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by WizardOfOZ
Wed Dec 14, 2011 6:58 pm
Forum: Other projects
Topic: Software Defined Radio
Replies: 61
Views: 29152

Re: Software Defined Radio

<t>Quote from ai5eedave on December 12, 2011, 23:21<br/> (Lots of good stuff.)<br/> OK, sounds very promising. The Silicon labs synth chips have a good reputation, so should be a great starting point. You will still need some (a lot, really) of gain and selectivity between your quadrature mixer, and...
by WizardOfOZ
Mon Dec 12, 2011 10:28 pm
Forum: Other projects
Topic: Software Defined Radio
Replies: 61
Views: 29152

Re: Software Defined Radio

<t>I'm sorry if I didn't explain myself clearly in my previous post.<br/> <br/> As a rule of thumb, then VHF and UHF receivers are designed with different priorities, compared to those for shortwave. Price point has little to do with it. At VHF and higher you generally want wide tuning range, high s...
by WizardOfOZ
Sat Dec 10, 2011 12:46 am
Forum: Other projects
Topic: Software Defined Radio
Replies: 61
Views: 29152

Re: Software Defined Radio

<t>One thing to keep in mind is that many of the super integrated VHF/UHF chip radio receivers, as I assume is used in the FunCube, can suffer from very bad oscillator phase noise. If it is one thing you want below 30MHz these days, then it is low phase noise, combined with high intermodulation inte...
by WizardOfOZ
Sat Dec 03, 2011 7:23 pm
Forum: Off topic discussion
Topic: YOU SUCK: the venting thread
Replies: 948
Views: 143040

Re: YOU SUCK: the venting thread

Well, I think you should definitely count your blessings. :)

There is nothing theoretical about dead or dying electrolytic capacitors in old electronics. We haven't even mentioned Tantalum caps yet...
by WizardOfOZ
Sat Dec 03, 2011 6:43 pm
Forum: Off topic discussion
Topic: YOU SUCK: the venting thread
Replies: 948
Views: 143040

Re: YOU SUCK: the venting thread

<t>Are we still talking about equipment, which has been without power for extended periods of time (years at least, decades)?<br/> <br/> If power has been applied even intermittently, maybe once every year or two, then the caps will have had time to reform their insulation layers, and you are in tha...
by WizardOfOZ
Sat Dec 03, 2011 6:21 pm
Forum: Off topic discussion
Topic: YOU SUCK: the venting thread
Replies: 948
Views: 143040

Re: YOU SUCK: the venting thread

<t>Then all I can say is that you are either very, very lucky, or fixing the wrong things.<br/> <br/> The symptoms mentioned with the C-64 are exactly those you frequently see with bad caps. Gizmo works for a short while after applying power, then it dies a few minutes later once the bad cap(s) heat...
by WizardOfOZ
Sat Dec 03, 2011 5:49 pm
Forum: Off topic discussion
Topic: YOU SUCK: the venting thread
Replies: 948
Views: 143040

Re: YOU SUCK: the venting thread

<t>No, please don't.<br/> <br/> The hot part is probably not the problem, just a symptom.<br/> <br/> Electrolytic capacitors go bad when they have not been powered up for a few years, and generally *all* need to be replaced in old electronics before you can use the gizmo again. You need to do this *...
by WizardOfOZ
Thu Dec 01, 2011 5:09 pm
Forum: General discussion
Topic: Easy GPIO Hardware & Software
Replies: 133
Views: 47727

Re: Easy GPIO Hardware & Software

<r>Quote from jamesh on December 1, 2011, 16:04<br/> Remember that the GPIO's are unbuffered - so it will be safer to have some circuitry in their to buffer rthe device against nasty shocks.<br/> I assume there are limits to the current the SoC pins are able to sink and/or source, along with limits ...
by WizardOfOZ
Tue Nov 29, 2011 8:48 am
Forum: Other projects
Topic: Break out board (GPIO, SPI, I2C, and UART)
Replies: 189
Views: 35800

