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by johnbeetem
Wed Jun 26, 2013 11:10 pm
Forum: Off topic discussion
Topic: who knew bagpipes could be cool
Replies: 6
Views: 1525

Re: who knew bagpipes could be cool

According to the late Irish comedian Dave Allen, bagpipes were invented by the Irish. They gave them to the Scots, who still haven't caught on to the joke. All kidding aside, I rather like the pipes. Although I heard a cautionary story of a man who died of laughter while watching a British comedy sh...
by johnbeetem
Mon Jun 24, 2013 11:26 pm
Forum: General discussion
Topic: Which SOC? Datasheets? Schematics? GPIOs? Open Drivers?
Replies: 9
Views: 1841

Re: Which SOC? Datasheets? Schematics? GPIOs? Open Drivers?

wskinny wrote:Well, I do need the schematics, preferably editable in either DipTrace or design spark, as I'm considering a derivative design with dual and improved SoC's and an additional MCU.
The RasPi schematics in .pdf form are at the RasPi Hardware Wiki: http://elinux.org/Rpi_Hardware#Schematic_.2F_Layout
by johnbeetem
Sat Jun 22, 2013 6:07 pm
Forum: General discussion
Topic: Circuit burnout issue
Replies: 11
Views: 3372

Re: Circuit burnout issue

Since D17 desoldered itself, it's most likely that it was conducting a large current from a power supply greater than 5V, as others have suggested upstream. Putting an electronic device directly on a carpet is a bad idea. 1. You could easily have a bit of conductive material in the carpet, which cou...
by johnbeetem
Tue Jun 18, 2013 6:53 pm
Forum: Off topic discussion
Topic: music suggestiongs for a raspberry pi montage
Replies: 7
Views: 1340

Re: music suggestiongs for a raspberry pi montage

Well, the only song I can think of off-hand that features "raspberries" is a WWII-era comic song recorded by Spike Jones, but mentioning the title will trigger Godwin's Law. Also, I don't think it's at all appropriate for your application. So, I'll suggest the song that's most associated with comput...
by johnbeetem
Mon Jun 17, 2013 6:35 pm
Forum: General discussion
Topic: Why were so many pins dedicated to power & gnd
Replies: 18
Views: 4123

Re: Why were so many pins dedicated to power & gnd

huh? I can get one at an affordable $10000USD? And THEN I have to buy $1000USD probes? That's the price a sub-compact car! $35USD for a RPi, $10000USD for a scope! :o How about a scope for under $200USDs? What about an old vacuum tube scope? That I do have. It's "affordable" for a reasonable-size c...
by johnbeetem
Mon Jun 17, 2013 6:24 pm
Forum: General discussion
Topic: I made a Raspberry PI Laptop
Replies: 840
Views: 377088

Re: I made a Raspberry PI Laptop

I haven't traced the power paths, but I'm guessing that the polyfuse on the Pi's USB power line may be the problem and I'll try shorting the polyfuse to see if that has any effect. I was actually surprised that the Pi remained powered up and running fine while I was swapping cables around and only ...
by johnbeetem
Sun Jun 16, 2013 1:36 pm
Forum: General discussion
Topic: Why were so many pins dedicated to power & gnd
Replies: 18
Views: 4123

Re: Why were so many pins dedicated to power & gnd

I take it you would need an oscilloscope to see this. Definitely need a 'scope to see ground noise problems. In many cases, you need a very fast 'scope (1G sample/sec or faster) and active probes. Passive 'scope probes can filter out subtle signals so you can't see them, and in some cases filter th...
by johnbeetem
Sun Jun 16, 2013 3:56 am
Forum: General discussion
Topic: Why were so many pins dedicated to power & gnd
Replies: 18
Views: 4123

Re: Why were so many pins dedicated to power & gnd

I take it you would need an oscilloscope to see this. Definitely need a 'scope to see ground noise problems. In many cases, you need a very fast 'scope (1G sample/sec or faster) and active probes. Passive 'scope probes can filter out subtle signals so you can't see them, and in some cases filter th...
by johnbeetem
Sat Jun 15, 2013 7:51 pm
Forum: General discussion
Topic: Why were so many pins dedicated to power & gnd
Replies: 18
Views: 4123

