The Raspberry Pi

[burninbush]

I hope someone here can help me with my RaspberryPi problem ... i.e., configuring a usb wifi dongle.

 

This is an old part, has a ZD1211 chipset inside, known to work on win2k and some linux distros that I have tried it with a few years back. The Pi knows it's there, an #lsmod shows 5 -6 related items added when I plug it in.

 

BUT .. the only config util that I can see is wpa_supplicant, and it completely refuses to 1) admit the dongle exists, and 2) won't let me declare that my home wifi uses a WEP key. That last might be related to the first problem.

 

Any help? Basically I need to know how to get it to request an IP address. I have fooled with iwconfig wlan0 a bit, no success so far.

[ross549]

It could be the chip is drawing too much power from the power supply, and cannot operate properly. What kind of USB power supply are you using? TP1 and TP2 on the board need to be at 4.875VDC or higher (measured with a voltmeter) in order for everything to function properly, or you will have strange issues.

 

Adam

 

http://elinux.org/RPi_VerifiedPeripherals#USB_Wi-Fi_Adapters

[abarbarian]

http://www.slblabs.com/2012/09/27/rpi-wifi/

 

This section is dongle dependent. I had an old Digicom USBWAVE54 Dongle, which is based on a Zydas ZD1211 chipset, so here’s how I proceeded to install the correct drivers for my dongle:

 

 

Holger Leusch, Benjamin Reichel and Karina Hochstein have found themselves with a similar problem. Worse still, Holger travels to Cambodia a lot, and his German phone provider doesn’t even have a roaming agreement with any of the Cambodian telcos, so he’s not able to use his phone there at all. He found VoIP unusable in Cambodia, with patchy calls, lousy bandwidth, delays and dropouts. Like us, he needed to be in constant touch with his office.

Enter (you knew this was coming, didn’t you?) the Pi.

 

http://www.raspberrypi.org/archives/3679

 

Neato

[burninbush]

It could be the chip is drawing too much power from the power supply, and cannot operate properly. What kind of USB power supply are you using? TP1 and TP2 on the board need to be at 4.875VDC or higher (measured with a voltmeter) in order for everything to function properly, or you will have strange issues.

 

Adam

 

http://elinux.org/RP..._Wi-Fi_Adapters

 

 

Thanks for the reply and link. I have ordered a dongle that is known to work with the Pi.

 

I found the problem [?] in dmesg; unable to load the firmware that mine requires. Updated everything related to wifi and the zydas 1211, without success.

 

I have two of these old zydas 1211 dongles; today I verified that they work perfectly on Porteus2 and mint14, so rather than struggle further with the Pi I'm buying a new adapter [off the list] that is said to work straight out of the blister pack.

 

My power supply is a wall wart type that I found in my bag of hardware leftovers -- 5v regulated at 1.2amps. So far it has not blinked, actually measures 5.1volts. While I'm waiting for the dongle I'll try to decide on some sort of box to put it into.

[abarbarian]

Burninbush was my info of no use ? It shows how to use a Zydas ZD1211 chipset powered dongle with the Pi.

[burninbush]

Burninbush was my info of no use ? It shows how to use a Zydas ZD1211 chipset powered dongle with the Pi.

 

 

Hi, and thank you again for the link which was definitely useful. I used apt-get update, and then got the latest firmware for the zd1211, but it still refused to load onto my dongles, failed at the first dmesg step repeatedly. It clearly worked on his dongle, but won't on mine. But I did learn what files and commands to use. I anticipate that the one I ordered will come up automatically.

[burninbush]

Well, the tiny usb dongle arrived today, and it [with some work] solved the problem. What the company shipped is not the Airlink part they advertised, rather it's unmarked as to brand. Inside it has a Ralink rt2800 chipset. After some net searching I found a post from someone who had gotten a rt2800 dongle to work on his Pi after editing a /etc/networks file to add his WEP setup; I did the same here and on reboot it went to the router for an IP address, working. The Pi already had current firmware for this dongle [as it also had for the zydas dongle]. Wpa_supplicant on the Pi also refuses to admit that the new dongle is present -- not sure what's going on with that app.

 

After getting it to work I had to go back and retry the zydas dongle, but it still doesn't work. Too old, maybe, for the current firmware?

 

Good news: the new dongle is approximately 2x as fast as the zydas when I run it on one of my 3ghz AMD desktops; speedtest.net has it downloading at a sizzling 20megabits /second -- while the wired link on the same box tops out at 27 megabits/second -- I call that a good dongle. Not sure yet how it'll work over a distance -- hard to see how they could put much of an antenna in that tiny package.

[abarbarian]

WEP ??? Thats not very secure.