Re: Break out board (GPIO, SPI, I2C, and UART)

Then there are those, who will be happy with just using a bunch of 74HC595s and 74HC597s, and talk to them via SPI and the provided driver. Add a few resistors and MOSFETs as level shifters, bit bang the rest of the interface, and ta-daa! I/O expander. :D
by WizardOfOZ
Mon Nov 21, 2011 2:31 pm
Forum: Other projects
Topic: Break out board (GPIO, SPI, I2C, and UART)
Replies: 189
Views: 35800

Re: Break out board (GPIO, SPI, I2C, and UART)

<r>Quote from hippy on November 21, 2011, 14:13<br/> I think this is just a terminology issue. On the header connection that is often referred to collectively as "GPIO pins" there will be actual GPIO pins, 5V supply and 0V supply pins, and perhaps 3V3 and other voltage supply pins as well.<br/> Mayb...
by WizardOfOZ
Mon Nov 21, 2011 1:33 pm
Forum: Other projects
Topic: Need for an App store for RB programmers
Replies: 64
Views: 7405

Re: Need for an App store for RB programmers

The Raspberry Sauce! :D
by WizardOfOZ
Sun Nov 20, 2011 5:11 pm
Forum: Other projects
Topic: Orbiter.
Replies: 51
Views: 7240

Re: Orbiter.

<t>Quote from Burngate on November 20, 2011, 16:15<br/> WizardOfOZ is right as usual<br/> Just my point was: down here we have an atmosphere and a magnetic field protecting us. In low earth orbit we don't have the atmosphere but we do have the magnetic field. (Snippety).<br/> Actually, the linked ar...
by WizardOfOZ
Sun Nov 20, 2011 3:52 pm
Forum: Other projects
Topic: Orbiter.
Replies: 51
Views: 7240

Re: Orbiter.

<r>Quote from zebo-the-fat on November 20, 2011, 15:30<br/> If you go straight up to 200Km, you will not be in zero G, you will have almost full earth gravity, (slightly less as you will be further from the centre of the earth), you only get zero G when you are in orbit. (or did I misunderstand some...
by WizardOfOZ
Sun Nov 20, 2011 3:37 pm
Forum: Other projects
Topic: Break out board (GPIO, SPI, I2C, and UART)
Replies: 189
Views: 35800

Re: Break out board (GPIO, SPI, I2C, and UART)

<r>Quote from abishur on November 20, 2011, 15:29<br/> Max voltage for the GPIO is 3v3 which goes straight into the SoC, so I wouldn't recommend trying to send 5V down it <E>;)</E><br/> I was hoping for the +5V PSU connector being mirrored on the GPIO port, as an alternative to the Micro USB connect...
by WizardOfOZ
Sun Nov 20, 2011 1:27 pm
Forum: Other projects
Topic: Orbiter.
Replies: 51
Views: 7240

Re: Orbiter.

<t>Quote from sh4d0w0lf on November 20, 2011, 13:00<br/> That's what i was thinking<br/> Write a computer simulation for the crude case of a flight to orbit partitioned in two parts:<br/> <br/> First part is a trajectory starting at the Earth's radius, going straight up to an altitude of 200km. Igno...
by WizardOfOZ
Sun Nov 20, 2011 12:07 pm
Forum: Other projects
Topic: Orbiter.
Replies: 51
Views: 7240

Re: Orbiter.

<t>Quote from Burngate on November 20, 2011, 11:32<br/> There have been amateur satelites in orbit, notably (I believe) Surrey University.<br/> There have been about 3 dozen by now, notably the AMSAT family of amateur radio satellites. The satellite from Surrey University was OSCAR-22 (Orbiting Sate...
by WizardOfOZ
Sat Nov 19, 2011 5:56 pm
Forum: Other projects
Topic: Orbiter.
Replies: 51
Views: 7240

Re: Orbiter.

