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That sounds simplest, so far. 
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It is my task in life to find the simple way to do things! Engineers are essance lazy, they find generally find a simple cheap way of doing things, managment complicate 
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If you plan the clock for the Central European market, you are within the coverage of DCF77[^] - it reaches half way up Norway.
The DFC77 signals, at 77.5 kHz (really longwave!) are so primitive, both at the physical modulation level and the data format, that I often refer to them as 'Morse code Mark II'. The frequency is so low that you could probably sample the signal from the antenna directly (after a simple tuning circuit) using any standard microprocessor that can take an analog input.
(My PC sound card is capable of producing 192 kHz sample rate sound, sufficient for generating the right on-the-air waveforms. I have jokingly suggested that once I get myself a new stereo amp capable of handling analog 192 kHz, I will plug an antenna into the speaker connectors and have my PC generate DCF77 signals to adjust all the DCF77 clocks in my neighborhood by an hour or two .)
The DCF77 data gives you exact time and date directly in binary format. The simpler way to do it is to feed these digital values directly to a numeric LED display. If you very much want an analog clock, you would use a stepper motor (moving arms 6 degrees/pulse) that at reset moves the arms to 00:00:00, and then moves each arm as many steps as the digital time value indicates. After a power down, you would have to do a reset (which may cause each arm to move all the way around - in theory almost twice: One to go from 1 to 00, and then from 00 to 59, if the arms were at 01:01:01 and the correct time is 11:59:59), but you need not worry about anything else to keep it in sync.
If you have battery backup for the stepper motors and the (very simple) electronics - it is as if the smallest Arduino is overkill - the clock doesn't have to stop, unless you want it to. One of my DCF77 clocks says in the documentation that to save battery power, it turns on the receiver once an hour checking for drifts of the internal oscillator, possibly holding back one pulse or giving one extra to the seconds arm, but even the cheapest oscillators nowadays are so stable that hourly check is probably overkill. You can just turn off the receiver completely if external power goes out.
I haven't been using a soldering iron for years, so I never build a DCF77 clock like this (but I have come as far as to buy the stepper motors for it ) - I guess you know how to handle the electronics much better than I can. Now that you post at CP, I take it that you also handle the software part well .
ps. If you do this, write a CP article about it!
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 Never even considered that. Even though I'm old and am used to things like LORAN-C (we used it just for the pulses, not positioning).
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You might be able to use an Arduino or better yet, an ESP32 to control the steppers on the thing
An IoT Smart Clock Using an ESP32 Development Board[^]
IoT Smart Clock using the Mega 2560+WiFi R3[^]
These clocks use WiFi and NTP rather than a radio based sync mechanism so they don't support time zones but could be made to be configurable or modified to use the radio system.
Anyway, some of the principles therein might be useful. Get an ESP32 as they are cheaper and more capable than arduinos + smaller. I included both for the sake of completeness although the arduino one uses an ESP8266 as it's primary worker CPU, not the ATmega2560
Real programmers use butterflies
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Thank you. More things to read about.
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[^]555 is also 'yer friend ...
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Going from simple to complex:
Asynchronous motors with a good reduction and an external encoder can work.
Steppers will do it if you don't need much torque and you don't need them to rotate fast (they can loose position feedback if they turn too fast) (you would need an external encoder to prevent that).
Servomotors will give you a bigger range of speeds and torque while not suffering from the loss of precision at fast speeds.
![Beer | [beer]](https://www.codeproject.com/script/Forums/Images/beer.gif)
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The last paragraph of that is pretty good and it's about twenty years old now.
"They have a consciousness, they have a life, they have a soul! Damn you! Let the rabbits wear glasses! Save our brothers! Can I get an amen?"
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Interesting that you post this since I was going to suggest, to your previous thread about perf, that you dip down into ASM to wring out some speed.
And here you are.
(I've always admire those fluent in any dialect of ASM, but have never actually bothered trying to learn a single instruction. Maybe about time I just spent a weekend diving in)
cheers
Chris Maunder
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I haven't even started to use that yet, because I'm trying the portable strpbrk() function over a memory mapped file first.
My results are fire.
Approx stack size of local JSON stuff is 176 bytes
Read 1290495 nodes and 20383269 characters in 249.894000 ms at 76.032238MB/s
Skipped 1290495 nodes and 20383268 characters in 33.278000 ms at 570.947773MB/s
utf8 scanned 20383269 characters in 75.141000 ms at 252.857960MB/s
raw ascii i/o 20383269 characters in 58.162000 ms at 326.673773MB/s
raw ascii block i/o 19 blocks in 3.130000 ms at 6070.287540MB/s
Bold line is where I search fast through a document
Edit: Fixed a fencepost error in counting the position.
