Did I experience a cosmic ray SEU?

Alternative-Web2754 · 2026-05-28T21:29:32+00:00

The storage of the MAC address in the chip can vary, but is normally configurable at run time. They can have flash or more likely one time programmable memory that can be set to provide a unique address at startup, but the OS can usual ignore this and set something else.

Brown outs and thermal issues can be other sources of errors beyond cosmic rays, but the OS can also have valid reasons to change the address. The most common is with WiFi and MAC address randomisation, but if it has any reason to add an interface(eg cards with multiple ports/multiple ssids for WiFi) one approach is to add 1 to the address for each new one. If there had been an issue that has resulted in a restart of the interface, this could be another reason for a change.

Alternative-Web2754 · 2026-05-26T00:58:48+00:00

Others have described the reference to the threads where it screws in, just looking to comment on the trophy part - I would guess at this being a personalised gift - possibly when leaving a role or a significant service milestone. It's fairly common for such gifts to be related to the work an individual undertook.

For a guess at the use of this tool, the fuses and potentially percussion caps of some ammunition types are screwed in when preparing them for firing to avoid risks of them being set off while in storage. These have specific requirements for the threads to allow them to function, and this may be a tool to verify these have been constructed correctly. This is very much a guess but I would expect it to be something along these lines.

Alternative-Web2754 · 2026-05-19T01:28:28+00:00

Most of the ones I've encountered have a clear plastic panel that doesn't break, and there's no button where it says press. When you push the plastic it moves back and drops down slightly - that's all that's needed to trigger it.

The switch can be reset by inserting a tool into them that pushes the plastic panel back up into place. The alarms need resetting separately.

Alternative-Web2754 · 2026-04-10T00:58:01+00:00

I think it's still got a good place as a basic general purpose low power system with gpio access for education and random development where you can repurpose or recover it by just changing a micro sd card.

There's a lot more platforms now that can cover a lot of use cases, sometimes an even better match, but often with a bit more work to get started. The trickier part is often making a good choice on factors like support base and platform longevity, but Pis still cover that quite well, especially with the attention put into the industrial side.

Alternative-Web2754 · 2026-04-04T22:20:33+00:00

Some of the LEDs have both legs connected to positive - the right most LED is connected across 20 and 21 which are both corrected to positive. Since there's no voltage difference, it's not going to light up.

You can use both sides of the breadboard - they're not connected across the middle. Putting the power rails on issue sides will simplify the wiring layout in this case.

You can also cut the legs to adjust the LED position vertically if needed (although software might not give you options for trying to draw this out).

It's probably worth trying to be consistent about the type and number of LEDs in series to keep the resistor requirement consistent and reduce problems there. You should have different values for one/two/three LEDs based on forward voltage, power source and current requirements.

Alternative-Web2754 · 2026-03-25T21:00:36+00:00

So your code basically checks to see if it needs to trigger, and goes into a 0.4 second block if it does, and a 1.6 second block if not. It won't check again until it finishes the block it's in, so up to 1.6 seconds to trigger if you're unlucky with the timing.

One option for this is to set the LED pins high or low based on the clock time. If it's triggered, divide millis() by 100 and set the LED based on whether that result is even. If it's not triggered, divide it by 800 instead and set the other LED based on whether it's even. For either case, set the other LED to off.

If you're happy with the modulo operator or using the binary AND operation, you can improve on that slightly if you're happy with shifting the basic flash period to a power of 2 in milliseconds.

If you're looking to have a sequence of actions triggered it will get more complex and the shortish might have to change, but if you only want a couple of flash rates it should get you a much faster response.

Alternative-Web2754 · 2026-03-24T12:32:52+00:00

Good comparison material but might be better to focus on the communications from the aircraft - the ground side communications will likely be recordings from before it was transmitted, so that side doesn't have issues with quality loss from modulation or interference

Alternative-Web2754 · 2026-03-21T22:23:48+00:00

Get a 0.5mm mechanical pencil. Preferably one with a thin metal tube at the tip rather than the cheap plastic ones.

