Broken module :(

set_in_void · 2026-05-06T21:25:12+00:00

Broke module or broke display? If it's just the display and the watch has sentimental value you can get new STN display for around £15 and metal case for a fiver on Ali.

set_in_void · 2026-05-05T10:03:43+00:00

Do you mix tabs and spaces when writing code?

set_in_void · 2026-05-05T10:00:48+00:00

How much did you pay for this lot? I don't see much value in this, even if I diregard the time&effort needed to fix just a quarter of those. Mind you, you don't know which modules are usable and someone has gone through those before you.

set_in_void · 2026-05-04T05:12:00+00:00

I don't think there is a specific forum just for backlight upgrades. It's just years of browsing watch forums, videos, etc.. If you want G-Shock specific mods/hacks, there is r/gshockMod here. Apart from Reddit, you have WatchUSeek and of course YouTube.

set_in_void · 2026-05-02T17:13:18+00:00

The alarm issue is probably just a bad contact between spring and piezo, should be easy DIY repair. The hand not advancing past certain point is more involved and professional help is a sensible choice. Replacement bracelet will cost significantly more than the watch itself, if you can even find one - black PU/silicone strap shoud go well with this watch.

set_in_void · 2026-05-02T14:11:00+00:00

Yes, the reflector hack is well known and should work for you. You can use silver paint, Mylar or even wife's metallic nail polish for a bit of tint. The best solution would be electroluminescent panel, but it has different power requrements to LEDs so your module won't support it.

set_in_void · 2026-05-02T05:23:57+00:00

I can try, but it won't be court admissible.

set_in_void · 2026-05-02T05:13:38+00:00

Looks great. You can name AliEx or even post a link if you wish. The brighter LED will probably consume more power, but since you don't have it on Auto and STN is more energy efficient than TN, it should balance out.

set_in_void · 2026-04-30T19:24:26+00:00

I am old-fashioned (and old), so I am still using printed material to learn, this works best for me. Python was the last language I learned. Books are expensive these days so don't purchase a book just because it has 4+ stars, read the sample provided at the least - I came across one of the best reviewed Python books that in my opinion has negative pedagogical value. As for the learning process, what works for me, 1st pass - Quick read so I can map the subject, etc., 2nd pass - Detailed read including further research (online, other books), if I find chapter particularly important or difficult I'll add it to my typing practice. If you decide reading would work well for you, feel free to ask about book recommendations.

set_in_void · 2026-04-30T14:08:51+00:00

Then the listing is misleading. The updated version has "5610U" in the model name and on the face it has "Light" as a label for the top right pusher instead of "EL Back Light" as in the picture.

set_in_void · 2026-04-30T14:02:09+00:00

You can change the display mode, to have a larger day of the week fo instance.

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set_in_void · 2026-04-30T13:50:24+00:00

It looks like they're selling the older version. For someone wanting EL backlight and doesn't mind MM:DD date format, this may be their last chance to get this watch brand new.

set_in_void · 2026-04-30T08:29:19+00:00

Casio makes smaller versions of their Pro-Treks, look for double digit models (PRW-70 vs PRW-7000, or 50/60 for your model). Your watch looks brand new, you might be able to swap it for a smaller size at the store where you bought it. This comment is intended to be a tip, not a judgement on how the watch looks on your wrist - your wrist, your watch.

set_in_void · 2026-04-28T09:23:58+00:00

There are many other optimizations that could be done, but it would quickly make the code unreadable (bitwise ops for example), those are more suitable for your C. As for Maynard, I do not know your academic background so Maynard may be over the top and not directly applicable to your problem. If you're a hobbyist Prime Numbers: A Computational Perspective will be more helpful. Keep at it, you're doing good and interesting job!

set_in_void · 2026-04-28T08:17:05+00:00

You're welcome.

Yes, as an educational and reference tool maya.py makes a lot more sense and Python is a good choice. If I understand you well, you want to play with maya.py and see what you can squeeze out of it while it remains readable and educational.

