3D Printing Filament Spools

Today I have been working on my relatively new 3D Printer; a Creality K2 Plus.  I have started printing filament spools to be used with Filament Refills.  Filament in refill form is much cheaper and I do not have to throw away the empty spools when done. I will soon share some photos, maybe.

--

-- Home Page: https://WA0UWH.blogspot.com

It has been a while.

​Yes, it has been a while since I have posted on this blog, primarily because my interests have wandered into many other topics or areas. I still enjoy the Ham Radio Topics, but I may stray into other areas if I continue with this blog.

I now spend most of my free (retired) time in: software development, 3D Printing, wood-working, machine-shop and science in general.  My immediate interest are: Linux OS, HomeAssistant, high precision GPS locating, Meshtastic, home and remote networking with Tailscale, and Rustdesk.

I am also interested in maintaining my current Window 10 and Window 11 workstations, trying to Debloat them to keep them usable and worthwhile to have around, I found WinHance works well for that.

Some time after my last post, my dog "Tess" crossed the rainbow bridge, and my good friend "Larry Littlefield" also passed away about the same time as Tess (in 2020). Larry was always a good contributor to my projects and always had something interesting working on his own projects.  Sence larry's passing, I have found it very hard to find someone that has similar interests, most of my work is now on projects alone.

Two years after Tess crossed, I now have a new pup, her name is Tammy, she is now 4 years old.   

I may try to keep the blog alive, depending on effort and interest.

-- Home Page: https://WA0UWH.blogspot.com

More Projects with Telegram

In the past years I had always blogged my projects, but due to time, effort and format I had stopped doing that.   But my projects continued, and I have collected many photographs of them.  I missed the interaction with readers of my blog and have always wanted a simpler method.  

I think I have found one: by using "Telegram Channels" , they are simple to setup, and very easy to add content.  The one thing lacking is: "No Re-Arrangement" of content, once created and posted, only edits of text (or post deletions) is possible (but I can live with that).  It is simple, just:  take a photo, share to the Telegram Channel with a little text, and it is DONE (maybe 15 sec of effort).

So this is what I have done with a lot of previous un-posted photos, and I will continue to add new photos and text as progress permits.

Telegram is normally a social communication APP available for a phone and/or most other hardware.

The Telegram Channel that I have set are easy to follow, or can be viewed via a workstation browser, as they also have a very short Public link.   I have named my group of Channels as "MrFab_<subject>", where the index is a Channel called "MrFab_Index",  it can be searched for on Telegram.  Or, use the Public Link URL as: 

http://t.me/MrFab_Index

This Channel is the Index page for all of my actual Project Channels. If you use the URL in a browser, there will be a button to "Preview Channel" and therefore a new user does not actually have to install the Telegram APP to view the content.

Finding and developing this Idea was in itself a fun project, I hope I can keep it up. 

If you would like to see my projects feel free to join, or follow as desired.

Also, feel free to use this Idea to create your own Project Channels, I think you will find it enjoyable and easy. It will provide a historical record of your Projects. If needed I will help with some ideas and pointer to start your efforts.

Let me know if you find the useful or fun, also feel free to share the URL Link above,  thanks.

This Channel is the Index page for all of my actual Project Channels. If you use the URL in a browser, there will be a button to "Preview the Channel" and therefore a new user does not actually have to install Telegram to view the content.

Finding developing this Idea was in itself a fun project, I hope I can keep it up. 

If you would like to see my projects feel free to join, or follow as desired.

Comments Welcome and encouraged via the Telegram APP.

But inappropriate comments will be deleted, Spam and Trolls will be banned with out notice.

Also, feel free to use this Idea to create your own Project Channels, I think you will find it enjoyable and easy. It will provide a historical record of your Projects. If needed I will help with some ideas and pointer to start your efforts.

Let me know if you find the useful or fun, also feel free to share the URL Link above,  thanks.

-- Home Page: https://WA0UWH.blogspot.com

More Phi

More Phi

Phi is about 1.61803.....  (see previous post)

Interesting values in the following formula;  A^2-A

A=1;  A^2 - A = 0.0000....