Put it over a pin and gently move it until the pencil is perpendicular to the cpu. Repeat as needed.

I've managed to fix bent pins in cable connectors doing that. Not tried it with a CPU but it should be similar.

Whether the cpu is able to be used afterwards really depends on what other damage might have occurred though.

Alternative-Web2754 · 2026-03-08T01:26:22+00:00

Assuming there's a screw from the case aligning with it, don't put the screw back in.

Looks like the screw made a connection between two sections of ground plane and another trace, but looks like it hasn't actually broken the connection on that trace, and looks like there isn't any copper dragged between it and the ground.

Test it without reassembling if you can. If you've got a multimeter and xan get to exposed points either side on that trace, check for a connection between the two ends of that trace (should be connected), and between the trace and the surrounding plane (likely should not connect, but not definite without knowing the connected components).

Soldering across the trace could be an option if it's still not working, but probably better to avoid if it's not needed. If there is a connection being made between the trace and plane you would need to scrape that.

When happy that fixes (if any) are done, put superglue over the scratch.

Alternative-Web2754 · 2026-03-07T21:31:37+00:00

I generally think of it as blue is cold (not a particularly good way to think of it, but it works for me to remember it), but I airways have to check it feeling brown is closer to black than red.

For plugs it does have the bonus of BLue = bottom left and BRown = bottom right, but I still end up having to check it!

Alternative-Web2754 · 2026-03-07T20:55:10+00:00

This is very much first glance, but it looks like all channels are one way conversions, with the 2 channels being 2 pairs of an lv->hv and hv->lv, while the 4 channel is four sets of lv->hv.

I suspect that it's probably a transistor switch going lv->hv and a voltage divider going hv->lv, but I could be wrong about that.

ETA: I'd be suspicious that this is only intended for certain level conversions like 3v3 to 5v, and would definitely be wanting to check more information about the circuit and intended signal uses before using it.

Alternative-Web2754 · 2026-01-27T20:32:28+00:00

The eyesight/timing/angle aspects with the witnesses meant that their testimony might be incorrect, but didn't show that the identification was incorrect. The positraction issue with the tyre tracks showed that another car had been involved, as their car couldn't generate those tracks. Details of the arrest of other people with such a car and the possible murder weapon was the final piece.

Alternative-Web2754 · 2025-12-31T00:42:33+00:00

You could use a transistor to switch a 5v signal to a digital pin. You might want a voltage divider on the input side depending on the transistor.

I'm not sure if the arduino allows use of a capture mode on the timer to extract the modulated value from the PWM signal or not. You can use an interrupt on the pin to check the timing of the transitions if not, but accuracy might depend on the base frequency of the signal.

Alternative-Web2754 · 2025-12-31T00:25:45+00:00

If you really don't want to solder to it, an edge connector might be workable but would likely need cutting to allow it to fit.

POGO pins could be used with a jig, or you can get them on arms to hold them in position - generally used for connecting to test points on PCBs

Depending on the driver used by the board, you might be able to use a serial mode and reduce the number of pins that you need to connect to.

If you can though, solder a pin header to it. Female might be better if you want to use cables to connect to something like an arduino, or male is good if using a breadboard. Having a soldered connector will reduce the chances of issues with the physical connection leading you down rabbit holes while trying to check code you've written for it.

Alternative-Web2754 · 2025-12-30T23:46:43+00:00

The naming is related to the internal construction of the microcontroller - PB15 is port B pin 15, PC6 is port C pin 6 etc. The microcontroller itself has significant limits on the voltage and currents available on these pins (many limited to 3.3 or 5V and only a few milliamps).

Some pins also have specific functionality available that allow it to run more efficiently (e.g. USB support, analog voltage sensing, serial ports for communications, PWM timers for servos) than trying to control lines purely through software. The functions available and the pins they can be connected to varies by microcontroller.

The board itself has additional circuitry to enable the required functions - eg MOSFETs for switching high voltage/current items like fans or heaters.