Re: Why were so many pins dedicated to power & gnd

according to a search, I forgot which, its in the MHz range if written in c. I just wrote a script to oscillate four 7-segment LEDs. From looking at it I can guess its in the KHz range. You know what I mean? Persistence of vision and such? You just swing your eyes across and you see the individual ...
by johnbeetem
Fri Jun 14, 2013 6:44 pm
Forum: Off topic discussion
Topic: Software Market- Paying peanuts for programs
Replies: 11
Views: 2223

Re: Software Market- Paying peanuts for programs

Maybe one of the reasons why kids like me do not get into coding is that there does not seem to be any attractive profits involved. IMO if you want to make lots of money, I suggest going into something financial. The best programmers do it because the love the challenge and the thrill of seeing som...
by johnbeetem
Fri Jun 14, 2013 6:33 pm
Forum: General discussion
Topic: Why were so many pins dedicated to power & gnd
Replies: 18
Views: 4123

Re: Why were so many pins dedicated to power & gnd

If the GPIO signals were all very slow, you'd only need one ground. However, whenever you have signals that change fast -- which is typically all digital IC pins nowadays -- those sharp edges require having very good ground connections or the edges will cause noise on other signals. A good rule of t...
by johnbeetem
Thu Jun 13, 2013 7:33 pm
Forum: General discussion
Topic: Rasberry pi's c6 capacitor has been getting unusually warm.
Replies: 16
Views: 2463

Re: Rasberry pi's c6 capacitor has been getting unusually wa

Seems like RG2, D17, and C6 are all warm. I have one of the newer raspberry pi's made in China, so I'm not surprised if the board is faulty. :x Also I've heard that RG2 gives 1/3 of its energy off as heat, so the other components may just be hot do to the radiating warmth. Does every pi get at leas...
by johnbeetem
Wed Jun 05, 2013 4:24 am
Forum: General discussion
Topic: problems setting raspberry pi up with lapdock 500
Replies: 107
Views: 31400

Re: problems setting raspberry pi up with lapdock 500

Hey man thanks for the response. Yeah I made sure the lapdock was charged and I also tried it while charging, it still wouldn't turn on. I saw the link you sent me but doing that stuff is a bit past my skill level heh, so is there simple another cable I can get that will definitely have the DDC/CEC...
by johnbeetem
Sun Jun 02, 2013 4:44 am
Forum: General discussion
Topic: problems setting raspberry pi up with lapdock 500
Replies: 107
Views: 31400

Re: problems setting raspberry pi up with lapdock 500

There's been a lot posted here and elsewhere about the Motorola Atrix Lapdock. I expect the Lapdock 500 behaves similarly. A good starting point is the Atrix Lapdock section at the RasPi Hardware Wiki: http://elinux.org/RPi_Screens#Motorola_Atrix_Lapdock It summarizes the most important Lapdock lore...
by johnbeetem
Mon May 27, 2013 11:24 pm
Forum: General discussion
Topic: New version of Pi. When?
Replies: 94
Views: 18558

Re: New version of Pi. When?

In order to hold the sort of price point the Pi is at, let alone actually holding the the Pis price, "trickling out" won't do it. You have to get to the point that the design costs have been amortized, yields are excellent, and the chips are very cheap to make. In short, you have to wait until the ...
by johnbeetem
Sun May 26, 2013 2:07 am
Forum: General discussion
Topic: Newbie electriconics question..
Replies: 24
Views: 2590

Re: Newbie electriconics question..