Have you joined the Rasp forums and asked for help over there ??

 

http://www.raspberrypi.org/phpBB3/posting.php?mode=reply&f=30&t=9875

 

[lewmur]

WEP ??? Thats not very secure.

 

If that's all the router he's trying to connect to handles, then that's what he has to use. But, personally, I think the WEP vs WPA security is irrelevant. Anyone capable of breaking WEP is also capable of breaking WPA. Just takes a little longer. If you are really concerned about security on a WLAN, then the type of encryption you use should be way down on the list of things you need to worry about.

 

Sure, if you have WPA, then use it. But I wouldn't rush out and spend money on a new router and dongle just to get WPA for a home network.

Edited April 18, 2013 by lewmur

[Guest LilBambi]

WPA2 PSK AES is still safer than WEP by a long shot. Particularly in a city or large town environment. Maybe if you live in the boonies, it's not as necessary because there are not has many trying to hit the router, but even there I always recommend WPA2 AES.

 

But go as high as one can based on the lowest common denominator in computer hardware. Get the hardware up as high as it can go. Then consider replacing older hardware if possible. If not do the best you can.

 

How To Crack WPA / WPA2 - SmallNetBuilder

 

WPA hashes the key using the wireless access point's SSID as a salt. The benefits of this are two-fold.

 

First, this prevents the statistical key grabbing techniques that broke WEP by transmitting the key as a hash (cyphertext). It also makes hash precomputation via a technique similar to Rainbow Tables more difficult because the SSID is used as a salt for the hash. WPA-PSK even imposes a eight character minimum on PSK passphrases, making bruteforce attacks less feasible.

 

Doesn't mean it can't happen. It has happened at least partially if the hacker/cracker has enough time. In a brute force attack on 256 AES...

 

Theoretical limits

 

The resources required for a brute-force attack grow exponentially with increasing key size, not linearly. Although US export regulations historically restricted key lengths to 56-bit symmetric keys (e.g. Data Encryption Standard), these restrictions are no longer in place, so modern symmetric algorithms typically use computationally stronger 128- to 256-bit keys.

 

There is a physical argument that a 128-bit symmetric key is computationally secure against brute-force attack. The so-calledLandauer limit implied by the laws of physics sets a lower limit on the energy required to perform a computation of kT · ln 2 per bit erased in a computation, where T is the temperature of the computing device in kelvins, k is the Boltzmann constant, and the natural logarithm of 2 is about 0.693. No irreversible computing device can use less energy than this, even in principle.[2] Thus, in order to simply flip through the possible values for a 128-bit symmetric key (ignoring doing the actual computing to check it) would theoretically require 2128 − 1 bit flips on a conventional processor. If it is assumed that the calculation occurs near room temperature (~300 K) the Von Neumann-Landauer Limit can be applied to estimate the energy required as ~1018 joules, which is equivalent to consuming 30 gigawatts of power for one year. This is equal to 30×109 W×365×24×3600 s = 9.46×1017 J or 262.7 TWh (more than 1/100th of the world energy production).[citation needed] The full actual computation—checking each key to see if you have found a solution—would consume many times this amount.

 

However, this argument assumes that the register values are changed using conventional set and clear operations which inevitably generate entropy. It has been shown that computational hardware can be designed not to encounter this theoretical obstruction (seereversible computing), though no such computers are known to have been constructed.[citation needed]

 

As commercial available successors of governmental ASICs Solution also known ascustom hardware attack, today two emerging technologies have proven their capability in the brute-force attack of certain ciphers. One is modern graphics processing unit (GPU) technology,[3][page needed] the other is the field-programmable gate array (FPGA) technology. GPUs benefit from their wide availability and price-performance benefit, FPGAs from their energy efficiency per cryptographic operation. Both technologies try to transport the benefits of parallel processing to brute-force attacks. In case of GPUs some hundreds, in the case of FPGA some thousand processing units making them much better suited to cracking passwords than conventional processors. Various publications in the fields of cryptographic analysis have proved the energy efficiency of today’s FPGA technology, for example, the COPACOBANA FPGA Cluster computer consumes the same energy as a single PC (600 W), but performs like 2,500 PCs for certain algorithms. A number of firms provide hardware-based FPGA cryptographic analysis solutions from a single FPGA PCI Express card up to dedicated FPGA computers.[citation needed] WPA and WPA2 encryption have successfully been brute-force attacked by reducing the workload by a factor of 50 in comparison to conventional CPUs[4][5] and some hundred in case of FPGAs.

