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by jbeale
Tue Apr 17, 2012 6:16 pm
Forum: Troubleshooting
Topic: USB bus seems to be shutting down after 30seconds
Replies: 93
Views: 14080

Re: USB bus seems to be shutting down after 30seconds

<r>From what I"ve read elsewhere, these symptoms could be caused by low voltage on the Pi board, causing it to drop out when a higher-power device draws current from the RasPi USB host port, and/or the ethernet chip is trying to drive the cable, and/or the CPU in the SoC draws more current.<br/> <br...
by jbeale
Tue Apr 17, 2012 5:16 pm
Forum: Other projects
Topic: Raspberry Pi in space! Need advice :)
Replies: 25
Views: 5590

Re: Raspberry Pi in space! Need advice :)

<r>jbeale said: <br/> <br/> <br/> even a WiFi link can go fairly long range when unobstructed<br/> <br/> <br/> whoops, looks like a few km is the most you can expect with a simple WiFi dongle and small parabolic reflector. Although World Record distance is > 300 km (!) using a 35 dBi waveguide.  See...
by jbeale
Tue Apr 17, 2012 5:02 pm
Forum: Other projects
Topic: Raspberry Pi in space! Need advice :)
Replies: 25
Views: 5590

Re: Raspberry Pi in space! Need advice :)

<r>A lot of people have done weather balloon projects of this type, and you can find some documentation online which may help you get going in the right direction. If you are a licensed radio amateur (ham) that gives you additional radio options, but even a WiFi link can go fairly long range when un...
by jbeale
Tue Apr 17, 2012 4:19 am
Forum: Off topic discussion
Topic: Geek, nerd or boffin?
Replies: 29
Views: 5296

Re: Geek, nerd or boffin?

When my 6th grade science fair project got a mention in the local paper, I got called "geek" and "egghead" by classmates. I was amused to hear the latter term which I'd seen in print, but never actually heard spoken before, and seldom since.
by jbeale
Tue Apr 17, 2012 3:58 am
Forum: General discussion
Topic: Frambozenbier - The raspberry homebrew community
Replies: 45
Views: 8611

Re: Frambozenbier - The raspberry homebrew community

<r>Speaking just for myself, I want to thank the folks behind the frambozenbier site for some nicely organized information. The new "data sheets" look very spiffy.  I'd seen much of that before from <URL url="http://elinux.org/R-Pi_Hub">http://elinux.org/R-Pi_Hub</URL> but the datasheet format is cl...
by jbeale
Sun Apr 15, 2012 11:28 pm
Forum: Beginners
Topic: Power Explanation
Replies: 15
Views: 5415

Re: Power Explanation

<t>for how long in hours would it last, are you asking for MTBF (mean time before failure) that is, expected device lifetime before something breaks?<br/> <br/> Normally such single-board computers last longer than anyone is interested in using them. The failures that happen are usually connectors w...
by jbeale
Sun Apr 15, 2012 7:59 pm
Forum: General discussion
Topic: Pi Strengths
Replies: 2
Views: 734

Re: Pi Strengths

<t>rmm200 said: <br/> <br/>  There are simply more appropriate boards in about the same price range for many embedded applications.<br/> <br/> Actually, if you could point me to a $35 board with equivalent CPU, 256 MB SDRAM, 2 USB ports and Ethernet, as well as SD card, even with no GPU, I'd be inte...
by jbeale
Sun Apr 15, 2012 4:06 pm
Forum: Beginners
Topic: su password and bits and bobs
Replies: 20
Views: 84217

Re: su password and bits and bobs

<t>Joe Schmoe said: <br/> <br/> <br/> If that (*) is true, then it begs the question as to why there is a GUI at all.<br/> <br/> <br/> I think if you use a "light" desktop (LXDE) and applications that are designed for slower CPUs, it will be a lot more usable than just throwing the latest everything...
by jbeale
Sun Apr 15, 2012 3:36 pm
Forum: General discussion
Topic: RPi Addon boards
Replies: 17
Views: 3741

Re: RPi Addon boards

<t>I believe the largest bandwidth interface available is the USB port (internally also shared with ethernet port).  Given that, the best way to connect any significant external resources is through USB.  You can certainly connect a USB hard drive (though a USB hub to provide the power). I guess you...
by jbeale
Sun Apr 15, 2012 3:26 pm
Forum: General discussion
Topic: First post from a Raspberry Pi ?
Replies: 3
Views: 828

Re: First post from a Raspberry Pi ?

Does a twitter post count? There was one yesterday...

https://twitter.com/#!/CrostonBen
by jbeale
Sun Apr 15, 2012 3:11 pm
Forum: Beginners
Topic: su password and bits and bobs
Replies: 20
Views: 84217

Re: su password and bits and bobs

<t>Boreatton Scouts said:<br/> <br/> <br/> so main thing now is to get wifi and bluetooth and get office software as a basic PC setup...<br/> <br/> <br/> I'll be curious to know if you find the Pi is really usable for office software applications. Maybe it will be ok if you use stripped-down program...
by jbeale
Sun Apr 15, 2012 2:53 pm
Forum: Beginners
Topic: General Purpose Input and Output
Replies: 11
Views: 4852

Re: General Purpose Input and Output

<r>First, note that the GPIO pins use 3.3V logic level, and are intended to connect to digital logic gate inputs. They probably cannot drive enough current for a speaker directly, so you'll want an audio amplifier or some kind of driver circuit for the buzzer.<br/> <br/> I have not seen any example ...
by jbeale
Sun Apr 15, 2012 6:03 am
Forum: HATs and other add-ons
Topic: simple 16 signal GPIO I2C board
Replies: 31
Views: 17315

