeterO
by PeterO
Fri Feb 14, 2020 3:28 pm
Forum: Troubleshooting
Topic: [Solved] Overcoming a GCC 'sudo' issue
Replies: 5
Views: 147

Re: Overcoming a GCC 'sudo' issue

I downloaded it and I now see what you mean. ~/armhf-zpu-elf-gcc-3.4.2/bin $ strings zpu-elf-gcc | grep root ../gcc/configure --target=zpu-elf --prefix=/root/Downloads/zpugcc/toolchain/gccbuild/../install --enable-languages=c,c++ --with-gnu-as --with-gnu-ld --with-newlib --disable-shared --enable-ne...
by PeterO
Fri Feb 14, 2020 2:59 pm
Forum: Troubleshooting
Topic: [Solved] Overcoming a GCC 'sudo' issue
Replies: 5
Views: 147

Re: Overcoming a GCC 'sudo' issue

Are you sure you wern't running as root when did the untar step ?

I can't see how the files could have got into /root unless you were running as root.

PeterO
by PeterO
Fri Feb 14, 2020 1:35 pm
Forum: General discussion
Topic: TONS of RAM being used?
Replies: 19
Views: 600

Re: TONS of RAM being used?

If it's suffering topic drift , note that it was you that first mentioned "killall"...
I ran killall yad while debugging a command,
PeterO
by PeterO
Fri Feb 14, 2020 1:17 pm
Forum: General discussion
Topic: TONS of RAM being used?
Replies: 19
Views: 600

Re: TONS of RAM being used?

dickon wrote:
Fri Feb 14, 2020 12:41 pm
Run killall on some operating systems, and you're in for a bit of a shock.

pkill does the same thing everywhere. killall does not.
Sorry, but the day isn't long enough to worry about what a particular command does on OS'es that I don't use !
PeterO
by PeterO
Fri Feb 14, 2020 11:26 am
Forum: Raspbian
Topic: Screen blanks when clock updates
Replies: 2
Views: 87

Re: Screen blanks when clock updates

It's obviously not a bug and it is obvious what it is doing and why. As I explained at length..... Still, it can be a little jarring. No big deal, but are you really actually talking about "the demo effect" - that if you are showing this to non-techy people, they ask "Why does it do that?" and it l...
by PeterO
Fri Feb 14, 2020 10:59 am
Forum: Troubleshooting
Topic: Can't copy files form RPi using scp
Replies: 14
Views: 205

Re: Can't copy files form RPi using scp

scp needs a source and a destination. From and To . You have only specified one. So the help message is trying to point out how to use it... According to this manual: https://www.raspberrypi.org/documentation/remote-access/ssh/scp.md there is no need to specify destination. Destination folder shoul...
by PeterO
Fri Feb 14, 2020 10:47 am
Forum: Raspbian
Topic: Screen blanks when clock updates
Replies: 2
Views: 87

Screen blanks when clock updates

Shortly after the fist boot of the day the clock is updated via the network . This morning for example the time went from 22:43 10:45.

This triggers the screen save timeout and blanks the screen. It's not a major probelm but it is annoying and kind of looks like a bug.

PeterO
by PeterO
Fri Feb 14, 2020 8:11 am
Forum: Beginners
Topic: Wiring inductive sensors in series
Replies: 38
Views: 710

Re: Wiring inductive sensors in series

Just a thought, You've not mentioned how far the sensors are from the PI, but if they are more than a few centimetres apart I would consider running the 5V out to the sensors and the return signal in some screened cable. I would use stereo audio cable, both outers connected to 0V, 5V on one inner an...
by PeterO
Thu Feb 13, 2020 11:47 pm
Forum: Beginners
Topic: Wiring inductive sensors in series
Replies: 38
Views: 710

Re: Wiring inductive sensors in series

boyoh wrote:
Thu Feb 13, 2020 11:35 pm
It is only the out put transistors that are connected in series
And as explained earlier, therein lies the potential problem ! Vsat could be in the order of 400mV, so you've lost 2.4V across six of them.
PeterO
by PeterO
Thu Feb 13, 2020 11:39 pm
Forum: General discussion
Topic: TONS of RAM being used?
Replies: 19
Views: 600