A=1.60;   A^2 - A = 0.9600

A=Phi;  A^2 - A = 1.0000....

A=1.62;  A^2 - A = 1.0044

A=2;  A^2 - A = 2.0000....


For all other number besides Phi, with this formula, will equal something other than 1.00000....

Also interesting;

A=Phi; A - (1/A) = 1.0000....

Phi in terms of  "1";

Phi = (1+sqrt(1+1+1+1+1)) / (1+1)



-- Home Page: https://WA0UWH.blogspot.com

More Phi

As seen in my previous post, I enjoy special numbers. Phi is similar to Pi, as it never repeats.  As seen from the previous post it is easy to print the value of Phi for as many digits as you like. On my Linux Workstation it took 199 minutes,59 seconds to compute and print.

Here are the first few and the last few of 1,000,000 digits.


/home/eldonb
Dogee$ time echo "scale=1000000;((1+sqrt(5))/2)" | bc
1.618033988749894848204586834365638117720309179805762862135448622705\
26046281890244970720720418939113748475408807538689175212663386222353\
69317931800607667263544333890865959395829056383226613199282902678806\
75208766892501711696207032221043216269548626296313614438149758701220\
34080588795445474924618569536486444924104432077134494704956584678850\
98743394422125448770664780915884607499887124007652170575179788341662\
56249407589069704000281210427621771117778053153171410117046665991466\
97987317613560067087480710131795236894275219484353056783002287856997\
82977834784587822891109762500302696156170025046433824377648610283831\
26833037242926752631165339247316711121158818638513316203840052221657\
91286675294654906811317159934323597349498509040947621322298101726107\
05961164562990981629055520852479035240602017279974717534277759277862\
56194320827505131218156285512224809394712341451702237358057727861600\
86883829523045926478780178899219902707769038953219681986151437803149\

.
.
.

51205498805479514967289154302996769121988102263194659806380466107909\
31352857957674862371564191289402092625063920284548765631670222354467\
62108166903411674733689654891698040997088225756846422806485457083181\
54817250273792269673672784912715565863640224840546063168807939806419\
10011292989778642634722933479751500991951991756672702399802377950118\
74531421414112149235697793062845603141116573053057593276429408709647\
92714973972713169819730050190640877760201932333501404222064855249240\
36963502091099895258774893289262893136069071641672363453659300940411\
52727279580441683058589433882835637617510166237834248102913501606884\
97828073566475942021829737743512519707760133872287874153226344

real 199m59.237s
user 199m58.984s
sys 0m0.024s

/home/eldonb
Dogee$

-

-- Home Page: https://WA0UWH.blogspot.com

My Favorite Irrational Number

I have always been interested in numbers, especially special numbers like Pi (3.1415. . . ).

Normal whole numbers, like 1, 2, 3, etc (and their negative counter parts) are amazing when you consider there is no end to how far you can go to find a larger number, just by adding one. Within that very large range of numbers, there are many numbers which have their own special properties, for example the "Prime Numbers". As with all whole numbers, there is no Largest Prime Number, there is always a larger one to be found.

The whole numbers (plus/minus) and fractions that can be written using them are known a "Rational Numbers" - meaning that they can be written as a ratio (a fraction), for example:  1/1, 1/2, 1/3, etc.

But there is another class of numbers that can NOT be written as a ratio of two whole numbers, they are called "Irrational Numbers", for example the value of "Pi".  Pi can be written with many-many non-repeating digits without end, but Pi could never be written as an exact fraction (a ratio) of two whole numbers. There are many such "Irrational Numbers", many are used in science and found in Nature.

My favorite Irrational Number can be computed as simple as: (1+sqrt(5))/2

This can be computed with as many digits that you like with a simple Unix command (change that scale as desired for the number of digits):

        echo "scale=1000; (1+sqrt(5))/2" | bc

This is a very special number known as "phi".

A very interesting property of phi is:  1/phi = phi-1

No other number has this simple property.

