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by chrisprt
Thu Dec 20, 2012 4:38 pm
Forum: Other projects
Topic: Truecrypt Seems to work pretty well
Replies: 44
Views: 43209

Re: Truecrypt Seems to work pretty well

Hi all, i have created a truecrypt image with the following command sudo ./truecrypt -t --create /pi/media.img --password=123456 --volume-type=normal --encryption=AES --hash=Whirlpool --filesystem=vfat -k "" --random-source=/pi/mKey.txt --size=1000000000 I failed to mount it with the following comm...
by chrisprt
Thu Dec 13, 2012 1:09 am
Forum: Other projects
Topic: Truecrypt Seems to work pretty well
Replies: 44
Views: 43209

Re: Truecrypt Seems to work pretty well

mattborja wrote:You guys do know you can also just download the guy's compiled binary here: http://reinhard-seiler.blogspot.co.at/2 ... e-for.html
true, unless you want to use it on an armel install. If anybody has that problem I can post the binary I compiled.
by chrisprt
Mon Dec 10, 2012 12:22 am
Forum: Other projects
Topic: Truecrypt Seems to work pretty well
Replies: 44
Views: 43209

Re: Truecrypt Seems to work pretty well

For everyone having trouble mounting their formatted containers, create the volume with NO filesystem. After that's done, mount the file with --filesystem=none, which will merely create a /dev/loop1 device. After that, use the common filesystem formatting tool for your desired filesystem (e.g. mkfs...
by chrisprt
Sun Dec 02, 2012 7:21 pm
Forum: General discussion
Topic: 512 MB, worth the upgrade?
Replies: 11
Views: 3338

Re: 512 MB, worth the upgrade?

For me, yes. I have a lot of existing code written in managed languages (C#, Java) that take up a decent amount of memory. mono and the JVM tend to be memory hungry.
by chrisprt
Mon Nov 26, 2012 11:29 pm
Forum: Other projects
Topic: Truecrypt Seems to work pretty well
Replies: 44
Views: 43209

Re: Truecrypt Seems to work pretty well

For everyone having trouble mounting their formatted containers, create the volume with NO filesystem. After that's done, mount the file with --filesystem=none, which will merely create a /dev/loop1 device. After that, use the common filesystem formatting tool for your desired filesystem (e.g. mkfs....
by chrisprt
Mon Nov 26, 2012 6:37 am
Forum: Other projects
Topic: Truecrypt Seems to work pretty well
Replies: 44
Views: 43209

Re: Truecrypt Seems to work pretty well

I get the error "Error: mount: you must specify the filesystem type", and when I try specifying it manually it fails with "Error: mount: wrong fs type, bad option, ...". How did you create the volume? I created one in the boot partition for testing using the following command: ./truecrypt -t --crea...
by chrisprt
Sat Oct 27, 2012 3:43 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

deltalima wrote: Isn't pps-ktimer a test and not synched to the PPS coming fro the GPS?
Yes. Found in pps-ktimer.c:

Code: Select all

/*
 * pps-ktimer.c -- kernel timer test client
by chrisprt
Sat Oct 27, 2012 3:41 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

Yes, when I do modprobe pps-gpio I don't see /dev/pps0 created I did modprobe pps-ktimer as a test, that created /dev/pps0 and ntp synchs, but this is a test and the PPS is not synched to the pulse coming from the GPS unit. Hmm, that is odd. check dmesg and tail all of the log files. There should b...
by chrisprt
Fri Oct 26, 2012 8:00 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

hey all, thanks everyone I successful make a first support PPS kernel, it work very well. [/quote] Awesome! congrats! [quote="peterwillcn"] [b]Join the pool.ntp.org project [/b] Thanks for your interest. Usage of the pool has grown enormously and the only way we can keep it easy for everyone to run...
by chrisprt
Fri Oct 26, 2012 7:51 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

deltalima wrote: If I modprobe pps-ktimer, /dev/pps0 and /dev/gpspps0 are created and ntp synchs to the test PPS signal, however if I dont use pps-ktimer the devices are not created all I see is
...

pps-gpio in /etc/modules

Am I missing something?
modprobe pps-gpio, not pps-ktimer.
by chrisprt
Tue Oct 23, 2012 1:17 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

hey, shdosf how to loading the pps_gpio and pps_core modules? can be described in detail? Here's some code I wrote in the beginning to make sure the module was loaded and the symlinks were made for the GPS_NMEA() clock in NTPD. echo "Checking to see that pps-gpio is loaded " res=`lsmod | grep pps_g...
by chrisprt
Wed Oct 17, 2012 2:42 am
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

As promised, I've attached the pps.patch file which should aid anyone who plans to recompile the kernel with PPS support. Download the latest raspberry pi kernel, apply this patch from the linux directory, and then go through the normal compilation process. Make sure to enable all the relevant PPS d...
by chrisprt
Mon Oct 15, 2012 7:05 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