Re: TONS of RAM being used?

dickon wrote:
Thu Feb 13, 2020 11:32 pm
pkill. Please, for the love of the gods, pkill...
Yeah, because nothing ever goes wrong with pattern matching :lol: :roll:
PeterO
by PeterO
Thu Feb 13, 2020 1:28 pm
Forum: Beginners
Topic: Wiring inductive sensors in series
Replies: 38
Views: 710

Re: Wiring inductive sensors in series

neilgl wrote:
Thu Feb 13, 2020 1:10 pm
Maybe avoid using GPIO2 and GPIO3 as they have the fixed, 1.8 kΩ pull-up to 3.3v ?
Yes, avoid these pins. I never use them for I/O in my projects as I often use I2C or SPI that's why I hadn't noticed they were being used here.
PeterO
by PeterO
Thu Feb 13, 2020 10:23 am
Forum: Beginners
Topic: Wiring inductive sensors in series
Replies: 38
Views: 710

Re: Wiring inductive sensors in series

Looks good. The only thing I would do differently is to use 2k2Ω and 3k3Ω in the voltage divider. Why ? 1) 5 * 3.3/5.5 = 3V which will give better noise immunity that 2.5V. 2) It draws less current from the 5V, current that ultimately ends up as heat in the resistors. Using 500Ω+500Ω the maximum dis...
by PeterO
Thu Feb 13, 2020 9:18 am
Forum: Beginners
Topic: Wiring inductive sensors in series
Replies: 38
Views: 710

Re: Wiring inductive sensors in series

ShortCircuit.png
ShortCircuit.png (45.08 KiB) Viewed 100 times
The basic idea is good, but there are a few extra connections you don't need !
PeterO
by PeterO
Thu Feb 13, 2020 8:00 am
Forum: OpenGLES
Topic: Current "work in progress"
Replies: 7
Views: 1072

Re: Current "work in progress"

https://twitter.com/PeterOnion/status/1 ... 3142768640
Crude "collision avoidance" implemented :-)
PeterO
by PeterO
Wed Feb 12, 2020 8:51 pm
Forum: OpenGLES
Topic: Current "work in progress"
Replies: 7
Views: 1072

Re: Current "work in progress"

WG20.png I've now got a pair on hands working. The picture above shows (with green crosses) the vertices I'm using to detect when the hands are touching. The line is being drawn between the two nearest vertices. Now I need to workout which are the most important vertices so I can reduce the number....
by PeterO
Wed Feb 12, 2020 8:19 pm
Forum: Beginners
Topic: Wiring inductive sensors in series
Replies: 38
Views: 710

Re: Wiring inductive sensors in series

It doesn't matter if I know which sensor is not closing as it is easy to see physically. The purpose of the sensors is just to activate the printer which can't be done unless all 6 are active or would this be cleaner to do through programming. Unless you mean to pick up faults in the wiring or comp...
by PeterO
Wed Feb 12, 2020 7:20 pm
Forum: Beginners
Topic: Wiring inductive sensors in series
Replies: 38
Views: 710

Re: Wiring inductive sensors in series

You really need to follow the link that the OP gave No, I don't 'need' to follow any links at all and would have to be considerably more motivated to do so. If OPs don't bother to attach specs I'm not going to bother hunting them down. You might be right about not understanding details. It's been a...
by PeterO
Wed Feb 12, 2020 6:30 pm
Forum: Beginners
Topic: Wiring inductive sensors in series
Replies: 38
Views: 710

Re: Wiring inductive sensors in series

No interface at all. Specially no opto or relays. Just connect to parallel port on the Pi. A load resistor and maybe divider if outputs are over 4v but mine were not so that was not needed. I did not have time to hunt down specs for your specific part but if they work like industry standard they in...
by PeterO
Wed Feb 12, 2020 10:52 am
Forum: General discussion
Topic: Reasoning behind dual Micro HDMI, and potential future alternatives?
Replies: 125
Views: 9983

Re: Reasoning behind dual Micro HDMI, and potential future alternatives?

jamesh wrote:
Wed Feb 12, 2020 10:39 am
It really is as simple as that.
I'm sure someone will argue otherwise :lol:
PeterO

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