Phi is found in many places in Nature, for example it is the way seeds are arranged withing a Sun Flower, the size of chambers of the Nautilus fish,  etc.

Phi is the name given to what is also called the "Golden Ratio" or "Golden Rectangle".

Here are the first 1000 digits of Phi:

1.618033988749894848204586834365638117720309179805762862135448622705
26046281890244970720720418939113748475408807538689175212663386222353
69317931800607667263544333890865959395829056383226613199282902678806
75208766892501711696207032221043216269548626296313614438149758701220
34080588795445474924618569536486444924104432077134494704956584678850
98743394422125448770664780915884607499887124007652170575179788341662
56249407589069704000281210427621771117778053153171410117046665991466
97987317613560067087480710131795236894275219484353056783002287856997
82977834784587822891109762500302696156170025046433824377648610283831
26833037242926752631165339247316711121158818638513316203840052221657
91286675294654906811317159934323597349498509040947621322298101726107
05961164562990981629055520852479035240602017279974717534277759277862
56194320827505131218156285512224809394712341451702237358057727861600
86883829523045926478780178899219902707769038953219681986151437803149
97411069260886742962267575605231727775203536139362



-- Home Page: https://WA0UWH.blogspot.com

Hands Free Jig

UPDATED:
Added Details and Links


In the past I successfully have used "Hands Free Soldering Jigs", but I wanted more functionality.

I found on ebay Machinist Magnetic Indicator Dial Gauge Holders, with a little 3D Printer Designed Adaptor they could be used as a Hands Free Soldering Jig.

A single Knob adjust and locks all three major joints.

In this case, the yellow alligator clip adapter was 3D Printed.

Also, another adapter (black) was printed, and a "Hat Pin" heated and inserted. This makes for a very nice PCB probe, an Oscilloscope probe can be attached to the top of the pin.

Once adjusted, these Dial Indicator Holders are "Rock Solid", once positioned they stay put, allowing for precise probing.  I use tape to hold board under test to the bench (thanks, Jeff - KO7M).

If used, the Magnet Base needs a stable steel attachment point, in my case, my bench edge is metal and provides as necessary.   The Magnet Base could be abandoned for something that could be attached to a wooden bench.

-- Home Page: https://WA0UWH.blogspot.com

Test Lead Rack - For my eShop

In my Electronics Shop, space and organization is always a challenge.  The following 3D Printed Test Lead Rack will help.

An Interactive Link To The Design

I designed the Test Lead Rack with Fusion 360 as one of my efforts to learn this new (to me) software.  I had been using Sketchup for most of my previous projects, but the lure of Parametric Design is to great to NOT switch to Fusion 360.  Also, a lot of public available designed parts are available from Fusion 360.

Now 6.5 hours later after design, the 3D Printer provides the Results:

And now, it is in use:

-- Home Page: https://WA0UWH.blogspot.com

3D Printer - MY Noob Mistakes

As posted before, I have been playing with a new TEVO Little Monster 3D Printer, I have made a LOT of Noob mistakes that could have been avoided if I had only knew.

The following are notes to myself.

o. Do not turn off the power to the 3D Printer unless you are certain that the Hot-End has cooled down. if not, removing power to the 3D Printer will cause the filament to melt within the Cold-End and then a complicated repair method will be required to fix the problem.

o. Remember, 3D Printing is very SLOW, it is much slower than waiting for paint to dry.

o. Remember the hot-end is VERY HOT, I have several burns to remind me.

o. Learn how to set the Z zero Height to within a paper thickness of the print bed, or nothing will work correctly until you do, no mater how hard you try.

o. Buy several sets of Print Head replacement parts, for the; Cold-End, Thermal Break, and Hot-End.

o. Consider buying some Tetrahydrofuran (THF) , it is the only effective thing that will dissolve PLA (for Hot-End  clean and repair), and it can be used to glue PLA parts together. Or at least that is what google suggests.

o. Note, MOST often Hot-End repair work will be done while it is HOT (about 210 C, or more), other wise PLA will be hard and not easily removed.

o. For my use, Blue Painter Tape works best for the Printer Bed, it has some texture that will show up on the printed part, but PLA stick very good to it. A roles of Blue Painters Tape (10 inches wide) are available on-line for about $50, and worth every penny, it makes bed prep very easy.

o. If the Hot-End is disassembled, for cleaning or repair, remember it has to be re-assembled and tightened while at intended operating temperature, for me that is about 215C.  If not, it WILL leak.