<r>You needn't concern yourself with using civilian electronics: Pi, cell phones, doesn't matter. All the usual terrestrial stuff is way too sensitive to radiation to be of any use, as was already mentioned.<br/> <br/> While the Apollo capsule computer didn't have much in the way of processing power...
by WizardOfOZ
Sat Nov 19, 2011 6:53 am
Forum: Other projects
Topic: Break out board (GPIO, SPI, I2C, and UART)
Replies: 189
Views: 35800

Re: Break out board (GPIO, SPI, I2C, and UART)

<t>Haven't seen an active reset mentioned anywhere, though that doesn't mean it isn't there.<br/> <br/> However if you need such a signal, then it is easy to build into the power supply. If you fed +5V to the Pi via, say, the GPIO port (which I believe *is* possible), then you can simply choose to u...
by WizardOfOZ
Wed Nov 16, 2011 8:54 pm
Forum: General discussion
Topic: Site and Forum issues?
Replies: 20
Views: 2769

Re: Site and Forum issues?

\"Liz smoke, don\'t breathe this!\" :D
by WizardOfOZ
Wed Nov 16, 2011 7:37 pm
Forum: Other projects
Topic: Robotics for beginners
Replies: 9
Views: 2183

Re: Robotics for beginners

<r>I suspect you may be out a bit early with your request. Most of the items you seek haven't been developed for the Pi yet, and development won't start until at least the first boards starts to ship.<br/> <br/> Judging by the chit-chat on the forum, then I would guess it won't be overly long into n...
by WizardOfOZ
Wed Nov 16, 2011 6:49 pm
Forum: General discussion
Topic: Easy GPIO Hardware & Software
Replies: 133
Views: 47727

Re: Easy GPIO Hardware & Software

<r>Quote from Burngate on November 16, 2011, 18:09<br/> So we'll need to know the physical address of the gpio?<br/> No, we need to know (at least):<br/> <br/> How many I/O pins there are.<br/> Organization/bit ordering of actual I/O pins.<br/> Which peripherals are there (I2C, SPI, etc.)<br/> Specs...
by WizardOfOZ
Wed Nov 16, 2011 4:10 pm
Forum: General discussion
Topic: Easy GPIO Hardware & Software
Replies: 133
Views: 47727

Re: Easy GPIO Hardware & Software

<t>Currently there simply isn't enough information available to start work in earnest, when it comes to the GPIO port. So please don't despair if you seem to run straight into a brick wall. The key sentence in the linked text provided by dom is this one:<br/> <br/> The exact capabilities of GPIOs va...
by WizardOfOZ
Wed Nov 16, 2011 12:42 pm
Forum: General discussion
Topic: Site and Forum issues?
Replies: 20
Views: 2769

Re: Site and Forum issues?

No argument there. The editors do tend to go fishing for comments through OT posts more often than not.
by WizardOfOZ
Wed Nov 16, 2011 8:49 am
Forum: General discussion
Topic: Site and Forum issues?
Replies: 20
Views: 2769

Re: Site and Forum issues?

<r>[quote]<B><s>[b]</s>Quote from Jongoleur on November 16, 2011, 08:41<e>[/b]</e></B><br/> Its a mixture of time of day and /.[/quote]<br/> To clarify, then a popular tech site, slashdot.org, <URL url="http://tech.slashdot.org/story/11/11/15/214207/raspberry-pi-pcb-layout-revealed"><s>[url=http://t...
by WizardOfOZ
Tue Nov 15, 2011 7:48 pm
Forum: Other projects
Topic: Need for an App store for RB programmers
Replies: 64
Views: 7405

Re: Need for an App store for RB programmers

<r>@Bacan,<br/> <br/> All *BSD licensed code should be useful as a basis, if you intend to develop a commercial product without having to release the source code. There are probably many other suitable licenses for that purpose, but those stand out for me.<br/> <br/> If you don't mind releasing the ...

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