Hi Chris, Thanks for your plots. Mine can be found at http://secondthoughts.no-ip.org/ntp/index.php I rarely see my pi drift off more than a couple of microsecs, and I have pretty much followed your guide, so am interested why we see a difference. I am using the suregps which has a 3.3v pps so no n...
by chrisprt
Mon Oct 15, 2012 3:35 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

All, I saw the posts asking for a new kernel image and realized that I went through the arduous process a few weeks ago. I've compiled the newest kernel as of about 3 weeks ago: [email protected] /lib/modules $ uname -a Linux raspberrypi 3.2.27-pps-g965b922-dirty #1 PREEMPT Sat Sep 22 16:30:50 EDT 2012...
by chrisprt
Sun Oct 14, 2012 11:59 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

And for people interested in my build, Here's a screenshot displaying the major parts: http://i.imgur.com/aWV8Q.png http://i.imgur.com/aWV8Q.png It's composed of an Adafruit raspberry pi prototyping plate, a simple DB9 breadboard connector, an LD33V voltage regulator, and a MAX3232 SMD chip. The har...
by chrisprt
Sun Oct 14, 2012 11:36 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

All, I've been working on a hardware solution for this for the past month (I'm terrible at electrical engineering), and I've finally got it working. For those interested, I've attached the last 3 days' loopstats in graph form. I think stability could be a lot better, but the pi is currently housed i...
by chrisprt
Sat Aug 25, 2012 4:25 am
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

Hi Chris In my experience the offset on the NMEA data has always been quite large. That 432.26 represents milliseconds, right ? Yes, offset is expressed in milliseconds. That's not too surprising from the NMEA serial side though. For example, my Garmin GPS 18x LVC NMEA data is 600 milliseconds earl...
by chrisprt
Fri Aug 24, 2012 7:16 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

remote refid st t when poll reach delay offset jitter ============================================================================== oPPS(0) .PPS. 0 l 14 16 377 0.000 -15.084 3.718 +SHM(0) .NMEA. 0 l 45 64 7 0.000 -432.26 5.229 *41.216.193.26 ( 41.73.40.11 2 u 34 64 17 37.625 -10.666 11.477 :D That...
by chrisprt
Wed Aug 22, 2012 1:55 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

I tried the voltage-divider + GPS-PPS in series idea and... it works :D :D . I've been running ppstest for a few minutes and it hasn't shown any dropped pulses. Nice! You'll have to get the ntpd source and build it for the type of driver support you'll need, but it should be smooth sailing from here.
by chrisprt
Mon Aug 20, 2012 12:17 am
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

ADAFruit makes an interesting GPS module : http://adafruit.com/products/746 . It runs off 3.3V to 5V and it runs TTL for rx/tx and pps. It only uses 20ma when running. I've ordered a couple of these for my Pis. If I had a clear view of the sky without having to hang my GPS up in my window I'd be al...
by chrisprt
Sun Aug 19, 2012 12:41 am
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

For those interested, I ran the pi while being synced to my GPS unit for a 24 hour period. Here's the results: http://i.imgur.com/ruN5P.png It stayed pretty stable throughout the day, only drifting around 20 microseconds max in either direction. The room that the pi in has pretty large heat fluctuat...
by chrisprt
Fri Aug 17, 2012 7:52 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

Yes, you could use a resistive divider to DC bias at 0.5 V and a capacitor to the weak PPS source to give you the AC portion of the signal. I'd expect the Pi input logic threshold to be at 3.3/2 = 1.65 volts, so if you are really getting 2.7 V I'd expect it to work consistently. Although the thresh...
by chrisprt
Fri Aug 17, 2012 2:56 pm
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

I checked the manual for my Trimble Thunderbolt it states that the PPS voltage is 2.7 V... what is the triggering threshold for the Pi's GPIO pins when used as inputs ? The GPIO pins expect 3.3v, but I don't know the exact triggering threshold for the pin. I did a little googling but couldn't find ...
by chrisprt
Thu Aug 16, 2012 12:46 am
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

I've been on vacation, but came back and after some fiddling I may have it working! Due to the problems encountered while using the ATOM driver, I decided to take the advice of others and purchase a serial port to USB adapter. Using the adapter, I was able to successfully retrieve the GPS time sente...
by chrisprt
Tue Aug 07, 2012 12:48 am
Forum: Other projects
Topic: NTP PPS
Replies: 285
Views: 130335

Re: NTP PPS

In this case the peak error gets about 30x smaller, from 2 msec down to 0.06 msec. the accuracy limitation with PPS is the variable interrupt latency on the R-Pi. 60 microseconds sounds pretty good right about now. Congrats! One more thing, here's the tar file for all the modules gathered from the ...

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