Note: I will add to this list as I learn more.


-- Home Page: https://WA0UWH.blogspot.com

Reduction Gears

Sorry, this is not an Amateur Radio post.

After many months of working with a 3D Printer, I have finally successfully created a working set of interlocking reduction gears, each section provides a 7:1 reduction. This device is about 2 inches in diameter, the total reduction is 14:1.

The original Ring Gear from Thingiverse was modified to create this multi-stage Reduction Gear. My contribution was to modify it as necessary and join two sets together.

Sketchup Model

The transfer plates (with the connecting pins) were assembled by adding the center HEX pin after printing.  Each of the two Reduction Cluster were printer as an assembled single object on the printer. No cleanup or filing was necessary.

Silicon grease is used for lube.

I may increase the size (and with other modification) this could be used as a Light Weight Field Day Antenna Rotor.

-- Home Page: https://WA0UWH.blogspot.com

Lost Friends

This week has not been a good week, very sad, two of my Ham Radio Friends have passed away.

Doug Phillips - W7RDP  (SK) a good friend from the local Pacific QRP Group (pQRP).

Don Sehulster - K7QYP / W7LSC  (SK) - a very good Navy Buddy (1968-1972).


73 - My Friends . . .  K



-- Home Page: https://WA0UWH.blogspot.com

First 3D Printer

I purchased a 3D Printer, and just now learning how to use it, there is a lot to learn.

After many trials and failures, I have successfully printed the equivalent of "Hello World" for 3D Printers, which is the "3DBenchy". This online part was designed to be a torture test for a 3D Printer, with many under-cuts, over-hangs and fills, that are somewhat difficult. This part is about 2.5 inches long.

My Printed 3DBenchy Results

3DBenchy was actually about my 10th attempt at print anything, the first few parts went horribly wrong.

Here are a few of my initial prints of a part of my own design, obviously I did not know what I was doing.

Things got better with practice and understanding of the 3D Print process and control parameters.

The above is a replacement part for an Orbital Sander, this part is no longer available from the manufacture, it will eventually be printed with Black ABS Plastic, which is similar to the original. I designed this part with FreeCAD and used Slic3r for the G-Code output for the 3D Printer.  For me, FreeCAD has a steep learning curve.


And, then . . .

On the next part, a Cable Chain of my own design, I must have lost the magic !!

But finally, things got better with practice.

Cable Chain Links

The First Two Links of a Cable Chain.

I am currently printing four Cable Links with newer/better design, I will report the results. For these link design, I have used Sketchup and Slic3r. For simple designs Sketchup is easy to use, as long as you only need "Union" style of object creation, that is, objects that touch are automatically joined together (union'd) when exported as an STL file. STL files are needed by Slic3r.

Four Cable Chain Links
About 2/3 Complete

This is fun, I think I am going to enjoy my new 3D Printer.


-- Home Page: https://WA0UWH.blogspot.com

Esp8266 WebServer Farm - Again

After several long months, I have reactivated my Esp8266 WebServer Farm.

Use this links to all of my Esp8366 project blog posts.

Esp8266 WebServer Farm

Currently, one of my WebServers can be accessed as: http://esp.wa0uwh.com:8154

The main reason that it has be off-line, is lack of interest, and recently, I could only get the code to compile on the old Arduino IDE (Rev 1.6.x).  The code is quite large and I took advantage of many "tabs" for code fragments, which are concatenated before presented to the compiler.  The new Arduino IDE Revision (1.8.1) is much more strict regarding Header Files, code files, and program structure. There were just TOO MANY errors to correct to keep my interest in solving the problem.

