Go to advanced search

by jahboater
Thu Apr 06, 2017 5:41 pm
Forum: General discussion
Topic: Hello... Where do I start, what are stickies?
Replies: 8
Views: 1746

Re: Hello

texy wrote:Hi and welcome to the forum.
That just really means to check if your specific problem hasn't already been address in one of the sickies, or other threads.
Perhaps "stickies"!
by jahboater
Thu Apr 06, 2017 5:34 pm
Forum: Staffroom, classroom and projects
Topic: Stabilizing RPi3 speed for my classes
Replies: 10
Views: 5311

Re: Stabilizing RPi3 speed for my classes

I modify the file and check the content (cat boot/config.txt). Everything seems OK. If I eject the sdcard and plug it in again, the file shows the original content. No modification. Perhaps type "sync" and/or properly unmount the filesystem before ejecting the card. You must not simply pull the car...
by jahboater
Thu Apr 06, 2017 5:09 pm
Forum: Teaching and learning resources
Topic: ARM assembly textbook suggestions
Replies: 2
Views: 2564

Re: ARM assembly textbook suggestions

Hello everyone, Which book would you suggest to learn ARM assembly? I'm looking at ARM Assembly Language: Fundamentals and Techniques, Second Edition by William Hohl & Christopher Hinds. It seems like a good book but it's center around ARM7 and not ARMv8 like the rp3. I have that book, and I can re...
by jahboater
Thu Apr 06, 2017 12:56 pm
Forum: General discussion
Topic: Overheating dangers between RP2 vs RP3
Replies: 27
Views: 3365

Re: Overheating dangers between RP2 vs RP3

Also, please ignore the usual conspiracy theories about Wifi 'radiation' being bad for you. It isn't. You get more ionising radiation from a human body due to the decay of C14 than you do from a wireless router. Its probably the heating effect people (needlessly) worry about. 2.4GHz is close to the...
by jahboater
Thu Apr 06, 2017 11:37 am
Forum: General discussion
Topic: Overheating dangers between RP2 vs RP3
Replies: 27
Views: 3365

Re: Overheating dangers between RP2 vs RP3

Or simply provide a way of powering off the Wifi chip from within raspi-config.
Cheaper than two separate products.

I keep my seeds in the garden shed, so I'm OK ...
by jahboater
Thu Apr 06, 2017 10:54 am
Forum: General discussion
Topic: Overheating dangers between RP2 vs RP3
Replies: 27
Views: 3365

Re: Overheating dangers between RP2 vs RP3

What does the cpuburn utility do, exactly ? It runs some NEON SIMD instructions on all four cores (I think its doing at least 16 operations per cycle maybe more because NEON is now quad issue). I have found it heats up the CPU quicker than anything else. You can examine the code in cpuburn-a53.S Wh...
by jahboater
Thu Apr 06, 2017 10:12 am
Forum: General discussion
Topic: Overheating dangers between RP2 vs RP3
Replies: 27
Views: 3365

Re: Overheating dangers between RP2 vs RP3

It turns out there are lots and lots of videos on youtube where people do their own experiments, using utilities like sysbench, to figure out how hot the RP3 gets. The answer is... over 80 degrees in 5 to 10 minutes ! Try this ... wget https://raw.githubusercontent.com/ssvb/cpuburn-arm/master/cpubu...
by jahboater
Thu Apr 06, 2017 8:04 am
Forum: Raspberry Pi OS
Topic: Raspbian Jessie
Replies: 2
Views: 652

Re: Raspbian Jessie

In fact, I have seen some references that indicate that Raspbian Jessie automatically places /var/run in RAM upon boot. Please tell me if in fact that is what Raspbian Jessie does, does this mean that MySQL's socket communications are actually already occurring in RAM and if so is what I am attempt...
by jahboater
Thu Apr 06, 2017 7:32 am
Forum: General discussion
Topic: Re-formatting the SD card
Replies: 25
Views: 118529

Re: Re-formatting the SD card

If you don't need noobs, simply put the new OS on the card without formatting it first. https://www.raspberrypi.org/downloads/raspbian/ and follow the instructions (which work on Windows, Mac, or Linux - probably easiest on Linux as the tools are standard). There is never any need to delete partitio...
by jahboater
Wed Apr 05, 2017 11:00 am
Forum: General discussion
Topic: Overheating dangers between RP2 vs RP3
Replies: 27
Views: 3365

Re: Overheating dangers between RP2 vs RP3

I'm interested by your suggestion that the life-span of the Pi might be measured in decades. RP's are new devices... so there can't be empirical evidence. Where did you read this idea ? Do you have a link to that ? Thanks again for your help :) Various quotes from RPF engineers over the years. Orig...
by jahboater
Wed Apr 05, 2017 10:34 am
Forum: HATs and other add-ons
Topic: Misconceptions about WiFi Antenna
Replies: 3
Views: 652

Re: Misconceptions about WiFi Antenna

There are several things wrong with those statements. Changing the antenna does not "increases the transmit radiated power", the antenna is passive, only an amplifier can increase the transmitted power. It might increase the Effective Isotropic Radiate Power (eirp) but that is not the same thing ! ...
by jahboater
Wed Apr 05, 2017 9:16 am
Forum: General discussion
Topic: Memory expansion for RP2 / RP3
Replies: 7
Views: 1155