Re: simple 16 signal GPIO I2C board

This I2C based I/O expander board looks quite useful, I think I might like to get one for use with other devices, even before my RiPi arrives (which may be months, as I haven't yet even been able to order it).  Will look forward to seeing your board available for sale!
by jbeale
Sun Apr 15, 2012 4:56 am
Forum: General discussion
Topic: An Interesting Video of Eben
Replies: 3
Views: 848

Re: An Interesting Video of Eben

<t>It is visible only briefly, but the RS guy in a black short-sleeve shirt holding the board is wearing three separate bands on his right arm. One of them might be an ESD strap. There are other possible ESD precautions such as conductive mats, conductive shoes, ionized air streams, etc. When I visi...
by jbeale
Fri Apr 13, 2012 6:24 pm
Forum: Other projects
Topic: Cases for the Raspberry Pi
Replies: 866
Views: 382030

Re: Cases for the Raspberry Pi

<t>GizmoB73 said: <br/> <br/> <br/> After an hour with the lid on the SoC is measuring 48.7C and still running fine.<br/> <br/> <br/> If that's the hottest chip, sounds like everything should be OK. However, if it gets hotter when it's doing more computations (likely) and/or you want to run in a hot...
by jbeale
Fri Apr 13, 2012 5:46 am
Forum: Other projects
Topic: timer resolution (measuring pulse width)
Replies: 6
Views: 2683

Re: timer resolution (measuring pulse width)

<t>So my next question is: where can I learn about what interrupts may be active at any given time as Linux runs on the RasPi? And is there a way I can turn all of them off for a while, assuming I don't care about responding to any external I/O (ethernet, USB, GPU etc) during that time?<br/> <br/> N...
by jbeale
Fri Apr 13, 2012 5:39 am
Forum: Other projects
Topic: timer resolution (measuring pulse width)
Replies: 6
Views: 2683

Re: timer resolution (measuring pulse width)

<r>To answer my own question: according to p.199 of the RPi SoC peripherals datasheet here: <URL url="http://www.raspberrypi.org/wp-.....herals.pdf">http://www.raspberrypi.org/wp-.....herals.pdf</URL><br/> <br/> the ARM has one 32-bit free-running timer, which increments continually when bit 9 of th...
by jbeale
Fri Apr 13, 2012 12:27 am
Forum: Other projects
Topic: timer resolution (measuring pulse width)
Replies: 6
Views: 2683

Re: timer resolution (measuring pulse width)

<t>I know a little about Linux, but very little about ARM architectures. Suppose I have a pulse coming in on a GPIO pin and I want to measure the pulse width. Can anyone say what the best timer resolution is? And would this be directly linked to some fixed system clock frequency, or is it something ...
by jbeale
Thu Apr 12, 2012 4:28 am
Forum: Automation, sensing and robotics
Topic: Raspi-powered seismometer/seismograph
Replies: 63
Views: 37055

Re: Raspi-powered seismometer/seismograph

<t>A while ago, for fun I made a horizontal seismograph (swinging-door type)  out of wood, a copper coil, and magnets from a hard drive. The period was a few seconds. Problem is I live in an urban area and almost all the signal was from traffic outside, A/C in the building, etc.<br/> <br/> On the su...
by jbeale
Tue Apr 10, 2012 9:58 pm
Forum: Other projects
Topic: Cases for the Raspberry Pi
Replies: 866
Views: 382030

Re: Cases for the Raspberry Pi

In case it hasn't been mentioned here before, here's an impressive (painted, machined aluminum) case by Brian Garvey.


"Raspberry Slice" Deluxe case for use with the Raspberry pi mini computer board.


feature=player_embedded
by jbeale
Tue Apr 10, 2012 9:51 pm
Forum: General discussion
Topic: Video decoding specs?
Replies: 15
Views: 8636

Re: Video decoding specs?

"...Overall real world performance is something like a 300MHz Pentium 2, only with much, much swankier graphics." -http://www.raspberrypi.org/faqs
by jbeale
Fri Mar 09, 2012 5:33 pm
Forum: General discussion
Topic: Raspberry Pi Schematics
Replies: 21
Views: 9671

Re: Raspberry Pi Schematics

<t>vasquca1 said: <br/> <br/> <br/> I think it would be great if the raspberry pi organization released the schematics, bom and build instructions.<br/> <br/> <br/> My $0.02:  The schematic would be useful and interesting. The BOM/Build Instructions, I think more of academic interest than practical....
by jbeale
Fri Mar 09, 2012 5:23 pm
Forum: General discussion
Topic: Raspberry Pi Schematics
Replies: 21
Views: 9671

Re: Raspberry Pi Schematics

The I/O header is documented here:

http://elinux.org/Rpi_Low-leve.....eripherals

by jbeale
Thu Mar 08, 2012 10:30 pm
Forum: Pidora / Fedora
Topic: Fedora ARM on Raspberry Pi
Replies: 266
Views: 114510

Re: Fedora ARM on Raspberry Pi

<t>flyerblade said: <br/> <br/> <br/> Hmmm. Can you run DiskPart (from the cmd line), then "LIST DISK" OK ?<br/> <br/> <br/> I can confirm that the Windows Installer does not work as intended on WinXP SP3, because DiskPart does not see USB Flash drives (it only reports the built-in HDD).  Which is u...
by jbeale
Sat Mar 03, 2012 8:23 pm
Forum: General discussion
Topic: Microsd supported or not ?
Replies: 3
Views: 1199

Re: Microsd supported or not ?

<r>Having read about SD, miniSD and microSD at <URL url="http://en.wikipedia.org/wiki/S....._Digital">http://en.wikipedia.org/wiki/S....._Digital</URL>  I don't see how that could be true. A microSD card in an adaptor should appear electrically identical to a SD card of the same type and class; the ...

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