Once started to solve the problems and not getting much accomplished, my Friend Jeff - Ko7m, suggest another IDE, he suggested "PlatformIO IDE".

With little work, I found and installed PlatformIO, but alas, I found similar problems and concerns with it.  But little-by-little after much on-line reading, Jeff and I worked out the best file structures that worked with PlatformIO.

I have not moved the new code structure to GitHub, but maybe soon.


-- Home Page: https://WA0UWH.blogspot.com

My Soldering TIP #1

Several years ago my trusty Weller Soldering Iron failed, knowing that most of my projects were going to use small SMD parts, I ordered a fancy replacement, a Hakko FX-888 Soldering Station (about $90.00) with several assorted tips, some really small tips for SMDs. The tracking information, revealed that it would be in my hands in about three weeks.

But, I needed a replacement Iron NOW, to finish a project. I went to Frys, and found a cheapy Iron that I thought I could use (about $29.00), it was a Hakko Presto 980-V12/P. It had only one smallish chisel tip, but I thought it could be used for some larger SMDs.

Well, now several years later, the expensive Hakko FX-888 with its small tips is VERY seldom used (maybe about 3%), while the cheap Hakko Presto 980-V12/P is used for most (if not all) of my projects, and I am still using the original TIP. If you have seen my projects (typically on a 0.5in x 0.7in PCB boards) you might think the FX-888 would be more appropriate, but I fould it is not.

The following are some of my projects where the Hakko Presto 980-V12/P was used:

HomeBrew Double Sided
Si570 Board

HomeBrew Double Sided Project
These are 0805 Caps, and SOT-223 Voltage Reg

I like and use the Hakko 980-V12/P, it has "Two Temps, 20W normal, and 130W push button switch", very seldom have I used the 130W button.

I have recently purchased a second Hakko 980-V12/P for my tool box.

Today I think the Hakko 980-V12/P is priced about $60.00, if you are interested in online purchase, google is your friend. see: https://www.google.com/search?q=hakko+980

I think you will like it.

BTW: I use a "wall outlet timer" to supply power to my soldering irons, if I forget, the timer turns off power to them after about 45 minutes, which saves the soldering TIPs.

-- Home Page: https://WA0UWH.blogspot.com

A Small Experimental Receiver Circuit

I have finally found some time to "melt some solder" at my new location and new eShop bench. The bench is not finished yet, but I needed a Solder FIX.

This, like all of my project, is an attempt to make projects as small as my abilities allow.

New eShop Bench

The project that I am working on is some boards I just received back from OSH Park. The boards are a small and part of an experimental HF Receiver. The boards edge connectors are "Castellated" to allow them to be used within a larger PCB circuit, and with attached Headers, they can be used with/on a Solderless Proto Board.

The size of these boards are:
Left: 0.8x1.0 inch,
Right: 0.5x1.0 inch

This is my experimental design, it is a circuit that contain the:  HF VFO Mixer, Band Pass Filter (BPF, 40MHz), and BFO Mixer.

The bigger boards on the left are similar to those on the right, except they also contains the Oscillators for both the VFO and the BFO, along with the voltage regulator for the oscillator chip.

The components on the lower half are installed
Ready for some testing
Unpopulated is the VFO/BFO and Voltage Regulator

LTSpice suggests this circuit will work, but assessing the actual performance is the real reason for building this experimental circuit.

Additional circuits will be needed, to make this a real receiver, like: Band Select Filters, Automatic Gain Control, Audio Circuit, a Microcontroller, and Display. Likewise, I will make each as small as I can.

Testing will start when I have some (more) time.


-- Home Page: https://WA0UWH.blogspot.com

My new eShop

UPDATED: 11/21/2016

I have NOT posted anything for several (6) months, my life has been in somewhat of turmoil (maybe, I am getting too old for this), but now, maybe things are starting to get back to normal.

Regardless, I have been thinking of many HomeBrew projects that I want to build and blog. But first I have to set up my eShop in this new (and better) location.

