Recent Posts

1

Beginners / Re: How Current Limitation is happening in the circuit???

« Last post by Xena E on Today at 02:48:20 pm »

I'm very sorry Ommsiva your pictures seem deliberately not to show any detail, at all.

Pictures of the tops of T03 transistors may be useful in identifying the type numbers but don't convey anything about the connections made to them.

Two front panel photos ... of similar value.

A general internal shot of a disassembled rats nest of wiring.

All of the above at a resolution such that even if it were tidy construction and complete it couldn't be of any less use in assisting with your query.

As you seem to not like answering direct questions about your project, then the purpose of this thread is clearly intended as a piss-take of the kind people who have tried to help you.

Have a nice life.

X

2

Microcontrollers / Re: primitive serial CLI / Console for embedded systems - Ideas for implementation?

« Last post by nctnico on Today at 02:46:18 pm »

What works for me is a struct like this:
struct TCommand
   {
   char *command;
   void (*func)(int argc, char **argv);
   char *helptext;
   };

which is used to create an array with commands and help texts. I use a buffer which only receives text (>=32 <127). When a 13 is encountered, the input buffer is split by spaces, the space replaced by 0x00 to mark end of string and an array with pointers to each parameter is created. The first entry into the parameter array is the command. Iterate over the commands to find an match and call the callback function. Note that the callback function is exactly like the main function of a 'regular' C program.

Every piece of embedded software I have made or worked on has a CLI and this has been proven to be an immensly useful feature for development, integration testing and field debugging (logging & fault finding).

3

General Technical Chat / Re: Dumpster diving save VFD

« Last post by Alex Eisenhut on Today at 02:45:35 pm »

I see a lot of wires, does this module have a serial port? Some of them have a small 3 pin header on the board for serial. I think it even breaks out to the parallel header

4

Other Equipment & Products / Re: Three most useful tools I got from AliExpress

« Last post by wraper on Today at 02:45:30 pm »

It's one of the most useless tools I have. It sucks at everything besides that it actually holds the board. The only way it's useable is if you insert TH components and bend the leads so they don't fall out before putting it in holder. Inserting while in holder is a no-go. Not to say soldering under angle means that solder tends to flow downwards, especially on large solder joints. Frankly board just laying on the desk works better.

Are you talking about this specific holder or about holders in general? Personally I find board holders very handy when I use the desoldering pump instead of the gun.

I'm talking about this type of holder in particular. Maybe it's ok if desoldering with solder sucker but when pulling component from opposite side it often obstructs your hand/tweezers.

5

General Technical Chat / Re: Is LinkedIn worth keeping?

« Last post by coppice on Today at 02:44:22 pm »

LinkedIn web site is the text version of TikTok and a model of a garbage useless web site.

Yes, LinkedIn is terrible. It would be easy to create an effective portal for connecting professionals, and LinkedIn is so bad it shouldn't be hard to make people migrate to it. That hasn't happened. I find that interesting.

6

Microcontrollers / Re: SD Card reliability in SPI mode

« Last post by Peabody on Today at 02:44:01 pm »

It sounds like you're pretty much locked into the software package, but for future reference there's an alternative that does all the file system setup ahead of time, including creating all the files and low-level erasing their data segments, and after that you just write data to successive sectors on the card.  There's no need to mess with the directory entry or the FAT, or do any sync or flush operations.  Or Open or Close the file for that matter.  You are simply writing into the sectors that have already been defined as part of the file.  The LowLatencyLogger example in the SdFat library shows how this can be done.  I would think this approach might cause the least problems if you are cycling power to the SD card.

7

Projects, Designs, and Technical Stuff / Re: Help with DIY guitar pedal

« Last post by mag_therm on Today at 02:42:18 pm »

I had a batch of those pressed wafer type of 1/4 mono jack.
The solder tag can be open circuit I think due to poor press during manufacture.
Intermittents there can be tricky to find , they work on bench test than fail while the musician is dragging the cable around .

8

Metrology / Re: DIY 0.1 to 10Hz Noise Amplifier

« Last post by MegaVolt on Today at 02:41:43 pm »

There are also battery measurements performed by Walls at NIST, time-frequency group.
I think the filename is 1111.pdf, but it is a moving target on their server.

https://tf.nist.gov/general/pdf/1133.pdf

9

Mechanical & Automation Engineering / Re: Paint Bubbles On Snowblower

« Last post by T3sl4co1l on Today at 02:40:16 pm »

I would guess pinholes letting through the tiniest bit of contamination; could be ambient salt spray (e.g. sweaty dust, road dust, partially melted snow, etc.), condensation, just high humidity; and, if the paint is tight otherwise and the rust is black, it would seem to be Fe(II) i.e. a reducing atmosphere, oxygen-poor, so at least it's going slowly, and that means the paint is mostly doing its job except for where it's been compromised.  Unfortunately I don't think there's much to do about that, other than grind it down and repaint it, and get it coated in enough layers to be sure it's not pinholed.

Possibly a microscope can confirm pinholing, but you'll have to inspect a lot of surface to tell, probably with a good scope, and... whatever.  I suppose if you can do a fluorescent stain process that would be handy.

When done in use, keep it hosed down with fresh water, let it dry out, I suppose; keep it in a dry place, etc.  About all you can do now is reduce continued growth.

Probably the engine, gearing or impeller(s) wears out before panels rust completely through anyway, and if not, patches are easy enough to weld in place (assuming you are so equipped, or can get someone to do it economically -- even a top professional should be able to do that for a couple hundred bucks, well under the thousand ish sale price of a new one?), then grind down and repaint.

Tim

10

PCB/EDA/CAD / Re: JLCPCB alters soldermask without any notice

« Last post by Kean on Today at 02:40:09 pm »

After uselessly poking around the website, I finally found it using Google. Thanks.
https://jlcpcb.com/help/article/592-gerber-files-preparation

They don't even have an extension for what I idiosyncratically call my paste layer. I don't think I've ever ordered a stencil from JLC, come to think of it. It's just in my default gerber CAM job for the occasion I need it.

Their file naming conventions are pretty common, e.g. as used by Altium (with my OutJob settings at least) and Eagle/Fusion Electronics.

The paste filenames would be boardname.GTP and boardname.GBP

I've had approaching a hundred stencils from JLC using that filename convention and the layer files have always been automatically detected correctly.