 

AES permits the use of 256-bit keys. Breaking a symmetric 256-bit key by brute force requires 2128 times more computational power than a 128-bit key. A device that could check a billion billion (1018) AES keys per second (if such a device could ever be made - as of 2012, supercomputers have computing capacities of 20 Peta-FLOPS, see Titan. So 50 supercomputers would be required to process (1018) operations per second) would in theory require about 3×1051 years to exhaust the 256-bit key space.

 

An underlying assumption of a brute-force attack is that the complete keyspace was used to generate keys, something that relies on an effective random number generator, and that there are no defects in the algorithm or its implementation. For example, a number of systems that were originally thought to be impossible to crack by brute force have nevertheless been cracked because the key space to search through was found to be much smaller than originally thought, because of a lack of entropy in their pseudorandom number generators. These include Netscape's implementation of SSL (famously cracked by Ian Goldberg and David Wagner in 1995[6]) and a Debian/Ubuntu edition of OpenSSL discovered in 2008 to be flawed.[7] A similar lack of implemented entropy lead to the breaking of Enigma's code.[8][9]

Edited April 19, 2013 by LilBambi

[ross549]

Not to mention that WPA is very different than WPA 2.

 

Adam

[therock247uk]

/me hates wifi hackers!!

[lewmur]

/me hates wifi hackers!!

Actually, wifi hacking of home wlans isn't really a big security issue anymore. I dare say 99% of people who get hacked via wifi have it occur in public places. There was a time when hackers would cruise around in their cars looking for wlans to crack. But the tremendous proliferations of wlans makes that pretty much a thing of the past. But having someone try to hack your laptop or tablet while you're having coffee connected to a pubic wifi spot, is much more likely.

 

So, if you've learned to lock down your computer for use in public wifi spots, where the wlan is, by definition, open to everybody, then you should be safe at home no matter what encryption you use. Locking down your device, by using Linux, is far far more important that choosing WPA2 encryption over WEP. Like I said, the only difference between the two is just a matter of how long it takes to crack one over the other. Just google "cracking WPA2" and you'll find plenty of articles with step by step instructions on how to do it.

[ross549]

I knew WEP and WPA were crackable. I thought WPA2 was not cracked outside a dictionary attack (brute force). My understanding was with a sufficiently long and random key would be extremely secure.

 

Adam

[Guest LilBambi]

Yep, covered in my posting above.

[abarbarian]

Good info in your clip Fran. I just set up broadband for me mum with TalkTalk and her wireless router from them comes with WPA2. I managed to hammer out the same deal for her that I have and she is as happy as Larry phoning all her chums abroad for free. In all the three conversations I earwigged on her chums showed some concern at the cost of the lengthy call, me mum casually told them that she had negotiated a deal with a new telephone supplier and that all her calls were free.She sounded really happy, don't know if it was the no cost call or the feather in her cap for having such a deal.

[Guest LilBambi]

Good one abarbarian!

[abarbarian]

We pit six Raspberry Pi operating systems against one another to find out which one is the king of the tiny computer distros

 

 

http://www.linuxuser.co.uk/reviews/distro-super-test-pi-edition/comment-page-1#comment-293642

 

I just had to post a comment and straighten him out about his dodgy Arch knowledge.

[abarbarian]

Lol! Good for you, abarbarian!

 

This month's Linux J our all is all about the pi! including clustering. The opening pages is the results of a survey on how do you use it? So many things from dvr to sound system to web hosting!

 

Ps

I am not correcting this iPad's auto correct. It's too much of a fight...

 

Got a linky ?

 

I have this on my bar thingy in FF,

 

http://www.raspberrypi.org/

 

The latest article is a hoot,

 

Kegerface is a digital tap list display from SchrodingersDrunk,

 

Alley Cat Chocolate Espresso Stout I want.

 

Yeah if he is going to write about Arch he had better get his facts straight.

[abarbarian]

For all you photographers,

 

 

 

 

Gigapi: a Raspberry Pi rig for gigapixel photography

 

 

 

But if you’re not in charge of a defence silo, you can still take your own gigapixel images by stitching together many megapixel-sized images from an SLR camera on a motorised mount into a giant, seamless mosaic with very fine detail. You’ll need something approaching a defence budget if you’re going to do this yourself without building your own hardware, though; I spent a few seconds googling and found that off-the-shelf motorised rigs for your camera can cost nearly $1000.

Tim and Jack Stocker thought this was daft, so they built their own out of MDF, some Lego turntables, and a Pi with a cheap stepper motor attached.

