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by bryanandaimee
Wed Mar 15, 2017 5:37 am
Forum: General discussion
Topic: Pi Day
Replies: 24
Views: 6943

Re: Pi Day

Strangely my new Pi3 is not a great pi calculator.

I get 36 seconds for 3,141,593 decimal places vs. 20.5 seconds on the Pi2.

Perhaps an optimization issue?
by bryanandaimee
Tue Mar 15, 2016 7:07 pm
Forum: General discussion
Topic: Pi Day
Replies: 24
Views: 6943

Re: Pi Day

Perhaps I was being too cute with the reporting format. The final calculation in the list (35pi million DP) comes to about 109.96 million decimal places. This calculated on Mathematica in 1527 second or 25.5 minutes. The calculation was done without swap. I doubt you would be able to get much furthe...
by bryanandaimee
Tue Mar 15, 2016 5:40 am
Forum: General discussion
Topic: Pi Day
Replies: 24
Views: 6943

Re: Pi Day

Pi day again. Gotta calculate pi. I ran the mathematica calculation on a B2 this year with 16MB video memory to maximize the CPU memory. The calculation only took 25% CPU so it is obviously not multi-threaded. No big deal since the calculation is still very much memory limited. On a B2 this year. I ...
by bryanandaimee
Sat Mar 14, 2015 8:56 pm
Forum: General discussion
Topic: Pi Day
Replies: 24
Views: 6943

Re: Pi Day

In honor of the special once a century pi day I repeated the above calc on a B+ with maximum memory allocated to the CPU. I got clear up to 5.654866 x 10^7 decimal places of pi. Calculation took 1662 seconds using a standard turbo mode at 900 Mhz. No other overclocking features were used. Maybe next...
by bryanandaimee
Thu Sep 25, 2014 5:36 pm
Forum: Advanced users
Topic: Overclocking
Replies: 1125
Views: 573089

Re: Overclocking

1700 Mhz, very nice! That looks like a new world record to me. I haven't seen anyone report a higher value yet. If you want it to go 1700Mhz all the time you have to set force_turbo=1 in the config file. Otherwise you will get the CPU alternating between 700 and 1700 as you report depending on the l...
by bryanandaimee
Wed Sep 03, 2014 5:16 pm
Forum: Advanced users
Topic: Overclocking
Replies: 1125
Views: 573089

Re: Overclocking

Very nice! Keep it simple. Once you do that though I don't think over_voltage settings do anything. You'll notice your ring_osc readings won't change no matter what you do to the over_voltage setting. It will report an erroneous voltage based on the over_voltage setting but the actual ring_osc frequ...
by bryanandaimee
Fri Aug 15, 2014 9:58 pm
Forum: General discussion
Topic: 1500MHz lock?
Replies: 43
Views: 10402

Re: 1500MHz lock?

Well I did get to 1450 MHz but I'm still fighting SD card corruption issues at higher core voltages. It helped a little to separate the 5V supply from the core supply. Not sure what problems that might cause though with 5V starting up one or two seconds before the core voltage. I set the core clock ...
by bryanandaimee
Fri Aug 15, 2014 9:43 pm
Forum: Advanced users
Topic: Overclocking
Replies: 1125
Views: 573089

Re: Overclocking

In response to the request for suggestions on how to get past 1230 MHz. Check out the volt modding discussion. It's not hard. I did it myself with an LM317 circuit to give variable core voltage control. You do have to remove an inductor from the board so if you're SMD challenged then beware. I have ...
by bryanandaimee
Fri Aug 15, 2014 9:38 pm
Forum: Advanced users
Topic: Electrician need helped ( Voltage mod)
Replies: 5
Views: 2520

Re: Electrician need helped ( Voltage mod)

Here is a forum topic on volt modding the pi. It's been done at least twice now and confirmed by dom, so it's legitimate. I saw the article on the web and decided to give it a try on the cheap and it works just fine. I'm getting SD card corruption at higher voltages (above 1.9V). http://www.raspberr...
by bryanandaimee
Fri Aug 15, 2014 8:59 pm
Forum: Advanced users
Topic: Determining how fast your Pi really is
Replies: 62
Views: 14229

Re: Determining how fast your Pi really is

My guess would be that if you set overvolt to 8 (highest setting) you would be able to get to 1200 or 1250 stable. That is a very fast Pi. Preliminary tests on one of my 2 new Pi B+ gives 3.024 MHz ring osc. at 1.20 V and 975 max stable overclock at that voltage. I would have taken it to 1.4V but it...
by bryanandaimee
Fri Aug 15, 2014 8:45 pm
Forum: General discussion
Topic: Stock at MCM Electronics
Replies: 166
Views: 22879

Re: Stock at MCM Electronics

Just to add to the discussion since MCM seems to be monitoring this forum. I bought two RasPi model B+ recently from MCM when shipping was $5 to the US. When the Pi(s) arrived they were in a bubble padded envelope rather than a box. One of the Pi had a bent USB housing, I assume from being crushed d...
by bryanandaimee
Wed Aug 13, 2014 4:21 pm
Forum: General discussion
Topic: 1500MHz lock?
Replies: 43
Views: 10402

Re: 1500MHz lock?

Doesn't look like a power supply problem. I'm getting SD card corruption at higher core voltages regardless of which power supply I use. Of course it might be the LM317, but I'm goint to try setting core freq back to 250 and try a couple different SD cards next.

Bryan
by bryanandaimee
Mon Aug 11, 2014 12:16 am
Forum: General discussion
Topic: 1500MHz lock?
Replies: 43
Views: 10402

Re: 1500MHz lock?

