Recent Posts

1

Microcontrollers / Re: Divide clock by 3 on a ATF16V8B

« Last post by Boomchil on Today at 10:33:35 am »

Thank you all for your answers. I have a TL866II so programming it is not a problem, but reading your answers there doesn't seem to be any simple and reliable way to do it, so I've decided to source a dead Sega Master System 2 to get its VDP and use it as an external "divide by 3 only" module.

2

Test Equipment / Re: TinySA Ultra launched

« Last post by shapirus on Today at 10:32:24 am »

First, I think the TinySA is a fantastic project, so thanks very much for doing this!

Yeah that's for sure. Very good value for money: at this low cost you essentially get the functionality, even considering the limitations, that would otherwise require to spend at least an order of magnitude more money.

Besides the actual SA, you're getting a useful RF signal generator, so yeah, this is an amazing product. In addition, at least in my particular unit, the 10 MHz calibration output is very accurate: its actual frequency aligns with my GPSDO reference output to within ~0.3 Hz (~30 ppb), so it can also be used as a pretty decent frequency standard. I wouldn't refuse having a way to tune that to exactly 0.0 Hz, though, but oh well :)

3

Test Equipment / Firmware update 1.23 - GW Instek GPP-4323

« Last post by Fab6657 on Today at 10:30:30 am »

Hello,

Firmware 1.23 is available since few days. I was looking about changelog description but was not able to find any information.
Anyone know something about the changes in this new release for the GPP-4323?

Thank a lot

4

Projects, Designs, and Technical Stuff / Build or buy? Multi-level vessel temperature logger

« Last post by paulca on Today at 10:29:25 am »

"A stainless steel stick with some form of temp sensors distributed along it's length."

* Must be food grade
* Must be tolerant to T>=0<=105*C
* Must be tolerant to high concentrations of:  Chlorine, mild acids, mild bases, alcohol.
* Must be cleanable/sanitizable - ideally detachable and completely immersible.
* Accurate to 0.1C +/- a bit.

The circuitry for the logger I can cover myself I think.

What I'm curious about is....   has anyone seen a commercial product like this anywhere?

Also, if I am to make it what is the best sensor type to go for?  Using "foil" or wire tip thermocouples isn't going to be very durable.  (Thinking of cleaning and storing, think kitchen, not lab).

If I was to make a crude as hell prototype, just to give you the idea, I could take 6 standard curve "stainless steal kitchen thermocouple probes" and lash them to a stainless steal rod at various heights.  Then connect all 6 to the logger board.

While this would work.  It would be difficult to clean with the lashings, handles and cables for bacteria to live.

5

General Technical Chat / Re: Cable Management

« Last post by EPAIII on Today at 10:28:26 am »

And there are commercial cable hanging brackets:

https://www.pomonaelectronics.com/products/dmm-test-leads-and-probes/test-lead-holders

Of course you could roll your own with a board and some wood dowels.

6

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

« Last post by gf on Today at 10:27:38 am »

The original Signal can be reconstructed with much wider filters but they'll only work if the signal is perfectly periodic.
I was wondering what happens if the signal isn't periodic. It could go very wrong.

No, it does not have to be periodic. "Perfect reconstruction" only requires that the original signal sampled by the ADC sampled was bandwidth-limited.

And with a realizable real-world reconstruction/interpolation filter, this bandwidth limit is not 0.5*sample_rate, but lower. For the Rigol, it seems to be about 0.3*sample_rate.

Just make sure that the signal you feed into the ADC does not contain any frequency content above 0.3*sample_rate, and the interpolated waveform you see on the screen will be the same as the waveform sampled by the ADC (at least almost the same -- small residual errors are unavoidable in practice).

If you violate this precondition, perfect reconstruction is not possible and the resulting distortion is implementation-dependent.

7

Microcontrollers / Re: How to create custom bootloader in esp8266

« Last post by eutectique on Today at 10:23:49 am »

Thanks for your help , How do I find the best link for Tasmota project?

Click here.

8

Embedded Computing / Re: WINCE question

« Last post by discomike on Today at 10:21:52 am »

Yes it's like you're assuming.

When building a .Net (C#/VB.net) executable for WinCe/Phone you target the .Net compact framework which is a subset of the normal desktop .Net framework. And the windows PE (.exe) format is platform agnostic so that is why you can have the same .exe and run it on x86 win10 as well as some MIPS WinCE 5.0 =) The IL get's compiled at runtime (or installation).

Some requirements for this to work properly is that the executable is flagged as re-targetable (some option during compilation, can maybe be patched afterwards) and you have to be aware to not use any feature that is not present in both versions of the .Net platform you target.

If you use any native code/dll, you can write your application to load different DLLs depending on what platform you're running on etc.

I used to do this as a quick solution when customers wanted to run some embedded applications we developed on the desktop, without having to provide support/deliveries/testing of a real desktop solution. One alternative here would be to use the mobile device emulator, but that used to be quite slow compared to this approach, but could help you if you need to run some native code.

You also had to be aware that some GUI controls etc behave slightly different depending on platforms and add a few workarounds/tweaks/etc.

Now it's been 10 years since I last touched this stuff, but I did save one customer from having to buy 300 new Android hand-scanners that would only be used for 6 months (during a system migration, of which later they would only need ~30 new units) using this trick (and writing a slim WinCE client for their old PDAs to connect to the new WEB/HTTP/REST back-end system).

9

Test Equipment / Re: TinySA Ultra launched

« Last post by pdenisowski on Today at 10:20:59 am »

The tinySA does not do a continuous sweep but sweeps in discrete steps with possible silence in between. Set the scan speed slow and you will see the step

PLL's locking after the step
I do not mute the output as this would slow down the maximum sweep speed and created larger gaps which you will hear as stronger clicks.
Any stepwise sweep will always have some form of artifacts

Can you explain why these may be a problem?

First, I think the TinySA is a fantastic project, so thanks very much for doing this!

I'm guessing that the "issue" here is that some people may not have realized that the sweep is stepwise: as others have mentioned, a continuous (uninterrupted) frequency sweep is possible on higher end RF signal generators or spec an tracking generators, but these are obviously an entirely different class of instruments at a very different price point

I have to admit that I would have (naively) assumed the sweep was continuous if I hadn't seen this thread. 

Thanks again!

10

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

« Last post by soldar on Today at 10:20:54 am »

The problem is 50Hz will increase the ripple on the smoothing capacitor, so the voltage will drop to a lower level during the troughs. This shouldn't be a problem with a properly designed power supply, as the capacitor should be adequately oversized, but it will be a problem, if it's marginal and perhaps the voltage is also on the lower end of the operating range.

Thank you for explaining and illustrating my point so well.