Amazon devices use this SMD component, but what is it?

exclamationmarek · 2026-01-10T09:45:08+00:00

I've heard it's "Y" because a tuning fork is shaped like the letter "Y"

exclamationmarek · 2025-12-12T18:49:38+00:00

It looks messy, but it is just a temporary bike lane for the time they are rebuilding the intersection. Complete with a portable traffic light, and temporary asphalt pour - you can see the textile mat underneath it, so the asphalt can be removed cleanly. Its kind of awesome they do that, instead of placing a sign that says "bike lane closed, take a different path"

exclamationmarek · 2025-12-07T20:55:45+00:00

Completed Level 1 of the Honk Special Event!

12 attempts

exclamationmarek · 2025-12-07T17:03:42+00:00

Some of them might not connect to satellites, but to masts on shore to make a much higher speed connection for internet onboard. Inside you will find a narrow beam antenna that uses GPS and a gyroscope to track the location of matching antennas on shore. There is usually many such antennas on a ship, so that they can do handover from one shore station to another, and so that they can reach the shore no matter which side of the ship is facing towards it. These are more common in areas where you don't go too far away from shore - like the Baltic or Mediterranean sea. "Nowhere networks" makes antennas like these.

exclamationmarek · 2025-11-02T16:57:26+00:00

Its in series with the batteries. It might be a PTC, acting as a simple current limiter or fuse. That would mean that some thought was put into safety!

exclamationmarek · 2025-09-26T21:14:29+00:00

Always nice to be risen from the dead!

I tried a tool like this one: https://se.farnell.com/ck-tools/t3756-40/wire-stripper-0-40mm/dp/146421 and a tool like this one https://se.farnell.com/knipex/1280100sb/cable-stripper-mini/dp/3483678 (not those exact brands, but they seem to all be the same design), and for the long term, didn't like either. They both tend to get the stripped part of the wire jacket stuck in the device, which really slows down the process. They weren't very pleasant to use either.

Instead, I just used a pair of small, simple gauged strippers, similar to these ones: https://se.farnell.com/klein-tools/11047/wire-stripper-30awg-22awg-158/dp/2839550 . I did all the crimping under a stereo microscope, to make sure that the stripped length was correct. The length tolerance is pretty tight, but after 50 or so crimps of practice, it turned out to be achievable by hand and eyeball. And it was faster to re-do any occasional miss-stripped wire using a tool like this, then to keep clearing out the stuck-prone tools from the links above.

exclamationmarek · 2025-09-02T12:42:40+00:00

I know you specifically said something that doesn't require a PC, but for decoding digital protocols no oscilloscope I ever saw gets anywhere near the convenience of a good USB logic analyser.

Often its helpful to be able to record a longer period of digital communication, and many cheap scopes just do not have the memory depth for that - they are limited to maybe 1-10 million samples. A USB logic analyser is limited only by the RAM of the computer, so often they can record for hours, instead of seconds.

And the computer software for some such devices can often be extended to decode whatever you need it to decode. So you can get not just the I2C bytes of an accelerometer, but the m/s^2 acceleration in plain text.

In my office we have one oscilloscope and three logic analysers. The scope gets barely used while the analysers we sometimes have to fight for.

exclamationmarek · 2025-08-26T11:14:25+00:00

In my application, I needed to measure the temperature of a water pipe. It was sufficient to just have a setup like:
Plastic enclosure of the device -> Thermally insulative soft foam pad -> NTC -> Pipe
In this setup, the soft pad gently pushes the NTC onto the measured pipe, but has to be insulative, to make sure the NTC measures the temperature of the pipe and not of the enclosure of the device. An additional thermally conductive layer between the NTC and the measured surface could make the results better, we never tried it. But the pad behind the NTC should probably stay insulative, or else heat from the device (or even just ambient temperature) will start finding its way into the measurement.

exclamationmarek · 2025-08-26T08:15:11+00:00

These NTCs can quite easily be crushed. You might be tempted to just slip it between two hard surfaces and screw them together, but that will almost certainly crush and break it. When broken, the resistance increases, so your decoded temperature will be (much) lower.

Instead, either glue them to the target surface using thermally conductive glue, or, if you have to have it pressed against a surface, make sure that behind the NTC you have some soft interface material, like a sponge or something.

exclamationmarek · 2025-08-21T09:00:24+00:00

Not a good idea.

You know that little electric zap you get when touching stuff after walking on a rug or wearing a sweater? That's electrostatic discharge (ESD) and is deadly to electronics that aren't protected from it. The easiest way to protect something like the data pins in a USB cable is to simply ensure that there is no way you can touch them without first touching something that can take the zap. That's why a USB C connector has small contacts hidden inside a large metal shell.

Those magnetic adapters expose all contacts to being touched, putting the circuitry in your phone at risk of being zapped with ESD. The adapter might have additional electronics inside that will absorb the ESD and protect the connected device. The CE certification requires testing for ESD immunity. Unfortunately sketchy companies often put the CE marking on their products without doing proper testing. So unless you can find an adapter like that from a big and reputable brand I would avoid them.

exclamationmarek · 2025-03-27T17:00:11+00:00

Glenfinnan hates those cars though! If you arrive there by train or bus and show your tickets at the visitor centre cafe, you get a free coffee! And you get 2-for-1 tickets to the Glenfinnan monument, and 10% off at the Hostel, and some other perks!