This is the beginnings of my new eShop setup:

My new eShop Bench

I just finished building the wooden shelves. My previous eShop shelves were about the same but fixed, these shelves are movable, and therefore this setup should be more effective for varying sized electronic equipment.

Adjacent to that,  is my current MS 10 WorkStation, Raspberry Pi, and Orange Pi set ups:

Computer Workstation

The three bottom screens are connected to the MS WorkStation, and the three uppers are for the PI's.

Note: and the refrigerator is only about 15 feet away, hihi.

Unfortunately, I have not started my Ham Station and Antenna System yet.

I have some small Ham Radio related PC boards out for manufacturing at OSH Park, if they works as expected, I may be blogging about those, soon.

UPDATE:

The day after installing my shelves and turning on the Oscope for the first time in a long while, the (calibration) trace is going bonkers, with a short bright spot at the beginning of the trace. Trace INTEN has little control.  DANG, now something else to repair.
-

FORD Rant - Oil Cooler Bypass Valve - is a non replaceable part.

UPDATED: Tue May 17 11:19:46 PDT 2016

This is post not about Electronics, it is a RANT about FORD.

For the last few weeks, my Son and I have been working on his F350 6.0L Diesel Engine, to replace; the Exhaust Gas Recirculation (EGR) Heat Exchanger, and the Oil Cooler. This work is a pain because most of the top of the engine, including the Turbo Charger has to be removed to get to the parts being replaced. There are several good Youtube video showing the details.

We ordered parts and gaskets bases on information available. This repair is somewhat of a difficult task due to engine compartment large size and the long reaches necessary to access everything.  There is one very dirty mess when the Oil Cooler cover is removed, where about a quart of oil spills over the engine valley, but that cleanup marked the beginning of the actual part replacement and rebuild.

Most of the previously dis-assembled parts where replaced in the order they were removed without difficulty.

But Then

FORD Failed
Oil Drain Back and Oil Cooler Bypass Valve Assemble

On top of the Oil Cooler Cover there is a small assemble which is held in place with two screws within the Oil Filter Case (Can). This small assemble is about 3 inches wide.

This small assemble holds two valves; one to Drain Back oil from the Oil Filter Case (helpful during oil and filter changes), and the other is the Oil Cooler Bypass Value (OCBV) which opens in case the Oil Cooler get clogged up. These two valves are very simple; the first is held shut by gravity and can pressure; the other is a spring loaded Brass Plunger with a small flat plastic/rubber (of some sort) washer (flapper) that opens at 25lbs of Oil Cooler pressure.

Spring Loaded Oil Cooler Bypass Value
The Brass Plunger shows scoring

The Wood Chip holds open the washer at the failure.

The Problem

According to FORD, these two small values are NOT replaceable parts !!

And therefore, normal Auto Parts stores do not have the parts, nor does FORD.

Our OCBV plastic/rubber seal is damaged, and the Brass Plunger is scored showing that it had failed long ago.

The values can only be replaced with a NEW Oil Cooler Cover, which is about $180.00, the plastic/rubber part, if available, should only cost about $2.00, even though it is about $0.10 worth of plastic/rubber.

My Conjecture

I suspect that the OCBV failure contributed to the EGR Cooler failure and therefore the need to repair this engine - it is a $0.10 part ?

Our Planned Fix

Google searches provided very little help or suggestions of a solution.

Our current plan is to create a new Teflon washer (value flapper). A Teflon rod is now on order. Experiments with different on-hand materials failed to hold up in a gas/oil environment.  Teflon appears to have the right properties; inert and high temperature resistant.

Thanks FORD, my Son's truck has be on blocks for about three weeks now, while finding a workable solution.

End Rant

If this works as planned, I will be selling Teflon washer, and or Teflon Plunger with integrated Teflon Value seat, . . . soon :-).

Teflon Washer

Update:
The engine has now been running with the new Teflon Value Seat for several weeks, when the oil is changed it will be removed and inspected for ware.

