I am writing some SDcard driver for logging of GPS position and radiation (from a PIC). I can write something human readable like year[1] month day time longitude latitude counts_per_minute yyyy mm dd hh:mm 123 01234.567 E 7 01234.567 S 65536
This is less than 64 bytes per entry, on an 1GB old SDcard with 512 bytes per sector, and not using any [for example MS freaking FAT] filesystem, that makes 8 entries per sector, so when storing radiation in counts per minute once per minute,
16 minutes per kB, is 16,000 minutes per MB, is 16,000,000 minutes per 1GB card[2], works out to
16,000,000 / (60 * 24 * 365) = 30.4414 years. :-)
Now about the batteries, well I use solar with Lipo, the FLASH lifetime and battery lifetime come into play, and strong radiation will empty the FLASH I am sure, and I do not remember how long WW3 lasted.
Better provide an on board read mechanism, RS232 will be around for an other 30 years I think... not so sure about SDcard readers. [1] see why? [2] Actual sd 8:0:0:0: [sdb] 1970176 512-byte logical blocks 1008730112 bytes, not sure all are writable.
[3] All this philosophy cause I am waiting for SDcard connectors. But it _is_ a lot.
Maybe pick some long error-correcting code and store things for 15 years much more reliably?
I kinda like the idea of treating it as dynamic RAM -- if you work out a schedule so that no sector gets left alone for more than a month or something, and move things around then you'd protect it from soft errors due to radiation, and with read-back you could protect it against hard errors, too.
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Tim Wescott
Control system and signal processing consulting
On a sunny day (Sun, 12 Jan 2014 09:12:22 -0700) it happened RobertMacy wrote in :
It is the same with optical media. I have a big light proof box with very old burned CDs, old DVDs, and more recent BluRay disks, added 6 or so BluRays today, imagine Goldfinger (bond) in HD without adds recorded last night from German TV, plus Thunderball, together on one BluRay, Anyways the box holds 1000 disks, is almost full, Now I can put about 30 700 MB CDs on 1 22 GB or so BluRay BD-R-25, that way creating space in the box, and refreshing the data in the process. Refresh cycle is now about 12 years....
Germany ZDF seems to be the only station that transmits these A movies in HD without commercials free to air (satellite). Bond in German of course, found 3 audio channels, one AC3, but no original sound, but it is very well done really, absolute top.
On a sunny day (Mon, 13 Jan 2014 19:01:40 +1100) it happened Chris Jones wrote in :
Yes, hard to tell, same for PIC FLASH, but for that you can make a backup copy. and compare and restore that, Last night I scored some 24LC1025 FLASH EEPROMs on ebay, from a software POV the PIC I am using only has 256 bytes of RAM, and I am using lots of it for GPS NMEA parsing already, so data will go to that EEPROM on a 1 minute basis, it will hold 128 kB, is 128*16 minutes, or (128*16)/60 = 34 hours, enough for a day prospecting in the boonies of kangaroo land for example, that then can be read via RS232 into the laptop, but also allows me to collect and write a full sector to SDcard even though I do not have the RAM. Without SDcard and with only this chip, the whole thing can be extremely small, like the size of a small flashight or laser pen. And I already wrote all the code, also for those EEPROMs, as I use the smaller version in tri_pic:
formatting link
That has now run for 1.5 years, logging every hour...
On a sunny day (Mon, 13 Jan 2014 06:13:01 -0600) it happened "Tim Williams" wrote in :
Thank you Tim, that is interesting, send command 63 and APPO ...
I had a few Chinese USB memory sticks that do not do what they claim... and ended up dead after I tried those on my laptop USB3 port... So now I only buy cards and USB memory sticks locally (from opus.nl).
8051 hey, now that is old... Probably a bit of work needed to figure out a cards unlock code.
Using six decimal places on longitude and latitude gives you a resolution of about 11 cm at the equator. For positive lat/lon, leave off the '-' for additional space savings.
At 46 characters, you can fit 11 readings per 512-byte sector, so you have (11 * 1,970,176) / (60 * 24 * 365.25) = 41.69 years!
Some other ideas:
You might put some kind of header character, $ or whatever, on each record. That way if you do get some corruption in the next 30 or 40 years, it's easier to scan to find the beginning of the next record.
You might have it print a column label once a day, or at the beginning of the data, or whatever... you might not remember all the columns in
30 years. :)
Agreed.
Probably true. Wikipedia (would they lie to you?) says it was introduced in 1962, so it's lasted 52 years so far. Current-loop is older and is (I think) still hanging around, too.
On a sunny day (Tue, 14 Jan 2014 05:34:35 +0000 (UTC)) it happened snipped-for-privacy@att.net wrote in :
Yes, that is nice , but as to position, the GPS module I am using has a resolution of about 10 meters. The NMEA format for one of the responses I am using is: ; GGA-Global Positioning System Fixed Data ; Table B-2 contains the values for the following example: ; $GPGGA,161229.487,3723.2475,N,12158.3416,W,1,07,1.0,9.0,M,,,,0000*18 ; Table B-2 GGA Data Format ; Name Example Units Description ; Message ID $GPGGA GGA protocol header ; UTC Time 161229.487 hhmmss.sss ; Latitude 3723.2475 ddmm.mmmm ; N/S Indicator N N=north or S=south ; Longitude 12158.3416 dddmm.mmmm ; E/W Indicator W E=east or W=west
As I only use one PIC 18F14K22 I am really proud I have been able to write a NMEA parser that only uses a few bytes RAM, has a real time clock synced if it sees GPS time, does voltage regulation and PWM generation for the GM tube, has a character generator and color LCD driver, I2C data storage to 24LC1025 EEPOM for 31 hours, SD card driver, help menu, probably forgot some things, and RS232 out, RS232 in, completely software configurable, settings saved in EEPROM, and code space to spare. Changing the output format would require some more math (I have 32 bit integer math on board). There is also (what I forgot) a level alarm, dosage alarm, alarm beep, tick on counts, what not, battery monitor, All written in PIC 18 asm of course. I still have to test the SDcard driver in C, and then port that to asm, waiting for some card sockets. No reason it should not work, it is based on the mmc3.c code on my site for the WAP54G webserver SDcard extension I made:
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The GM part part is mostly based on this:
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The i2c EEPROM part uses code from this:
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The GPS NMEA parser is from my 'drone' project, and IIRC also somewhere on the website, at least the initial version It is cool to put all those code parts together (some need porting from 16F to 18F PIC), and last night I had some test running with GPS for hours to test clock and time sync, and was surprised it worked so well..