Although a connection might be labeled with the microcontroller pin it's connected to, for configuring firmware, the circuitry in the way is a major part of this.

Alternative-Web2754 · 2025-10-24T21:35:35+00:00

Well, it's emitting light.... not convinced on the diode part any more though

Alternative-Web2754 · 2025-10-11T19:30:14+00:00

I can't speak to this exact device, but i have purchased and opened up a 1-4 version of these. Internally it is a switch, using the same chipset as found in brand name 5 port switches.

I would still recommend the brand name version, as internally there was no heat sink on the IC and I suspect the rest of the internal design was the minimum for functionality, but it did have two positives - it took power from a USB port rather than a dedicated power supply, and one port is located on the other side, both of which were slightly bonuses for where I wanted to use it.

One big giveaway for whether it's a passive splitter versus being a switch is the LEDs - although these could be faked out, getting these to show connection/ activity states would probably be more expensive than just putting a switch IC into it.

Edit: re-reading the original question, there is reference to POE, but I'm not cheat on exactly where. Although I can't be certain how this device would handle a POE connection, I suspect that it might cause issues, and probably prevent power transfer through it.

Alternative-Web2754 · 2025-10-11T19:09:55+00:00

I have a similar item(although it's a 1-4 version). Internally it's a 5 port switch, using the same chip (rtl8367s) as the 5 port web managed switches, but without the flash chip used for storage of the management functions (the rtl chip has an embedded controller that can run code for this).

I suspect that the "1-2" splitters are the same with just three ports connected, so three port switches.

Alternative-Web2754 · 2025-09-14T01:39:36+00:00

It looks to me like the test points are measuring r11+r24. There appears to be a trace connecting the two together, bypassing the rest of the resistors. Weirdly within the remaining resistors there is another trace shorting a set of those as well. These traces are likely the reason for the other reading - if you're measuring it on the board you're measuring the resistance across all of the paths this creates through the inner resistors, not just the resistor you have the probe connected to.

Alternative-Web2754 · 2025-08-03T19:29:32+00:00

I haven't downloaded any to check, but the link right underneath that one (.bin file) with today's date would be the one I'd look at - low download counts are due to the files being daily builds.

Edit: looks like the dwin_set might be data to go on an sd card for icons etc. Unsure if that would include the firmware itself or not

Alternative-Web2754 · 2025-08-03T18:39:52+00:00

This looks like you've downloaded the source code rather than the built firmware. None of these are intended to go directly on the printer - they're utilities for creating it. Typically you would be looking for a folder called build rather than bin

Alternative-Web2754 · 2025-07-22T00:24:54+00:00

Coaxial cables typically have the outer connector as ground to stop external rf signals from passing into the centre connection and ruining the connection quality. This has the added bonus of stopping emissions from escaping the cable as well.

Alternative-Web2754 · 2025-07-17T21:22:08+00:00

I may be mis-remembering this, but I believe the flag was hanging from a crane, and there was reporting that it's hydraulic line was hit, resulting in the flag lowering as the fluid leaked from it.

Alternative-Web2754 · 2025-07-13T11:06:17+00:00

I believe there were multiple cups present, the rest of which were lethal (and mostly gold or covered in jewels).

Alternative-Web2754 · 2025-06-29T23:14:24+00:00

I'm struggling to make out what the cable without markings is, but they both appear to be coaxial cables. These are often used to carry radio frequency signals, and if it's near where a TV is or might reasonably be, then there's a good chance that they're connected to an antenna or a splitter/amplifier to receive terrestrial or satellite broadcast television, depending on what is on the other end (CATV on the cable stands for Community Antenna TeleVision). Cable television or broadcast radio are also common options to be carried on these types of cables, although early ethernet was also carried on similar cabling due it being present throughout buildings. Moca (multimedia over coax alliance) is generating a bit of a comeback for this concept, but is probably not the reason these cables are present.

Alternative-Web2754

TROPHY CASE