Edit 2: More complete benchmarks:
Query is $.season[7].episode[2].overview
Approx stack size of local JSON stuff is 152 bytes
Found "Labore magna sint occaecat ea officia labore sit voluptate ut fugiat. Nisi qui commodo consectetur officia incididunt anim do culpa eu. Eu ea magna aliqua excepteur et. Qui eiusmod irure adipisicing enim aute nostrud deserunt eiusmod quis culpa id.rn" and scanned 7149420 characters in 12.034000 ms at 498.587336MB/s
Query is $..id:
Approx stack size of local JSON stuff is 152 bytes
Found 40008 fields and scanned 20383269 characters in 65.563000 ms at 289.797599MB/s
Approx stack size of local JSON stuff is 176 bytes
Read 1290495 nodes and 20383269 characters in 256.696000 ms at 74.017515MB/s
Skipped 1290495 nodes and 20383269 characters in 33.527000 ms at 566.707430MB/s
utf8 scanned 20383269 characters in 72.913000 ms at 260.584532MB/s
raw ascii i/o 20383269 characters in 57.787000 ms at 328.793673MB/s
raw ascii block i/o 19 blocks in 3.106000 ms at 6117.192531MB/s
Edit: Found and fixed a bug with some escape characters not getting translated. (regression when I introduced my fast scanning)
Real programmers use butterflies
modified 27-Dec-20 22:19pm.
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Too high level. Anyone remember:
C:\>debug
-D
0B06:0100 75 60 C6 46 00 00 8A 7E-04 F6 C7 04 74 E6 C6 46 u`.F...~....t..F
0B06:0110 00 02 8B 76 02 80 3C 00-74 4B B3 2E 34 00 F5 0A ...v..<.tK..4...
0B06:0120 B3 3A 38 5C FE 74 05 C6-46 00 01 4E 32 DB 86 1C .:8\.t..F..N2...
0B06:0130 E8 39 EB 3B D6 73 1B 56-51 8B CE 8B F2 AC E8 B2 .9.;.s.VQ.......
0B06:0140 E1 74 09 AC 3B F1 72 F5-59 5E EB 0B 3B F1 72 ED .t..;.r.Y^..;.r.
0B06:0150 59 5E 3A 5C FF 74 0E B4-3B CD 21 86 1C 73 95 E8 Y^:\.t..;.!..s..
0B06:0160 9B DA E9 C9 D7 E9 C3 D7-89 7E 02 80 46 01 0C B8 .........~..F...
0B06:0170 3F 2E B9 08 00 F3 AA 86-C4 AA 86 C4 B1 03 F3 AA ?...............
-
Now, those were the (so-called) good old days. :)
If you can keep your head while those about you are losing theirs, perhaps you don't understand the situation.
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Yes. That reminds me of when i learned 6502 bytecode before i realized i had a built in mini-assembler.
Real programmers use butterflies
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The first assembler I used was simply adding symbols. The instruction set was very regular (the CPU architecture from the days long before microcode), so opcode, modifiers and offsets all had their fixed place in the instruction word.
We played around with this: To generate a MUL (multiply) instruction, you could rather use ADD ADD, as the opcode for MUL was twice the opcode of ADD
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If you consider one weekend enough...
Wrong is evil and must be defeated. - Jeff Ello
Never stop dreaming - Freddie Kruger
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Chris Maunder wrote: but have never actually bothered trying to learn a single instruction.
Allow me to get you started:
MOV Chris, Good_Book;
JMP ASM_PRO;
| Ravings en masse^ |
|---|
| "The difference between genius and stupidity is that genius has its limits." - Albert Einstein | | "If you are searching for perfection in others, then you seek disappointment. If you seek perfection in yourself, then you will find failure." - Balboos HaGadol Mar 2010 |
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I have a short attention span.
Does it contain pictures and large fonts?
cheers
Chris Maunder
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Does what?
| Ravings en masse^ |
|---|
| "The difference between genius and stupidity is that genius has its limits." - Albert Einstein | | "If you are searching for perfection in others, then you seek disappointment. If you seek perfection in yourself, then you will find failure." - Balboos HaGadol Mar 2010 |
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That is pretty interesting stuff! I used to be a fractal fanatic and spent a lot of time optimizing algorithms and investigating alternatives. Then I came across GPUs and CUDA and the search was over.
"They have a consciousness, they have a life, they have a soul! Damn you! Let the rabbits wear glasses! Save our brothers! Can I get an amen?"
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You need to check out FRACTINT[^] - more fractal than even a fanatical fanatic can handle. It just seems to have more and more features. The Wikipedia link hardly touches the surface.
| Ravings en masse^ |
|---|
| "The difference between genius and stupidity is that genius has its limits." - Albert Einstein | | "If you are searching for perfection in others, then you seek disappointment. If you seek perfection in yourself, then you will find failure." - Balboos HaGadol Mar 2010 |
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Yes, I have it and it is quite good. I got lots of ideas from it.
For the highest performing fractal program I have ever seen - check out the Mandelbrot sample that comes with the CUDA SDK. It calculates in real time. You can pan and zoom and updates are instantaneous. It is really fast.
"They have a consciousness, they have a life, they have a soul! Damn you! Let the rabbits wear glasses! Save our brothers! Can I get an amen?"
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SSE 4.2 is overrated though. The instructions are neat, but they don't execute very quickly. There are also no AVX2 equivalents, just a VEX-encoded version of the 128bit operations. Overall, SSE 4.2 usually doesn't work out that well, though it has niche uses, and it turns out that the PCMPEQB & PMOVMSKB combo wins. It's a bit more boring perhaps, but it turns out that just because something is made for a particular purpose, that doesn't make it the best for that purpose.
Glibc also uses generic instructions instead of the SSE 4.2 special stuff.
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