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by Ravenous
Fri Feb 06, 2015 4:34 pm
Forum: Off topic discussion
Topic: Somebody needs a Raspberry PI...
Replies: 13
Views: 1626

Re: Somebody needs a Raspberry PI...

The Druids brought us Stonehenge though. Spinal Tap's best tune. So not all bad...
by Ravenous
Fri Feb 06, 2015 4:23 pm
Forum: Off topic discussion
Topic: Fresnel Lenses
Replies: 23
Views: 3848

Re: Fresnel Lenses

In that case I think your arrangement is right, except I don't think you need a second condenser: LED -> a distance equal to fresnel lens focal length -> fresnel lens -> LCD panel -> Triplet lens Problem 1 - I'm not sure a reflector behind the LED is needed, if it's radiating everything forwards Pro...
by Ravenous
Fri Feb 06, 2015 1:55 pm
Forum: General discussion
Topic: Raspberry Pi 2 Model B CPU not centered. Should I worry?
Replies: 12
Views: 2308

Re: Raspberry Pi 2 Model B CPU not centered. Should I worry?

marked wrote:
DougieLawson wrote:The last stage on the TV line was the girl with the rubber mallet who hit the TV three times before it got boxed for shipping.
Pre-applied Percussive Prolongation?
Pre-emptive prang prevention?
by Ravenous
Fri Feb 06, 2015 11:15 am
Forum: Off topic discussion
Topic: 3D Printing
Replies: 56
Views: 7085

Re: 3D Printing

That link looks like a pretty savage piece of crookedness, but... Sometimes people apply for and get obvious patents, not to prevent others using the same idea, but simply to prevent anyone sueing them for putting it into production. I'm not a patent lawyer, but apparently this is a standard practic...
by Ravenous
Fri Feb 06, 2015 11:05 am
Forum: Off topic discussion
Topic: Fresnel Lenses
Replies: 23
Views: 3848

Re: Fresnel Lenses

Good point about the screen, etc. To clarify, my comment above was about the condenser (to concentrate the light source) and not the actual projector (which would require a proper projection lens, or at least something adapted from something else.) I was talking about something like an overhead proj...
by Ravenous
Fri Feb 06, 2015 9:15 am
Forum: Off topic discussion
Topic: Fresnel Lenses
Replies: 23
Views: 3848

Re: Fresnel Lenses

So, if this is all correct, then I'd want a Fresnel lens with a focus length of 200mm, right? I think that's correct. (My optics is very rusty, if lenses can get rusty!) I forgot all the lens equations, but I think 200mm length means a magnifying glass of around 2x-3x. So if you can find a fresnel ...
by Ravenous
Fri Feb 06, 2015 8:53 am
Forum: Bare metal, Assembly language
Topic: BCM 2836 and the RPi 2 ?
Replies: 95
Views: 29881

Re: BCM 2836 and the RPi 2 ?

If you take your numbers of boards and examine just how many are actually being used for the supposedly target audience you will find the product is a failure. Do you have a source for that? Just curious how many are being used by kids and how many by adult hobbyists (and industrial applications ma...
by Ravenous
Thu Feb 05, 2015 5:45 pm
Forum: Beginners
Topic: Gradiometer for archaeology
Replies: 21
Views: 4878

Re: Gradiometer for archaeology

Yes I suspected it was something like that. The question is, can they tell you how to get the data out? It just seems odd that the data for this part is so vague... there's no way you could actually build a device from the circuit they give... Alternatively you could use any D-A converter with the t...
by Ravenous
Thu Feb 05, 2015 5:38 pm
Forum: Off topic discussion
Topic: Somebody needs a Raspberry PI...
Replies: 13
Views: 1626

Re: Somebody needs a Raspberry PI...

Oh, "our" guy's already got email and stuff, I'm sure. He used to be an executive for one of the oil companies, believe it or not! (Justin Welby)
by Ravenous
Thu Feb 05, 2015 5:07 pm
Forum: Other programming languages
Topic: artificial intelligence
Replies: 4
Views: 1840

Re: artificial intelligence

Years ago I did some very basic course work on fuzzy logic, and on neural networks. (All paper based so sorry, no references. It was all basic college level maths though.) Interesting stuff, though at the basic level we did they were just pattern recognition systems really. I'm a bit afraid that peo...
by Ravenous
Thu Feb 05, 2015 4:34 pm
Forum: Off topic discussion
Topic: Somebody needs a Raspberry PI...
Replies: 13
Views: 1626

Re: Somebody needs a Raspberry PI...

Heh, he sounds a bit like me! (The dinosaur bit.)

Shall we all nag Liz to send him a raspi? I'd love to see him try to get kernel changes past Linus. (No, really.)
by Ravenous
Thu Feb 05, 2015 3:57 pm
Forum: Beginners
Topic: Lightweight Antivirus for Pi? To catch Windows viruses.
Replies: 25
Views: 12046

Re: Lightweight Antivirus for Pi?

I've heard people mention avast, ClamAV, and stuff like that. Never tried 'em though.

Worthwhile if you have a server or Windows-style files on the system, as you say.

Hopefully you will get some more useful responses, but not from some of the people on thsi forum....
by Ravenous
Thu Feb 05, 2015 3:38 pm
Forum: Beginners
Topic: Newbie MIDI and OSC
Replies: 1
Views: 548

Re: Newbie MIDI and OSC

Have you done a search yet? Quite a few people have used PureData already, for various things. (Admittedly, if they say just "pd" then the search probably won't work!)