Here is a photo of the Bypass Valve Assembly reinstalled ( I had forgotten I took this photo). The Oil Filter Tower and Canister have not been reinstall yet, as can be seen, two screws hold the assembly in place. Inspection for ware at the next oil change, will be easy.


-

-- Home Page: https://WA0UWH.blogspot.com

ASCII Strings within the Largest Known Prime Number

Someone on the Youtube Numberphile Channel was wondering if after converting the Largest Prime Number  to base 26 (see previous post) would there be any interesting ASCII strings within the Number.

I think I have created a Unix Function that will do the conversion.

( echo "obase=16;"; echo "obase=26; 2^74207281-1" | bc | tr -d '\n\\' | sed 's/ /;65+/g' ) | bc | xxd -r -p

This will take a while (maybe several hours, or days), but if I find something interesting, I will report the results.


-- Home Page: https://WA0UWH.blogspot.com

The New Largest Prime Number Found

UPDATED:
Added Details and Links

Recently (Jan 7. 2016) the next and Largest Prime Number has be found (so far), it has about 22 Million Digits long, See, YouTube at: https://goo.gl/C7ngE7.

The number can be expressed as a small-simple math function, that is: "2^74207281-1"

The previous Large Prime Number (17 Million Digits) was found about 3 years ago on Jan 25, 2013, see: http://goo.gl/UbAWK0

Hopefully, and if history hold true, we will see the next Largest Prime sometime within the next 3 to 5 years.

Just for fun, I decided to see how long it would take my 3.4GHz Workstation to perform the calculation and print the full 22 Million Digits to the screen - it took about 154 minutes - it was like watching paint dry.  :-)

Note: To verify that it "is actually prime" would probably take several months (or more actually several years) on my computer.

Here is the linux command that I used to print this New Prime, and a few of the Beginning and Ending Digits of the results:

$ time echo "2^74207281-1" | bc
30037641808460618205298609835916605005687586303030148484394169334554
77232190679942968936553007726883204482148823994267278352907009048364
32218015348199652241372287684310213386284573666361506667532122772859
35986405778025687564779586583214205117110963584426293657265038724071

.
 .  ( 22 Million More Digits )
  .

74801792765597096176486305356033886997788467889060830923906229428002
87770846681535011427622921221836904045477963931367013401448014940470
41169663347456468851607177740147629124621136468794258014451073931002
12927181629335931494239018213879217671164956287190498687010073391086
436351

real 153m50.931s
user 92m34.588s
sys 0m13.496s

Note: To capture the number on the screen, a large display buffer of more than 22 Meg Bytes (of RAM) was necessary.

I need to check with YouTube and/or Numberphile to see if my calculated number is correct  :-)

My computer is current checking four large numbers to see if they are Prime, this consumes about 100% of the Quad Core CPU, but it runs at a very low priority so it does not effect my use of the computer. Each is expected to finish at different times, Below shows the number being tested, and number of days until I should have the results:

• 2^332,338,003-1, results expected in 643 days
• 2^332,338,319-1, results expected in 643 days
• 2^332,338,397-1, results expected in 858days
• 2^332,338,777-1, results expected in 858 days

As you may have expected, . . . I am a fan of Very Large Numbers !

-- Home Page: https://WA0UWH.blogspot.com

Simple Complexity - By Proxy

UPDATED:
Added Details and Links

For sometime I have struggled with how to allow public access to my home web servers and Esp8266 modules without opening up my network to abuse. In the past I have managed public access via my Router, by changing its configuration of Port Forwarding and NAT.  This works, but it is a pain to manage and generally requiring a re-boot of the network for each change.

Recently, I have discovered (actually re-discovered) that an Apache2 Web Proxy Server is much easier to manage, but it has a bit of a steep learning curve, with a lot of manual pages to read. One key concept is that Apache2 ReWriteRules are a super-set of the functionality of ProxyPass, each have their own documentation web pages.

