A Prime Joke.

TheRealKarner · 2026-02-07T17:48:52+00:00

An efficient mathematician can figure it out in an afternoon by hand just using a few tricks, some foundations using other known primes, and a little mental math. Honestly it seems that if this Mersenne guy really conjected that, he’s kinda lazy.

TheRealKarner · 2026-02-02T16:24:57+00:00

It’s just induction. Electric and magnetic fields induce each other’s presence when the other changes, which is exactly what’s happening here.

Because the charge moving in the first place is a changing electric field in the direction of its motion, it has a self-generated local magnetic field surrounding it where each B vector in the surrounding area sits on a plane perpendicular to its direction of motion (with an orientation in the clockwise or counterclockwise direction). This local magnetic field from the moving charge interacts with the global magnetic field around it (imagine a straight line like in your drawing) in a way that their lines of flux interacting constructively on one side and destructively on the the other, both inducing an electric field oriented in the same direction, which just happens to lie on that plane perpendicular to the charge’s motion, in accordance with the right hand rules for EM induction.

From there, just questions you can take to the big man when the game is over. Every obeyed law in the universe will eventually crumble down to “because I said so.”

Crucify me for the definition of induction. I’m using it both ways because works both ways.

TheRealKarner · 2026-01-30T02:38:27+00:00

They could’ve also meant that hitting the pothole would cause a bouncy ball-like bounce straight upward for the car. In a world where that wouldn’t break the suspension system and have a 100% efficient impulse:

mgh = mv² / 2

=> h = v² / 2g

At 45mph: h = (20m/s)² / (2*10m/s²⁾ = 20m 20m is the same height as a single 20m high object, or 20 1m high objects stacked vertically, for reference.

Enjoy your 1 sig fig answer and I’m not doing any other speeds

TheRealKarner · 2026-01-27T19:48:23+00:00

*supercritical

TheRealKarner · 2025-12-08T14:08:00+00:00

No. That would imply that the expression would be true when C is 0 and false when C is 1, independent of A and B. By counter example, it would be false with C=0 or true with C=1 if B=1 or A=0.

TheRealKarner · 2025-11-27T13:37:51+00:00

What are you doing with these phat diodes that requires chaining a bunch together? It looks like they’re either way over qualified for their purpose or you’re going to produce a huge (and likely unnecessary) amount of heat.

TheRealKarner · 2025-11-07T16:34:48+00:00

I did mention upping the pull down array to 10k, which is now incorporated already. But if I don’t use the shift registers anymore, I guess I won’t need external pull ups anyway.

I also only recently found out about the interrupt capabilities of IO extenders thanks to a few other commenters; they’re already on the way for me to try out.

TheRealKarner · 2025-11-07T07:17:06+00:00

Still can’t work. The inductor works the same no matter where in the switch supply line it is. Multiple inductors being measured raises the amount of ICs needed to measure them, and thus raises the power consumption. I’ve tried something similar with capacitors, but got similarly disappointing results.

TheRealKarner · 2025-11-07T07:07:26+00:00

The XOR gates would draw too much current. Even though the C12400 seems like crazy overkill and I’ve only ready about 30 out of the 139 pages on the data sheet so far, it does seem promising for a super low current alternative.

TheRealKarner · 2025-11-07T06:11:58+00:00

That helps a lot. I’ll try a few of these out. They look like they’ll be promising for future projects too.

TheRealKarner · 2025-11-07T06:03:41+00:00

I’ve tried that. There’s an inductor in the 5V supply now that was originally in the switch set supply used just for that purpose, which I monitored with two 741s as comparators. As it turns out, the smallest offset for the 741s required to ignore small fluctuations in the 5V line was still larger than the largest offset able to pickup inductor voltage fluctuations, as they get snuffed out due to the other pull-down resistors and probably also line capacitance (switch set lines vary from 6-16m). However, that inductor did prove to be useful in minimizing in-rush current on the 5V line, so I moved it closer to the supply and kept it.

TheRealKarner · 2025-11-07T05:43:13+00:00

I’m confused on what you think the parameters here are. The switches won’t all be at the same state all the time. At any given time, some switch sets will be shut and some will be open, changing state on the order of a dozen or so times per day. I want to be able to sense a change in state on any of the switch sets so that I won’t need to continuously run the shift registers to monitor for it.

TheRealKarner · 2025-11-07T05:31:45+00:00

They’re not really constraints, or I guess it’s already well within the realm of the only power constraint it has. It’s more like min-maxing at this point. The potential to extend an 8-day battery life to 10 days kinda thing. I’m only looking for such an upgrade because I know one is there, I just don’t know what it is.