I haven't seen anyone doing the OSC/ethernet bit, so you might need to do something new there.
by Ravenous
Thu Feb 05, 2015 1:32 pm
Forum: Beginners
Topic: Square Inch Electronics
Replies: 5
Views: 765

Re: Square Inch Electronics

Now I have 2 dozen spare 1" square boards with 9 holes in each direction. So it's possible to connect to a maximum of 9 (or 18) adjacent GPIO header pins. These are small squares with lots of pads in a square grid? If so, perhaps you could put conductive rubber or plastic above one and make it into...
by Ravenous
Thu Feb 05, 2015 1:27 pm
Forum: Astro Pi
Topic: Can it use windows?
Replies: 6
Views: 2721

Re: Can it use windows?

Yup, nice view. Anyone have a problem with heights? :lol:
Image
Image
by Ravenous
Thu Feb 05, 2015 11:22 am
Forum: General discussion
Topic: pi 2 what software changes to get fsf approval?
Replies: 25
Views: 3800

Re: pi 2 what software changes to get fsf approval?

So, what I meant was that, generally speaking, Richard Stallman did help the OpenSource movement a lot in a practical sense Correct. If I remember correctly, the GNU project had a lot of Unix compatible, but free, bits of software available for many years. Linus T "just" wrote the first version of ...
by Ravenous
Thu Feb 05, 2015 10:08 am
Forum: Off topic discussion
Topic: Salvaging Old Components
Replies: 4
Views: 757

Re: Salvaging Old Components

I expect they would be useful for driving LEDs, at a higher current than the Raspi's GPIO outputs can safely manage. The 74HC device might work directly off the 3.3V outputs of the raspi - dunno but the voltage thresholds might be high enough - the datasheet seems to imply this (see the Recommended ...
by Ravenous
Thu Feb 05, 2015 9:56 am
Forum: General discussion
Topic: pi 2 what software changes to get fsf approval?
Replies: 25
Views: 3800

Re: pi 2 what software changes to get fsf approval?

I'd just like to add the FSF are not mad; they do have a list of hardware which does exist that they consider free. (I think I saw the Cubie on it, but I'll leave people who care to check this. I have looked at the FSF site several times over the years and sympathise with some of their aims.)
by Ravenous
Thu Feb 05, 2015 9:48 am
Forum: General discussion
Topic: pi 2 what software changes to get fsf approval?
Replies: 25
Views: 3800

Re: pi 2 what software changes to get fsf approval?

It certainly flies in the face of a statement from The Raspberry Pi Foundation this week that said "We want the Pi to become more open as time goes by" (not exact words). Was that from Eben himself? I forget. JamesH did state he was giving a personal opinion. Right before the bit you quoted. Is it ...
by Ravenous
Thu Feb 05, 2015 9:31 am
Forum: Astro Pi
Topic: Can it use windows?
Replies: 6
Views: 2721

Re: Can it use windows?

I should think so - there are plenty of photos taken with regular cameras, though I don't know if they ever clamp cameras in place, for long duration photography, or just use handheld: http://petapixel.com/2013/06/10/photographing-earth-from-the-cupola-on-the-international-space-station/ A room with...
by Ravenous
Thu Feb 05, 2015 9:20 am
Forum: Beginners
Topic: Battery powered Pi
Replies: 3
Views: 518

Re: Battery powered Pi

Yeah that will definitely work, I suppose you just need the right sort of USB to mini USB lead. Should run for an hour or two at least...

Do you really have loads of those, and if so are they surplus junk? :lol:
by Ravenous
Thu Feb 05, 2015 9:09 am
Forum: General discussion
Topic: pi 2 what software changes to get fsf approval?
Replies: 25
Views: 3800

Re: pi 2 what software changes to get fsf approval?

Is there a listing that lists pi 2 software that must find a free software solution in order to get a fsf hardware approval? Just for interest, if the OP's stil following this: https://www.fsf.org/campaigns/priority-projects/reverse-engineering Raspberry Pi's mentioned on that page; I believe that'...
by Ravenous
Wed Feb 04, 2015 5:43 pm
Forum: Off topic discussion
Topic: DRAM + NAND Chip
Replies: 4
Views: 1134

Re: DRAM + NAND Chip

As far as I'm aware there's no way you could fit something like that on a raspi. (Unless one of the engineers knows better.)
by Ravenous
Wed Feb 04, 2015 4:25 pm
Forum: Beginners
Topic: SNAPPY UBUNTU CORE kernel panic
Replies: 6
Views: 3966

Re: SNAPPY UBUNTU CORE kernel panic

To bootstrap the brave new snappy Ubuntu for Devices world we have extended support of Snappy Ubuntu Core beyond the cloud by introducing a support for bare metal ARMv7-A powered platforms. That may be true, but I'm pretty sure that will not run on the raspi Model B+. The B+ is not an ARM-v7, and U...
by Ravenous
Wed Feb 04, 2015 4:02 pm
Forum: Beginners
Topic: Gradiometer for archaeology
Replies: 21
Views: 4878

Re: Gradiometer for archaeology

The datasheet seems to indicate its outputs (D0-D7) can go straight to a microprocessor. So I would guess dropping them down (by a potential divider, for each pin) to 3.3V and connecting to the raspi's GPIO pins will work? But, the datasheet doesn't say how to do this... I would ask them directly fo...

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