Re: Memory expansion for RP2 / RP3

If you do get short of memory, there is a Lite version of Rasbian with no GUI (often used for headless installations) that is rather smaller.
by jahboater
Wed Apr 05, 2017 9:03 am
Forum: General discussion
Topic: Memory expansion for RP2 / RP3
Replies: 7
Views: 1155

Re: Memory expansion for RP2 / RP3

Hi there, just a quick question concerning the possibility of expanding the memory on the RP2 and/or RP3. Are there any reasons why i couldn't expand the memory to 2 gig or 4 gig ? For example firmware limitations or chip specifications or space or on the RP board ? No (chip limits). Why do you nee...
by jahboater
Wed Apr 05, 2017 8:45 am
Forum: General discussion
Topic: Overheating dangers between RP2 vs RP3
Replies: 27
Views: 3365

Re: Overheating dangers between RP2 vs RP3

The new Pi2 (v1.2) has the same ARMv8 based SoC as the Pi3 but is clocked at 900Mhz instead of 1.2GHz for the Pi3. You are free to downclock the Pi3 to any speed you like. In any case the Pi's lifetime is measured in decades. The Pi will protect itself by progressively throttling the clock speed bac...
by jahboater
Wed Apr 05, 2017 7:47 am
Forum: Raspberry Pi OS
Topic: Raspian easy install. Instant networking and SSH.
Replies: 8
Views: 1622

Re: Raspian easy install. Instant networking and SSH.

I installed a fresh Raspian today using your instructions. Wifi and SSH instantly up. Your prescription should really be part of the official installation instructions. Thanks again H Well done! If your PC runs Linux, then you can mount the second ext4 partition and make any changes you like to tha...
by jahboater
Tue Apr 04, 2017 10:13 pm
Forum: Beginners
Topic: What to buy? [Beginner]
Replies: 6
Views: 696

Re: What to buy? [Beginner]

Another possibility might be GPS which I believe would give you extremely accurate time.
by jahboater
Tue Apr 04, 2017 10:10 pm
Forum: HATs and other add-ons
Topic: Amplify onboard wireless adapter
Replies: 7
Views: 1347

Re: Amplify onboard wireless adapter

Wifi radio is a two way thing. If you increase the transmit power, the other side may hear you better. But unless the other side also increases their transmit power, you will not hear them and it still wont work. Best to improve the antenna which increases both the transmit radiated power and the re...
by jahboater
Tue Apr 04, 2017 6:40 pm
Forum: General discussion
Topic: Pi Zero W Antenna Mod Suggestion (Plea in fact)
Replies: 13
Views: 2055

Re: Pi Zero W Antenna Mod Suggestion (Plea in fact)

*Any* modification that changes the emissions profile of a board would put it out of compliance with its FCC/CE certifications. So how does this work with the better USB WiFi adapters that have a detachable antenna and an SMA socket? The end user is presumably *expected* to change the antenna for o...
by jahboater
Tue Apr 04, 2017 6:19 pm
Forum: Beginners
Topic: What to buy? [Beginner]
Replies: 6
Views: 696

Re: What to buy? [Beginner]

And--FYI--isn't changing the display every half hour a bit...low resolution...for a clock. Once a minute, sure, but every half hour? Just to add to that, updating the display once per second is trivially easy for the Raspberry Pi, its processor is far far more powerful than the circuitry in a clock...
by jahboater
Tue Apr 04, 2017 6:06 pm
Forum: Beginners
Topic: What to buy? [Beginner]
Replies: 6
Views: 696

Re: What to buy? [Beginner]

I'm new to Raspberry Pi and I'm in need of help with buying correct parts. I'm looking for parts to build a small programmable clock display that changes time every half an hour. What parts will I need and which Raspberry Pi should I get? Thanks in advance. How about this ? https://thepihut.com/col...
by jahboater
Tue Apr 04, 2017 9:55 am
Forum: Python
Topic: Suggested Python IDE?
Replies: 8
Views: 10982

Re: Suggested Python IDE?

I'm assuming that SSH is the only option (Although read something about VNC and a virtual desktop that I might look into). VNC is included with Raspbian and just needs to be enabled in raspi-config/interfacing options. That gives you the PIXEL desktop on your PC. I was hoping to create/edit python ...
by jahboater
Tue Apr 04, 2017 7:50 am
Forum: Off topic discussion
Topic: What is your current PC/OS
Replies: 69
Views: 18699

Re: What is your current PC/OS

I saw this https://techcrunch.com/2017/04/03/statc ... d-windows/ (android is Linux).

Personally, I use Linux on all my machines. I do have a Windows 7 laptop, but its only been turned on once in the last few years, and then only to check it still worked!
by jahboater
Sat Apr 01, 2017 11:03 am
Forum: Troubleshooting
Topic: Capturing Program Output in a Variable
Replies: 5
Views: 1180

Re: Capturing Program Output in a Variable

For shell scripts I use dash - as its name suggests its lightweight and very fast POSIX shell.

#!/bin/dash
by jahboater
Fri Mar 31, 2017 8:41 am
Forum: General discussion
Topic: Just a few Questions
Replies: 5
Views: 1075

Re: Just a few Questions

There are many ways to start a program on bootup, The best/most flexible way will be via systemd for which you should be able to find many examples on this forum. Other options include adding it to the rc.local script or using cron's @reboot target. Or adding init=<myprogram> to /boot/cmdline.txt w...

Go to advanced search