As to a noble gas poster here who is clueless to modern design, to make chip rad-proof, for ME, is very simple: Take PIC and EEPROM (DIL), fold back pins, solder on decoupling cap, solder on flat cable, wrap in lead foil (from local plumber shop), it is not much bigger, it IS a little bit heavier, now put your Xray source on it... I am not using it in space, or in a vacuum, so that is all that is needed, to make it rad-hard. Sometimes I wonder.... Anyways with THAT much radiation the user would not live for long, no fear he wants his money back. Reality rules This is a design group, 'man saying it cannot be done should not disturb man do doing it' (or so I have read here). I will probably put the source and circuit diagram out under GPL too some day, unless it is bought first. Maybe some silly piratebay user will download it and use it in their latest gadgets, code protected of course, until the FSF gets the smell of it, so respect the GPL.
Back to you, Mr Roberds, yes, there is in fact already such a marker, it is the Unix linefeed (LF, ASCII code 10).
Yes, I could use comma separated fields too, so it can be easier entered into a spreadsheet perhaps, but I will write a small C program to parse it using scanf I am sure.... I already wrote some C test code...
Yes, may be every few lines or so, that helps in reading Sure, 30 years, I likely will not be around then, so that is you guys problem :-)
Just use tab for the white space separators and Office etc will parse it by default. You might want to consider using the trailing spare bytes in each record to store an error correcting code. Typically to correct any single bit error and detect any two bit error.
Every now and then you can have the idle process check for degradation. (once a month should be good enough) Flash memory is good but not quite perfect the odd secondary cosmic ray fragment reaching ground level can flip a bit if you wait long enough and lead foil won't stop them.
I'd be inclined to store everything in binary with aggressive error correcting codes - the smaller the memory footprint used and the more extensive the ECC the harder it is for a single bit flip error to get past unnoticed. The chips themselves do something similar in hardware.
On a sunny day (Tue, 14 Jan 2014 14:00:55 GMT) it happened snipped-for-privacy@puntnl.niks (Nico Coesel) wrote in :
mm, so you do not have HD yet?
KPN is a dead duck run by control fanatics who did not move with the times, old copper wire freaks, who think 'K' (for Koninklijke (= Royal)) is a ticket to dictate the users. It was a Royal pain in the ... to put it mildly.
I have cable now, I think they changed it to max speed the modem can do. Had to download a huge file some weeks back, zaaap, huh???? For movies I have a satellite dish, and DVB-S2, hardly ever watch cable TV, so few times I had to re-activate my card a while back....
I still have the old KPN modem, and I even had the old viditel modem (1200Bd / downlink, 75 Baud uplink)... Those worked OK, the ADSL modem was a power eater, same as the cable modem now (30 W??).
I sincerely hope Slim gets full control and changes KPN into a real company, where users are king, but it is possible the control freaks will want to keep in control, and then they will keep losing customers year after year, after year, for their copper landlines. Until it finally evaporates.... Slim maybe wanted the wireless part, and that will cost him dearly to upgrade everything to LTE. And after that to the next system, and the next.... KPN is, well ......, maybe Microsoft can buy it, maybe not....
Ofcourse. I'm watching on a HD monitor. The problem is that TV streams need realtime encoding so the compression is crappy. What I download is compressed using much better (but slower) compression algorithms.
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Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
On a sunny day (Tue, 14 Jan 2014 16:27:09 GMT) it happened snipped-for-privacy@puntnl.niks (Nico Coesel) wrote in :
Strange, I think most programs come from harddisk these days, either copied from an original DVD or Bluray, or perhaps recorded from a 35 mm film scanner. Modern movie theaters use digital projectors these days, and the movies are supplied as digital masters, it is possible, but I am not sure, the broadcasters just get the digital versions. I can assure you that those 4k x something are top quality encoded.
I am not sure about ZDF, but IIRC they went all digital HD years ago. BTW mpeg2 compression, or H264 can be really good these days, all FPGA work. You can buy that IP from a.o. Altera. And the high end newer graphics cards have the hardware encoders. I have done a lot of encoding, it used to be DivX, and I have a lot of DivX HD encoded 2 pass material. and then with decent de-interlacing, much better than the teevee does. IIRC my Samsung 46 inch HD LCD plays it, it actually runs Linux, I have the sources too, but really no time and longing to delve into it, although I would like to install xine and mplayer on it...
Most of the stuff I have seen from youtube was not really that good... they seem to do HD though.
But it still needs to be compatible with was is being encoded in real time (news, live television, football matches) and what the settop boxes are capable of decoding. Every now and then I need to update the codecs on my PC to be able to play movies/TV series encoded with the newest compression.
Youtube and quality -sigh- Apples and oranges...
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Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
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