2014-08-10-1400MHz 1.8V.jpg Well I was able to volt mod the Pi with just an LM317 for the core voltage control. I was able to get to 1400 MHz using my ghetto setup. That was at 1.8V. I can't seem to get above that stable with my current setup even at higher voltages. I am using a wall wart supply s...
by bryanandaimee
Fri Aug 08, 2014 3:42 pm
Forum: General discussion
Topic: 1500MHz lock?
Replies: 43
Views: 10402

Re: 1500MHz lock?

Hmm, is the 256M GPU setting going to play havoc with my old 256M model B?
by bryanandaimee
Wed Aug 06, 2014 4:00 pm
Forum: General discussion
Topic: 1500MHz lock?
Replies: 43
Views: 10402

Re: 1500MHz lock?

Wow Dom, that is a lot higher than I would have thought to go. With 100 MHz per 100mV, 1500 MHz doesn't sound too hard. That's what I see on mine too. Going from 1.2 to 1.4V, I get 950 to 1150 which is right at 100 MHz per 100mV. So on mine that would translate to over 1500 MHz at 1.8V just as repor...
by bryanandaimee
Tue Aug 05, 2014 10:29 pm
Forum: General discussion
Topic: 1500MHz lock?
Replies: 43
Views: 10402

Re: 1500MHz lock?

Any idea if this voltage mod is legitimate? Looks like the guy is a writer for an online tech news site so I'm inclined to give him the benefit of the doubt. Also it looks like he did some benchmarking. http://us.hardware.info/news/38967/hardwareinfo-pro-oc-overclocks-raspberry-pi-to-15-ghz http://h...
by bryanandaimee
Tue Aug 05, 2014 4:14 am
Forum: Advanced users
Topic: Determining how fast your Pi really is
Replies: 62
Views: 14229

Re: Determining how fast your Pi really is

For my old 256 meg model B At 1.20V I get 3.004 MHz at 45 degrees core temp. 950 core is the best I get at 1.20V and 1150 is marginally stable at 1.40V RingOsc.jpg Also from gathering a little data it looks like the ring oscillator frequency does change versus temperature. Also the frequency change ...
by bryanandaimee
Sat Jul 26, 2014 12:26 am
Forum: General discussion
Topic: Pi Day
Replies: 24
Views: 6943

Re: Pi Day

Just found a post on Mathematica about calculating pi and it looks like that speeds things up quite a bit. Code below: (*Clear Cache*) ClearSystemCache[] (*Calculate pi to 1 million decimal places and store the result*) AbsoluteTiming[pi = N[Pi, 1000000];] On the same setup as before I got: pi milli...
by bryanandaimee
Fri Mar 14, 2014 2:14 pm
Forum: General discussion
Topic: Pi Day
Replies: 24
Views: 6943

Re: Pi Day

How many digits per day could a beowulf cluster of 314 Pi's calculate? The world may never know. Turns out that my Pi runs out of memory after only 20 minutes or so and kills the process. So the max number of digits I can calculate is something like 20 million. The 512 MB Pi's could probably do quit...
by bryanandaimee
Fri Mar 14, 2014 3:49 am
Forum: General discussion
Topic: Pi Day
Replies: 24
Views: 6943

Pi Day

I figured I ought to do something with the Pi for Pi day (3/14) so i installed Pi on my Pi, sudo apt-get install pi then i calculated Pi on the Pi to 3.141593 (rounded) million decimal places. pi 3141593 > pimil.txt The calculation took 132 seconds on my old Pi (256 MB version B) running at 1100 Mhz...
by bryanandaimee
Fri Jan 10, 2014 5:36 pm
Forum: Teaching and learning resources
Topic: Raspberry Pi Educational Resources
Replies: 12
Views: 4607

Re: Raspberry Pi Educational Resources

I'm a former teacher, but I've been thinking about Pi in the classroom lately. I think as a start, a teaching resource should be 1. Fun 2. Include well thought out assignments with notes for teachers, grading rubric, handouts, etc. 3. Include additional challenges for advanced students that get done...
by bryanandaimee
Tue Oct 01, 2013 6:47 pm
Forum: Gaming
Topic: Low res games
Replies: 2
Views: 647

Re: Low res games

So far I've just tried the native games like supertux and rafkill. Most of them seem to be running at about 640x480 so it's pretty small on a 1080p screen. I haven't looked at emulators yet.

Bryan
by bryanandaimee
Sun Sep 29, 2013 4:56 pm
Forum: Gaming
Topic: Low res games
Replies: 2
Views: 647

Low res games

seems like most of the games I've tried for my kids on the Pi are low resolution and therefore play in a very small window on my HDTV. I'd rather not have to go change screen resolution just to play the games at a better size. Is there an easy way to enbiggen (bigify?) these games without messing up...
by bryanandaimee
Wed Sep 11, 2013 2:40 am
Forum: Python
Topic: question about pylirc
Replies: 9
Views: 3144

Re: question about pylirc

Oh, and I forgot to add the receiver generally inverts the logic of the signal. It outputs a high voltage while nothing is happening and then outputs a low voltage when a signal is detected. The modulation gets stripped out and you are left with a logic level pulse without the carrier.
by bryanandaimee
Wed Sep 11, 2013 2:35 am
Forum: Python
Topic: question about pylirc
Replies: 9
Views: 3144

Re: question about pylirc

I would think you would want a modulated IR signal like the remote receivers are expecting. Otherwise the range and sensitivity are going to be very low and the noise immunity will be poor. The whole point of modulating the signal before adding the binary data on top is to allow the receiver to reje...

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