After building the Required Config files

Now, on my Router I allow only Ports: http 80, 8040, 8160, and a private ssh port for access from the Internet. Ports 8040, and 8160 are still open for historical reasons, that is, they are used for my published Web Pages at: http://www.WA0UWH.com:8040, and my Esp8266 Server Farm devices.

The Apache2 Web Server supports: Virtual Host Names with Proxy Redirects, ReWriteRules, and ProxPass. By setting up "*.wa0uwh.com" as a CNAME (an aliases) to "www.wa0uwh.com" at my DNS Provider, I can use any "device name" I would like in the config files to initiate a proxy process. For example: I can now use and publish "http://node129.wa0uwh.com" for one of my Esp8266 Web Server modules. The actual connection details and security are all hidden behind the proxy curtains.

The normal web page port 80 is setup with a default virtual host page of; "Error 404", only configured virtual hosts and named devices are let through the proxy.

Note: The service and/or host that is selected is a combination of both Port Number and Host Name (or alias). For an incoming connection, the file is scanned from top to bottom, only the first match is used to select the service.

The following are excerpts from my Apache2 Default Virtual Host configuration file.

ServerName default.wa0uwh.com
LogLevel alert rewrite:trace1

<VirtualHost *:80>

    ServerAdmin webmaster@localhost
    DocumentRoot /var/www/DEFAULT/Public

    ErrorLog ${APACHE_LOG_DIR}/error.log
    CustomLog ${APACHE_LOG_DIR}/access.log combined

</VirtualHost>

# End

The following are excerpts from my Apache2 Named Virtual Host configuration file.

## Main Web Pages

## Loft Raspberry PI
<VirtualHost *:8040 *:80 >

    ServerName  rp21.wa0uwh.com
        RewriteEngine on
        ServerSignature Off
        RewriteRule /(.*)$      http://192.168.___.___/$1 [P,L]

</VirtualHost

## Loft Raspberry PI
<VirtualHost *:8040 *:80 >

    ServerName  rp22.wa0uwh.com
        RewriteEngine on
        ServerSignature Off
        RewriteRule /(.*)$      http://192.168.___.___/$1 [P,L]

</VirtualHost>

# Esp8266 Node on Published Port 8160
<VirtualHost *:8160 >

    ServerName  node.wa0uwh.com
    ServerAlias node*.wa0uwh.*
    ServerAlias localhost
        RewriteEngine on
        RewriteRule /(.*)$    http://192.168.___.___/$1 [P,L]

</VirtualHost>

## Loft Esp8266 Nodes
<VirtualHost *:8040 *:80 >

    ServerName  node.wa0uwh.com
    ServerAlias node*.wa0uwh.com
        RewriteEngine on
        ServerSignature Off
        RewriteCond %{HTTP_HOST} ^node(129|162|164|168|169|170|172)\.wa0uwh\.com [NC]
        RewriteRule /(.*)$      http://192.168.___.%1/$1 [P,L]
        RewriteRule /(.*)$ -  [R=404,L]

</VirtualHost>


## Loft WA0UWH Web Server
<VirtualHost *:8040 *:80>

    ServerName www.wa0uwh.com
    ServerAlias *.wa0uwh.com
    ServerAlias localhost 192.168.__.__ 
        DocumentRoot    /var/www/WA0UWH/Public
        Alias /gallery  /var/www/WA0UWH/Public/Gallery

</VirtualHost>

# End

Note, the above is just an excerpt from my Apache2 Virtual Host config file. For security reasons, the details; actual IPA's (___), BlackListing, Hacker Traps, Web Abuse Traps, and HoneyPots, are NOT included . Google is your friend for suggested configurations.

Now, with simple edits of the Apache2 Virtual Host config file, I can turn ON or OFF, devices and/or services as desired, while leaving only the http and ssh ports open for public access at the router.

Also note: each of my Raspberry PI Web Servers also have similar Apache2 Virtual Host config files, that is: Proxies are serving Proxies, and most often the actual destination is at different physical locations, and on different Networks! All unseen for my Internet users.


-- Home Page: https://WA0UWH.blogspot.com