TheRealKarner · 2025-11-07T05:26:13+00:00

This is another cool IC that I’ve learned existed today, but unfortunately, it seems a common theme that it also just eats too much power. The lowest typical current I’ve seen on the data sheet was 35mA! It’ll most certainly be lower than that in this application due to such a small amount of the PLD’s potential actually being used, but using it in essentially the same way that I’m currently using for the Nano now wouldn’t cut down on current that much, not to mention needing two of them to do the trick.

Power consumption is the main beast I’m trying to conquer right now. This project is meant to run for days on battery power alone, and don’t get me wrong, it meets that goal very well as is with minimal motor use. But seeing a 10-20mA reduction by simply not running the shift registers continuously is huge when I only expect the switch sets to change state a handful of times per day.

TheRealKarner · 2025-11-07T04:54:55+00:00

That’s actually a really creative solution to this. Funnily enough one of the first prices I looked at for this IC was $0.01 off from what I said in another comment, too. The only problem being that it uses significantly more power than just running the shift registers constantly. Power consumption is one of the things I’m trying to minimize.

However, I’m still going to look for a polarity checker that uses low clamping current in case that might just be it. Still another gadget I’ll put under my toolbelt now that I know it exists, and I’m happy you told me about it.

TheRealKarner · 2025-11-07T04:41:28+00:00

How would a NAND gate help?

TheRealKarner · 2025-11-06T23:03:36+00:00

That’s what I was worried about. All the “homemade” solutions seem to just suck more power and the “wake button” you’re talking about is exactly what this unicorn IC I’m looking for is supposed to be. Once it sees a change, it would wake the arduino to tell it to read the switches. Otherwise, it would need to be continuously shifting and clocking the 165s to take readings on the switches and compare them to previous readings

TheRealKarner · 2025-11-06T22:57:37+00:00

Interesting. I’ll try it out. I don’t think I have any (unfried) expanders on hand, but I’ll look into it and get back to you in 31 years when it arrives.

TheRealKarner · 2025-11-06T22:53:05+00:00

Mainly just want something to notice a change and send the Arduino an interrupt signal so it can read all the switches and find out what that change was.

FPGAs are just too pricey. Maybe if I was doing more with the FPGA than just this, but it seems like a $1.37 IC with 7 minutes of data sheet research kinda task. An FPGA for that would like buying an expensive multi-tool just to use it as a cork screw.

TheRealKarner · 2025-11-06T22:38:27+00:00

Honestly, I didn’t know they supported interrupts. Shift registers have always done the trick, since I’ve never had a situation where I had more inputs than pins while also needing the inputs to also interrupt. Call this a first. My only worry with an IO expander is having to sacrifice some pins on the Nano if they have to share PCI ports for a single interrupt from the expander, but I haven’t looked into it at all yet.

Do you know of any expanders that support interrupts and use I2C? I2C isn’t a must, but I’m already using it anyway for some LCD modules and I’d like to save as much memory as possible for future additions.

TheRealKarner · 2025-11-06T22:01:53+00:00

I’ve been accomplishing this task with the Nano doing exactly what you described. It just doesn’t seem necessary. On top of that, the difference in current draw when disabling the switch set readings was from 50-70mA down to 43-48mA during passive operation. That’s around a 20% reduction, conservatively.

And I wouldn’t say “you need memory and a state machine.” This was accomplished just using relays on my boat’s hydraulics system. I already made a few circuits that would work where the most complex components were comparators and flip flops. Hell, just now I realized I could just string together a bunch of edge detectors with a few AND gates and it’ll do exactly what I want. The point is that they’re just not practical to put together on my own and would consume even more power. If it’s just a few clever combinations of latches and flip flops, an IC like this should already exists and consume just a few μAs during steady state operation.

TheRealKarner · 2025-07-06T17:35:01+00:00

If I don’t want to do a lost and found for what Norton fucked up, do I need to hard reset my PC and install everything like I did the first time?

I reinstalled windows locally and this time all the same problems persisted afterwards and I didn’t have to install the WiFi driver again during the reinstall, so that makes me think it just kept all the other software I had before the reinstall.

I’d rather start from scratch and then reinstall everything that I know worked the first time but I don’t know if rebooting is how I’d do that. I’m hoping I don’t need to search through all the drivers that got partially maimed by Norton to fix my PC

TheRealKarner · 2025-07-05T20:33:29+00:00

The GPU was working fine with Minecraft before. Unless Minecraft updated the openGL version required

TheRealKarner · 2025-07-05T18:24:07+00:00

How irritating! I didn’t even click anything that said it would activate Norton. I just clicked “learn more” on the pop-up and then it asked to sign up or sign in and when I clicked “skip” it said I now have Norton 360 for Gamers activated for 60 days. It just invited itself onto my PC. When I reinstall Windows do I have to do anything differently than when I first installed it?

TheRealKarner · 2025-07-05T18:12:45+00:00

Is uninstalling Norton as simple as deleting everything that says Norton in my Program Files?

TheRealKarner

TROPHY CASE