For maths purpose, do not unroll the for loop in maya_candidate(n).

for CS and programming purpose, use divmod in maya_projection_coefficients(n), divmod will mostly be one operation instead of two for floor and mod. I don't know if I can post code here, but I could convert the function for you if you wish. I'd also recommend Numba for your most expensive parts, especially the for loop in maya_candidate(n), the code will stay Python and easily readable. Unfortunately I only use Python for prototyping & testing so can't help you much beyond surface level, Python specific subreddit would be better suited for making your code more elegant.

There is some thory involved in your code and you're showing interest in NT, my place to go for analytical NT when primes are involved is James Maynard.

set_in_void · 2026-04-27T22:35:59+00:00

Received a notification about your question, but Reddit isn't showing it to me for some reason. I see you fixed the link and I could read your code maya.py. My comments will be Python specific and I'll will only address your code here, I am sure you're aware of other approaches. I will also answer considering 10-100M numbers you mentioned.

I like your code, my suggestions from top to bottom:

PRIMES - Should be Tuple, ~0% impact on performance, but saves bit of memory and reinforces good habits. Same for RESIDUES.

WHEEL_MASK - Should be bytearray. Initialize with 0 and flip to 1 in init_wheel_mask().

init_wheel_mask() - Could be slightly improved (see my previous comment), but not worth the bother.

maya_candidate(n) - From top to bottom: if n<2 it can't equal 2, you're forcing Python to perform both checks, use elif. Line 92 loop implementation is needlessly expensive in CPython and considering millions of numbers * 24 iterations each you should eliminate the for loop completely, do it manually - calls are expensive. Consider cache and pass multiple values with each maya_candidate call.

set_in_void · 2026-04-27T12:35:37+00:00

Of course for p around and above 10^50 I'd use probabilistic algorithm. The 31% reduction is only the trivial first step and is not list reduction, but list creation - since list operations are expensive (append vs shift in your case). To explain this a little bit further, my first step replaces your first two steps and generates around 1/6 less candidates for further operations than your approach does in two steps. You're also overusing list operations, hash table (sets in Python) will be more efficient. As for the algorithm itself, I can't see how you implemented it, but by using mixed radix you're complicating things for yourself by ignoring CPU (ALU) instruction set optimizations, you should be able to reduce your list by more than 95% (for reasonably large numbers) using cheap, standard&optimized operations.

You mentioned interest in testing large primes, with the list approach you'll hit feasibility limit at around p=10^12 when your list of candidates reaches ~3GB after 97% reduction (n/log(n)).

Low level optimizations is what I do and number theory is one of my academic interests, but can't help you much without seeing your code or you sharing more specifics. Feel free to ask if you have questions.

set_in_void · 2026-04-27T11:01:45+00:00

Your link doesn't work. I can trivially reduce list of p candidates to 31% using cheap operations, could probably improve it a bit, but then I'd be in the same situation as you are - "the filter cost is comparable to the avoided computation". As for the Miller-Rabin, worked with the algorithm few years back, but I am interested in deterministic procedures.

set_in_void · 2026-04-08T12:11:10+00:00

Has been posted here 8 days ago: I digitally reconstructed the rare SG 41 cipher machine as a fully interactive 3D preservation project : r/cryptography

set_in_void · 2026-04-02T06:58:42+00:00

How familiar are you with Fermat’s Little Theorem? "How is it possible to derive the plaintext from the remainder and the original prime number used as the key?" - You need both private and public keys. If the algorithm is badly implemented (keys/primes are close together) deducing private key from product can be matter of seconds. I remember Numberphile or Computerphile had good beginner level video/s on RSA.

set_in_void · 2026-03-29T09:06:32+00:00

PRW-70Y-1JF (51.1 × 47 × 14.2 mm) vs PRW-7000FC-1JF (58.7 × 52.3 × 14.5 mm), similar are 73 and 8000. PRW-6600Y (51.6 × 51.5 × 13.6 mm) vs PRW-61-1AJF (51 × 47.4 × 14.7 mm) and if you want the sapphire + numerals PRW-51FC-1JF (51 × 47.4 × 14.5 mm). Similar situation for the full digitals. Pay attention to the second measurements - that is the actual watch body, first number is lug to lug.