My question is, will my multimeter always show +5V, regardless of what value R is? Yes, because you measure always between +5V and GND. Thanks, I will check up in the links you provided. In that case, is it even necessary for me to even have a resistor placed there, or can I simply leave it out and...
by johnbeetem
Fri May 24, 2013 9:28 pm
Forum: General discussion
Topic: Maker Fairey Tales - NOOBS and Pidora and Wayland, Oh My!
Replies: 53
Views: 15678

Re: Maker Fairey Tales - NOOBS and Pidora and Wayland, Oh My

The envelope, please ... and the award for the ability to use Google to actually travel back in time goes to ... John Beetem! Beetem? Why I hardly even know him! Yes, Bunky, things haven't just gone from bad to worse, they've entered Dante's Inferno, where there is a ring reserved just for rabid Pi...
by johnbeetem
Fri May 24, 2013 7:26 pm
Forum: Off topic discussion
Topic: Great Debate of the Age
Replies: 32
Views: 3087

Re: Great Debate of the Age

Q: Why are prunes wrinkled?
A: Ever tried to iron one?

From my Henny Youngman record:
A guy has bandages over both ears. His friend asks him: "What happened to you?" He says: "I was ironing and the phone rang." "So what happened to your other ear?" "I had to call the doctor."
by johnbeetem
Wed May 22, 2013 1:44 pm
Forum: General discussion
Topic: Maker Fairey Tales - NOOBS and Pidora and Wayland, Oh My!
Replies: 53
Views: 15678

Re: Maker Fairey Tales - NOOBS and Pidora and Wayland, Oh My

So, what was your problem, Bunky? I too have no idea who Bunky is or what it is in refernce to. Amazing -- for some reason there's no reference to it on Wikipedia. There's an old [USA and maybe elsewhere] comedy routine entitled "What's the matter, Bunky?" where an old codger is trying to console h...
by johnbeetem
Mon May 20, 2013 9:26 pm
Forum: General discussion
Topic: News articles and blog posts about Raspberry Pi
Replies: 1021
Views: 191565

Re: News articles and blog posts about Raspberry Pi

Yesterday's New York Times (Sunday 19 April) has an article called "There’s a Method to My Desk’s Madness", featuring Ladyada's desk. A Raspberry Pi is easily found amidst the "creative clutter" :)

http://www.nytimes.com/interactive/2013 ... .html?_r=0
by johnbeetem
Sun May 19, 2013 1:54 am
Forum: General discussion
Topic: Trigger action from external LED?
Replies: 2
Views: 471

Re: Trigger action from external LED?

I'd definitely go with an opto-isolator. You can read more about them at Wikipedia: http://en.wikipedia.org/wiki/Opto-isolator. Opto-isolators generally use infra-red LEDs so the voltage drop is less than a visible LED. That means that if you put it in parallel with the visible LED most of the curre...
by johnbeetem
Fri May 17, 2013 6:01 pm
Forum: Python
Topic: Help with N Queens
Replies: 3
Views: 772

Re: Help with N Queens

I've done it using a permutation method. All solutions have exactly one queen in each row, in a different column. So you simply start with N rows, each with a queen in a different column, and then enumerate all the row permutations using recursion. For each permutation, just check for diagonal captu...
by johnbeetem
Fri May 17, 2013 1:03 am
Forum: Off topic discussion
Topic: How useful is pseudocode?
Replies: 18
Views: 4794

Re: How useful is pseudocode?

Array indexes should be array(x,y) to match mathematical usage and every other usage on Earth except C and its derivatives. I would accept square brackets to avoid confusion with parentheses. Do not use [y][x] unless you are intending to teach Iliffe Vectors, and you are not. ... LEN is a pointless...
by johnbeetem
Thu May 16, 2013 5:31 pm
Forum: Off topic discussion
Topic: How useful is pseudocode?
Replies: 18
Views: 4794

Re: How useful is pseudocode?

Pseudo-code has its uses. It's a great way to describe an algorithm in a language-independent way, so that others can implement it in whatever they like. Pseudo-code removes the distraction of ugly syntax and lets you combine whatever features you like from various languages or your own imagination....
by johnbeetem
Wed May 08, 2013 11:31 pm
Forum: Off topic discussion
Topic: Raspberry Pi Vs. Alternatives
Replies: 62
Views: 41427

Re: Raspberry Pi Vs. Alternatives

You might check out the new BeagleBone Black. If you want to talk to a small screen, BBone has a lot of options. Some links:

http://beagleboard.org/
http://www.raspberrypi.org/phpBB3/viewtopic.php?t=41489
http://www.element14.com/community/thread/23575

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