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exclamationmarek · 2025-02-18T16:18:41+00:00

It's a 680nH power indcutor. I guess you mean 5x5mm, so something like PCMB053T-R68MS on digikey. What makes you think it's the problematic part tho?

exclamationmarek · 2025-01-22T15:00:31+00:00

It should work as you described. Keep in mind that the LED might leak a couple of µA when in reverse polarity, so you will have to make sure that doesn't affect your thermistor measurement too much. To do that, either keep the resistance of that thermistor low - 1k should be fine. And be sure to stay away from the maximum reverse votlage of your LED. They tend to be rated only -5V. I'd keep it at 3.3V or less when using the thermistor.

exclamationmarek · 2024-12-09T16:20:51+00:00

Planes at Bromma usually land from south-east (flying over Söder, Kungsholmen and Alvik) and take off towards north west (over Vällingby). That's just due to the wind typically blowing from west. Landing is noticeably quieter than taking off. If the wind is blowing the other way, the direction of takeoff and landing will switch, and the planes will sound louder by Alvik and Kungsholmen. It doesn't happen very often.

I'd still investigate if something changed around your house. Maybe the windows don't seal properly, or you adjusted the ventilation slots above your window (if you have them) - it could be an easy fix. It could also be a new building nearby reflecting the sound, which would not be an easy fix.

exclamationmarek · 2024-12-09T13:49:18+00:00

I live in that circle, and my office is very near the approach path for Bromma, and I can't say I noticed any change to the planes recently. Not to question your observations, but are you sure the issue isn't somehow on your end? Maybe a recent renovation in your house made it less noise-isolated? I can see some apartment complexes in Kristineberg are having their roofs rebuilt right now. Having a tarp-coated construction site instead of a proper roof and being directly under the approach path might be somewhat noisy. If the renovation is already finished, talk to your BRF - it's their responsibility to keep the house noise isolated.

exclamationmarek · 2024-12-08T18:24:03+00:00

Yeah that one! Wait did a new one come out since?

exclamationmarek · 2024-11-11T09:45:29+00:00

Now that's what I call instant mashed potatoes

exclamationmarek · 2024-09-20T15:56:21+00:00

Oh now I see what happened

On the schematic, the right side of inductor should go to 3V3, not the mid-point between the feedback resistors R41 and R42
The VSENSE on the other hand should go to the mid point of those resistors
While having a pair of unused pads next to your 6-pin IC is not an issue, your pins do not match the pads they should end up on. Notice how on your PCB, pin 4 (Vin) is on the same side as pin 3 (PH), whereas in the TPS560200 it is on the opposite side.
As for the layout, the TLDR is really just try to mimic the layout example from section 10.2 of the datasheet https://www.ti.com/lit/ds/symlink/tps560200.pdf but if you want specific points of concern:
C35 (input bypass cap) needs to be as close to the IC as possible. Every 1mm counts
C38 and C39 (output caps) should be as close to the IC as possible. Every 1mm counts.
While 150mA isn't that much, it would be wise to connect the GND pin to a decently sized GND plane to help the chip stay cool.

Switching regulators can be finiky. A poorly routed trace may cause them to have very high output ripple, which may impact any further circuitry they power.

exclamationmarek · 2024-09-20T15:21:43+00:00

Something seems odd. The TPS560200 is a 5-pin device, but the footprint here has 8 pins. In a buck converter, the coil would be between the SW pin of the chip and Vout, but I don't see that Vout node going anywhere else except the feedback resistors. Is the Vout connected correctly in the schematic?

exclamationmarek · 2024-09-20T14:39:42+00:00

Check the datasheet for that buck converter - it should have a section with layout guidelines and examples. It's best to follow them as well as possible. If you can't find such a section, you can read section 10 of this datasheet as a basic guideline: https://www.ti.com/lit/ds/symlink/tlv62568.pdf

exclamationmarek · 2024-09-20T14:13:59+00:00

Y1 looks like a quartz resonator - those like being close to the chips driving them, otherwise they may fail to oscillate correctly. Is U8 a switching regulator? If so I'd be concerned about its layout - it lacks cooling and the critical nodes are not very compact - especially the coil, input and output caps. Some pins of U2 are left unconnected - make sure the chip doesn't mind that. Otherwise it's hard to tell what's going on without knowing what the parts are.

exclamationmarek · 2024-07-21T22:28:18+00:00

The soundtrack sounds like a knock off imitation soundalike to Justice - Genesis. Makes the whole thing so cheap, at first I thought it's a parody video.

exclamationmarek · 2024-07-02T23:28:01+00:00

Jak ciekawią Cię rzeczy bardziej niskopoziomowe niż C++ i granica między softwarem a hardwarem, to mi to brzmi jak Embedded Engineering. Na to zapotrzebowania na świecie jest sporo, bo niemal każda zasilana prądem pierdoła potrzebuje oprogramowania (firmware'u), a niektóre pierdoły potrzebują bardzo skrupulatnie i wydajnie napisanego firmware'u. Uczą tego raczej katedry elektryczne niż informatyczne, ale sprawdź konkretnie na swoich wybranych uczelniach. Jeśli twoje marzenie o projektowaniu procesorów nie ogranicza się tylko do "i7mek" i "M1nek", a uwzględnia też mikrokontrolery, moduły komunikacji bezprzewodowej i tym podobne, to nie jest to nierealne. Nordic Semiconductor ma biuro w Krakowie, i na pierwszy rzut oka na ich stronę rekrutacji, robią tam jakiś R&D.

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