 

Here is the site if you want to make your own

 

http://gigapi.blogspot.co.uk/

 

Some fine examples of Gigapixel pictures

 

http://gigapan.com/gigapans/?order=most_popular&page=1&query=sophiewilson

 

[rolanaj]

I finally got online with my raspberry pi. I was waiting for all the extras I ordered to go with it. New red acrylic case from these guys, a roll up keyboard and a super cheap mouse from Amazon as well as a Patriot 32gb SDHC card. I had a D-Link Wireless N USB Adapter (DWA-130) kicking around and a no name usb hub. The wireless worked like a charm. The roll up keyboard is a bit annoying and I suspect I really need to get a better usb hub with its own power source as it seemed to run a bit slow. I installed Raspbian Wheezy on the SD card. Now I have to figure out what I want to do with it, so many ideas to choose from.

[abarbarian]

You will soon find some use for the Pi. Keep an eye on this site and you will spot a funky idea to suit sooner or later.

 

http://www.raspberrypi.org/

 

The roll up looks an amazing idea but seems to not be so good in real life from the reviews I read at Amazon. I have been looking at getting a wireless mini kb with trackpad for a while now but keep on getting put of by buyers reviews.

 

You will need a powered hub if you are running more than a kb and mouse.

 

At the moment I am just using my Pi to surf the web and play video clips and pics when I am at me mums. With a bit of tinkering thrown in aswell. I do have some projects in mind but I need to find some spare time to play.

 

Have fun with the pie making.

[ross549]

What kind of USB power supply are you using? If your keyboard is acting up it is the first sign of power issues.

 

Adam

[rolanaj]

It's not really that the keyboard acts up so much as the keys are spongy(?) and the layout is a little strange. You kind of have to really smash the keys sometimes to type. The usb hub I have doesn't have a power supply at all so I have to replace it.

[zlim]

I have one of those keyboards too. It is so old it has a PS/2 connector. I know what you mean about the spongy keys. I bought it to connect to a laptop. I kept my laptop safely away from my coffee cup because I did not want an accident and was willing to put up with the spongy keys so I could compute and drink coffee.

[ross549]

It's not really that the keyboard acts up so much as the keys are spongy(?) and the layout is a little strange. You kind of have to really smash the keys sometimes to type. The usb hub I have doesn't have a power supply at all so I have to replace it.

 

I agree. The keyboard I have for my Pi is not very good either. Logitech K400. It is wireless and works week aside from the sponginess.

 

I wish dell mad a simple wireless keyboard based on their normal keyboards and not a slim keyboard.

 

Adam

[rolanaj]

I thought the roll up one would be good for the little one to use because it wouldn't matter if she spilled stuff on it.

 

I had to replace the keyboard for my PC a year or so ago and it is fine except when I want a capital letter, then I have to make sure to jam the caps lock key down and hit the letter I want capitalized really hard. The letter i seems to be the worst one, beyond annoying but I'm too cheap to replace it yet. I have other keyboards kicking around but they have the PS/2 connectors and I'd need an adapter.

[abarbarian]

I got me an empty large plastic water cooler bottle about fifteen years ago with the intention of filling it with loose change an then buying meself a huge treat. I never got more than an inch or two of the bottom covered as I kept on dipping into it. So today I emptied it and took the swag to the local store which has a change converter machine. Shocked I was when I looked at the total, £42.57. Recovering quickly I dashed home and ordered one of the Pi cameras that will be on sale tomorrow. I'd had a early interested party e-mail from Farnell earlier in the day hence the hunt for loot.Whilst I was in town I took the opportunity to bank a cheque I received yesterday from the local scrap yard where I had taken a trailer load of scrap to weigh in. £15 I got for a load of old tat that folk have over the last few years have paid me small amounts of loot to dispose of. I was shocked to discover that Farnell's were wanting to charging £4 more than RS for my order. What order you say,thought you were only getting a camera ? Did I not mention a camera ? How remiss of me.I just did a quick proof read and I did mention a camera, I thought I had.Anyways, adding up £15+£42.57=£57.57 which was less than Farnell wanted but more than RS wanted I spent the difference on a chicken wellington which was reduced to half price and a glorious fresh cream horn.So here I sit well fed and watered, I found a half bottle of mulled wine at the back of a cupboard this evening, feet up and waiting. Me version B latest model Pi with translucent case and camera module should arrive in a few days time. I should have recovered from todays exertions by then.

I'll post pics.

Just been reading through the RaspiCamDocs. This looks like some piece of kit.

 

 

http://www.raspberry...ag/camera-board

 

http://www.raspberry...g/archives/3890

Edited May 14, 2013 by abarbarian

[abarbarian]

You have a shipment being sent from RS COMPONENTS LTD that is due to be despatched on 15/05/2013 using our Express 24 service.

 

Looks like it may arrive today.

[abarbarian]

Icky thump ! Not ten minutes after me last post a jiffy bag was pushed through the letter box. I'll be posting pics.