Recent Posts

1

Microcontrollers / Re: Routines to convert binary to BCD in C code

« Last post by Picuino on Today at 07:10:21 pm »

In this project, the problem was to print 48-bit numbers (16 bits of the main uC counter + 32 bits of the carry counter).
In that case the speed was not important, but to be able to do conversions of many bits. I solved it with custom subroutines for 48bit bit-shift and the algorithm I have previously published.

2

Beginners / Re: 555 driver and Transformer questions

« Last post by xvr on Today at 07:10:13 pm »

Transformer should not be used in this way. There is a strong DC offset in your schematic. Transformer will fall into saturation (that you can see on pictures)

3

Test Equipment / Re: Choosing between entry-level 12-bit DSOs

« Last post by Mechatrommer on Today at 07:03:22 pm »

I just don't know if you measure the length in the same way as I do, therefore I have added the plots to show what I mean with lenght 3.

you can see in the github code i linked earlier. "width property is half a wing" what wing and internal working of it, i havent dig deeper, maybe later. from your description, lanczos width is 2 * wing size, so my wing is 2 meaning lanczos width is probably 4 or 5? anyway you gave me some idea about lanczos limitation related to its width. i'll keep that in mind. thanks and cheers.

4

General Technical Chat / Re: Russia and China to Build a Nuclear Plant on the Moon.

« Last post by tggzzz on Today at 07:02:00 pm »

Get out your red-blue anaglyphs, and see the football

It worked! 👍

Fun, isn't it. APOD has stereo anaglyphs infrequently, so I keep my anaglyph specs handy. A few examples:
https://apod.nasa.gov/apod/ap221217.html
https://apod.nasa.gov/apod/ap240117.html
https://apod.nasa.gov/apod/ap211023.html
That last one is a good example of why stereo photos can be better than flattie photos.

But then I've been taking stereo pictures for 40 years, and have a pleasant collection of vintage glass stereoscopic slides.
https://vintagestereoscopicglassslides.wordpress.com/

5

Beginners / Re: RS232 intermitted issue

« Last post by xvr on Today at 07:00:44 pm »

Check the voltage level on TX pin of PC. RS232 demand negative voltage there (+/- 12V as I remember). Some PC will not provide negative at all and reduced positive (about 5-10V). Not all RS232 receivers accept this.

6

Programming / Re: Linux Dependency Black Hole

« Last post by tatel on Today at 06:58:01 pm »

Hi tatel, That is interesting.
Yes I have downloaded the firmware  C files from git  and have been examining them. But I dont have C IDE or debug, (And not used C for 36 years, so a lot to learn)
So thought MCUX and a devel board  would give me everything including debug.

Also I have been thinking today, with the ease of uploading the firmware, and as I only need < 10 frequencies I could just build 10 firmwares each with a fixed dataset for the Si5351.
A little UI and bash to replace firmware on frequency change , and with the latest Gnuradio ( python based)  which allows users to build their own DSP,     could be an easy solution at least initially

Yeah, even not being a ham, that looks good. Using GNU-whatever looks right to any linux talib 

Using an IDE to build just a firmware binary file looks like using a battleship to go after a trawler to me. YMMV. You could have a look at this:
https://opensource.com/article/19/7/introduction-gnu-autotools.

Probably even a one-liner calling gcc would be enough for that.

Debugger: https://sourceware.org/gdb/

If you are so inclined and absolutely need to have an IDE, you probably could use Eclipse anyway, but then there you go again installing something not in the Debian repositories?
https://wiki.debian.org/Eclipse
https://www.eclipse.org/downloads/packages/release/helios/m7/eclipse-ide-linux-developers

Hi tatel, I don't yet have an R Pi here, I use industrial computers running on 13.8V DC , the main one is Aaeon 6651 https://www.aaeon.ai/en/product/detail/boxer-6641
No problem with capacity.

Oops, got that wire from metrologist, I'm afraid.

7

General Technical Chat / Re: $20,000 dollars of software or licences on a thumbdrive ?

« Last post by strawberry on Today at 06:57:26 pm »

in case NAND chip is readable someone may try to copy contents
something like this

8

Beginners / Re: The old "Replace blue LEDs with red LEDs" 7 segment question (74HC595)

« Last post by xvr on Today at 06:56:42 pm »

> the 595 could be replaced with a stronger version

They could (tpic6(a/b/c)595). But they has different package, not compatible with PCB for 74HC595. And different pinout.

9

General Technical Chat / Looking for reverse osmosis with less than 25% waste

« Last post by Miyuki on Today at 06:53:09 pm »

Are there any people with knowledge about reverse osmosis?

I know some industry-scale systems can do this. But I want it with a small (medium) system with a rate of demineralized water of about 1 l/min.
It will be fed with relatively highly mineralized ground water (plenty of Mg and Ca). And I do not like to throw plenty of water to waste.

Do any of you have some experience with it?

10

Microcontrollers / Re: Routines to convert binary to BCD in C code

« Last post by cv007 on Today at 06:51:49 pm »

and dumped the count by UART every second

That is one of the points I am making- speed of conversion does not matter at all if outputting only every second. Even when you want to dump lots of (formatted) data it matters very little.

You original post was focused on the conversion speed, but if you had actually output all the data at your specified 9600 baud (960 bytes/sec) you would have found out that any formatting you can come up with will be blocking on the uart as it sends out the data, whether you used the arduino print which you had access to or your own custom bcd conversion.

Do what you desire, but using existing code for formatting such as printf or arduino print will be plenty fast. Code size will also be of little concern unless you have a 4k or less mcu. In the case of an avr, the printf code is about 1.5k and once brought in you can use it as much as you want (so use it for everything that needs formatting). For arduino (which I don't use) I imagine no one using that will concern themselves with how the details of formatting are done as they just use print when the need arises.

printf( "%lu\n", my10MHzCounter() ); //%lu for 32bits on avr
Serial.println( my10MHzCounter() );