Recent Posts

1

Beginners / Re: Blocking Phantom Power 48V from Audio output

« Last post by Saimoun on Today at 01:33:52 pm »

What do you mean with "phantom power"?

Like the 48V that an audio mixer can send over an XLR cable for example. As I understood it is typically raising the DC voltage from 0 to +48V on both pins 2 and 3 through a 6.8k resistor.

However you need to double the capacity of the 22uF to 47uF or something like that, because capacitors in series act the same as resistors in parallel.

Very good point I did not think about that! Actually what about the discharge - would that not damage the first cap and/or the opamp behind it?

2

FPGA / Re: Help on translate schematics to Verilog.

« Last post by xvr on Today at 01:32:48 pm »

> I have these other two KiCad symbols that I'm try to identify,

If you have KiCAD schematic file you can fetch type of symbol from it. Just open it in KiCAD, select symbol and press 'E'.

3

Security / Re: Microsoft repackages apps with a telemetry .NET wrapper

« Last post by PlainName on Today at 01:31:43 pm »

Some developers use telemetry to figure out how people use their software

Shouldn't that be done in-house, or at minimum with users that agree to be monitored?

But users do agree to it. That’s why software installers literally ask you whether you agree to share usage data or not.

No problem with those that do that, but those aren't what's under discussion here. With many apps you get told they will use telemetry and that's your lot. Others will offer you the option to opt out of some telelmetry but not all. And it should be opt in.

Any legitimate vendor makes it clear what is and isn’t collected. (For example, that your data itself won’t be shared.)

Unless 'anonymised'. Or shared with trusted partners. Or similar wishy-washy things.

Are you happy with your car telling the manufacturer where you went, what speeds you did where, how you used the brakes, your acceleration, where you were looking, how you flash the lights, etc? What time you go to work, the shops, hey - is that the place where Ms Periwinkle's car is parked and it's always 8pm to 10pm?

Completely different from usage statistics.

A correct analogy would be that it shares things like: what percentage of the time is your foot on the gas pedal? How many times do you use the brake on a typical drive? What’s the average length of your drives, in km and in minutes? What’s your acceleration style (jackrabbit starts or slow off the line)? How long is the car idle between drives?

Not sure I want anyone to know any of that! It's just a matter of degree, isn't it? Where one draws the line. And don't forget we are on about those not asking permission but just gobbling the stuff, because.

The stuff you list is more like if Word was sending not only that, but also uploading your documents and a live keyboard log.

I am absolutely aware that some companies, like Google and Meta (and the essentially scammers who make “free” phone apps whose main raison d’être is to collect user data), do collect and upload all kinds of sensitive personal data, like location logs, to use for commercial purposes.

Check up a little bit and you'll see that this is about those 'some companies'. Microsoft is definitely not an innocent in this.

4

Beginners / Re: Convert US standard 115V to International 230V

« Last post by BeBuLamar on Today at 01:19:37 pm »

IanB suggested to use the Kill-a-watt which is kind of cheap but it's not Chinese. It's Taiwanese. The Taiwanese is not pleased if you call them Chinese.

5

FPGA / Re: ATF1502 programming & 'wrong' id (fake?)

« Last post by dolbeau on Today at 01:18:35 pm »

Thanks for the answers.

The JTAG circuit is fairly trivial - just the pin header for the USB blaster [clone], and the ATF1502ASL, nothing else. Pinouts was double-checked against both the datasheets and for the ATF1502ASL the original design (it has a different connector). SVF file for basic stuff like erase, and for programming+verify, all work with no issue provided they are changed to the actual ID of the chip.

Preliminary tests with a much simplified code in the CPLD designed purely for testing suggests the chip works as advertised, at least with this simplified design. So it's likely the chip are actually ATF1502ASL (or clone thereof), and probably close enough for my hobbyist use case.

But still wonder why those JTAG IDs are 'wrong'...

6

Projects, Designs, and Technical Stuff / Re: Homebrew Lock-In Amplifier

« Last post by Kleinstein on Today at 01:18:17 pm »

With very high gain and precision in mind it is usually better to have a single ground point (star ground). A ground plane is more thing to avoid EMI and good for a digital circuit.
The point with a lock-in amplifier is to keep the input and reference part separate, so avoid the ref. side to cause any input signal with the same frequency. In the plan there is not yet much for the ref. side. For quite some applications one would want a phase adjustment there.
One would want at least some protection.

If one needs fine steps with the gain depends on what is used to read / display the output: with an analog meter one may need 1, 2,5,10 steps for the gain. With a digital read out with sufficient resolution steps of 1 , 10, 100, 1000 are enough. Only a gain range from 1 to 100 may be a bit small. 
Depending on the precision of the amplifier at the input one may want a 2nd AC coupling step before the phase sensitive detection.
The display / output side also determines how much gain is useful at the output (DC) side. With a rel. low resolution ADC or an analog movement one can use quite some DC gain there. Chances are the AD630 output can be stable to something like 10 µV. So the output side should ideally be able to resole to that level. If a good dmm is used the range settings there can provider some of the total gain.

7

Programming / Re: Linux Dependency Black Hole

« Last post by mag_therm on Today at 01:10:01 pm »

Thanks for the encouraging replies.

The software project I did was actually the largest  single project of my whole engineering career,
It is a numerical simulation of electro thermal process.
Took more than 5 years for me to develop, about 350 k lines of code and uses multi core parallel processing.
Trips around the world to various steel processing plants to measure and verify the accuracy.

At the start I intended multi platform and was going to use C.

Due to deployment and maintenance world wide and expected life of 20 years,
I looked at various "friendly" IDE and eventually selected Xojo.
There were to be no dependencies and the whole application was to be in user's space.
I used a pro programmers initially to do the GUIs and the sqlite.
And client's engineers assisted with scada/plc interfaces

Fairly early in the project, having trouble, we decided to abandon multi platform and just use linux.
We were fortunate that the original code and graphics continued to function over many Xojo updates from 2008 to 2019.
 But in 2019 XoJo did major changes to graphics and so we also had to do an update taking a few months

I suppose all that total experience is how I came to dislike dependencies and to rely on IDE !

And yes, I am partly doing this HackRF1 firmware job to try to keep up to date, as well as hopefully improving the FOSS firmware.

8

Thermal Imaging / Re: HTI HT-203U 256×192 thermal imager for Android phones

« Last post by ArcSin on Today at 01:09:35 pm »

Anyone has any clue where you could get the Tiny1-C 256x192 infrared module without the rest of the dongle?

I have seen cheap dongles that contain it, but when i try to look for actual module without anything else, the price goes up like it just spotted a spider on a toilet chair.

9

General Technical Chat / Re: Cable Management

« Last post by Wallace Gasiewicz on Today at 01:06:52 pm »

I use something like nfmax.  I use storage bags and put them into expandable files. These are the ones for paper files and kinda resemble accordions..

10

Thermal Imaging / Re: My decent in to Infrared abyss (IR microscopy and telescopy, on the cheap)

« Last post by ArcSin on Today at 01:06:27 pm »

Thanks for sharing, definitely will have a look!

Also, 150mm f/1 IR lens? That cost like arm and a leg.