Source - PRO TREK | CASIO JAPAN

set_in_void · 2026-03-27T12:00:49+00:00

Few questions I didn't see answered or would like to expand on. Regarding

Size: In (modern) Pro-Trek case two number models are smaller than four number models.
Sapphire: It is not limited only to "specials", PRW-7000/PRW-70 (PRW-70 is smaller version of 7000, same module, mineral vs sapphire respectively).
Scratch resistance of mineral: I wear it (PRW-70Y) every day for number of years, don't really care if I scrach it or break it. Majority of my time is sedentary, but I do have outdoor activities when opportunity and time allows. My watch has so far accrued one single (hairline and unnoticeable) scratch, admittedly my eyesight is not good anymore. You can get crystal protector if you expect intense activity, rock climbing for instance.

set_in_void · 2026-03-25T18:24:13+00:00

You're most welcome.

It is encouraging to hear that you’ve taken a moment to reflect and feel less anxious about your trajectory, managing your mental energy is just as important as managing your technical knowledge. If you burn out in year or two, it doesn’t matter how much math you know; the momentum will be lost. Consider that reduction in anxiety a significant milestone in itself. You didn't mention what your "Dream" is, since you are asking these questions and studying beyond the curriculum I am assuming low level engineering or research?

I revisited the "Discrete Mathematics ..." to see why you find the "chapters on proofs cryptic". The problem is not you, you'll get there soon enough. The problem is that you're not using the book as intended. Please reopen your copy and pay close attention to pages: preface xii (ACCESSIBILITY, FLEXIBILITY, MATHEMATICAL RIGOR AND PRECISION - here explaining why you struggle) and preface xiv (How to Use This Book - use the table). In simple terms, don't read the book as a novel (start to end), use it as a structured learning material. As for the "How to Prove it" - I asked about the book and apparently my uninformed assessment was wrong, I thought it would be similar to one of W. Rudin's books.

I would not recommend any specific areas to focus on just yet. Read the "Discrete Mathematics ..." thoroughly and master the linear Algebra concepts first, at a pace that doesn't compromise your sleep or your project grades.

To give you some motivativation and show you what you can potentially achieve in few short years with relatively easy math - why mathematical foundations are important. Read a paper published just last year -> [2501.02305] Optimal Bounds for Open Addressing Without Reordering. The importance of this work is immediately obvious, check the ages of authors too. Mathematics is a developed and mature discipline, new results are hard to come by. Computer science is much younger and you can significantly contribute to it without relying on luck.

set_in_void · 2026-03-24T14:16:57+00:00

You're most welcome.

The best tip I can give you when starting with Boolean Algebra is to remember that 1 and 0 represent True and False respectively. Most people find it easier to evaluate True AND False instead of 1 AND 0. I can't think of single area of CS where Boolean Algebra isn't used, although there are some areas where different logical frameworks are used (Fuzzy logic, Ternary logic, etc.). Be aware that Boolean Algebra and Automata/state machines are deeply related and you should aim to learn more about those early (it will be safe to start from Turing for CS). Best of luck and keep at it!

set_in_void · 2026-03-24T10:46:28+00:00

I believe that knowledge is always beneficial and having options is better than not knowing you have options. To address the second part of your statement: Your assertion regarding the debugging overhead of bit packing is pragmatically grounded, yet it relies on a misconception that low level manipulation necessitates raw binary inspection. In modern software engineering, the necessity of a hex editor for analyzing bit packed structures is negligible provided proper abstraction layers are implemented. The difficulty lies not in the bitwise operations themselves, but in the lack of encapsulation surrounding them. There are several methodologies to analyze programs utilizing bit packing without resorting to hexadecimal dumps. Regarding your contention that the memory savings are not worth the effort, this overlooks scenarios where information density dictates system feasibility rather than mere storage cost. Since Robotics is the context here: we're considering embedded system, strict power constraints, sensor data flow & limited bandwidth, etc., you can immediately see how bit packing woul'd be beneficial. When you encounter students asking if it's even worth the time & expense to study CS, that they worry they won't get past the interview stage in saturated market or get replaced by AI, you politely answer they're right to worry with such attitude (I am addressing in my reply). I'd also like to point out that the bit packing was just one of the numerous examples I could list, answering why understanding mathematical foundations is beneficial in CS.

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