Recent Posts

1

Other Equipment & Products / Re: Different bases on Amscope microscope

« Last post by SteveyG on Today at 09:13:30 am »

There’s a few YouTube vids saying to avoid the articulating ones at all costs

For example

https://youtu.be/dFdrTsDIw24?feature=shared

The articulating ones are perfectly fine so long as you don't use a camera as the vibrations are easily seen.

The double boom type is certainly the best though.

2

EEVblog Specific / Re: EEVblog #1181 - Car ECO OBD2 Fuel Saver SCAM

« Last post by langwadt on Today at 09:12:43 am »

Fuel economy is a big selling feature now. If there was something this simple that could make any meaningful impact on fuel economy why wouldn’t the manufacturer do that from factory. None of these fuel saving gizmos ever work.

theoretically there is a chance that it could work if done right, but it would be at the cost of increased emmisions which is why the manufacturers don't do it

3

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

« Last post by tggzzz on Today at 09:11:33 am »

I would hope they are they type of guy that would use an appropriate tool.

• for many RF measurements that means a frequency-domain or modulation-domain instrument (a scope is time-domain)

with what? 30K$ fieldfox? and 5K$ probe or cables? Sometime looking at presence of carrier will help. There's diy open loop antenna to detect rf etc.. and with cheap item we can do relative measurement of rf power, not necessarily absolute traceable measurement. if you cant do more with less like i can i wont force you, cheers.[/list]

That's a classic strawman argument, based on a cherry-picked quote and deliberate omission of the points which respond to your assertion - before you even made your assertion!

Here's the complete post to which you responded, with the relevant bits emphasised so you can't miss them.

I would hope they are they type of guy that would use an appropriate tool.

• for many RF measurements that means a frequency-domain or modulation-domain instrument (a scope is time-domain)
• for amplitude shift keying (ASK), that means an "RF probe"

With one of those they could use any scope with a bandwidth that exceeds the signal bandwidth/baudrate (which has nothing to do with the RF carrier frequency).

Example RF probe: hp11096a/b. While that's only characterised to 700MHz, with modern components it would be trivial for an amateur to build a higher frequency equivalent.

And apart from that, my 21GHz spectrum analysers (plural) only cost £350 each.

4

FPGA / Re: If Lattice iCE40UltraPlus has DDR primitives like ODDR in Xilinx?

« Last post by Shell Albert on Today at 09:08:39 am »

To be honest, the motivation we chose iCE40UltraPlus is its low-power-consumption feature. We have a project powered by single core optical fiber, and a photovoltaic cell is used to convert light to electricity. Considering the ultra low power consumption of iCE40, our team leader made the ultimate decision and he allocated this job to me. ice40up5k only has 48 IO pins, including power and ground, literally the general input/output ports are less, so the hardware engineer connected a DDR SPI RAM to it with only 4 pins used. (CS, SCLK, MISO, MOSI)

but the SCLK is Double-Data-Rate, the first time I see DDR SPI.

In conclusion, if Lattice does not offer DDR primitives, I tend to use two clock domains in my design, clockA for general use, clockA*2 for operating DDR SPI.

5

Microcontrollers / Re: Attiny1606 burning out when connected to a drv8251

« Last post by pcprogrammer on Today at 09:05:47 am »

I am skeptical too. Power usage on the 3v3 rail, when drv is under load, is around 20mA. Not sure if there was some kind of problem with the voltage regulator.

Measuring the supply voltages with a scope can show noise levels, but also if there is high frequency oscillation due to the lack of proper decoupling. I have seen this happen in test circuits without decoupling and could solve it by adding a proper decoupling cap. Usually 100nF does the trick.

Replacing the LDO with an other one could have changed the dynamics of the circuit and solved the problem that way.

6

Test Equipment / Multimeter selection for production testing

« Last post by tszaboo on Today at 09:05:44 am »

I'm setting up a production line testing tool. It an in-circuit functional testing JIG, that measures a bunch of things, and makes sure that the board we ship is within specifications. There is one test that's still missing, measuring the current consumption of the DUT. The original design called for a Keysight 34465A for this. And well, it's not within the budget to buy a new one.
So I'm searching for an instrument that can do current measurements, connect to the test system with Ethernet (USB might be acceptable). I though to ask the collective brainpower of the EEVBlog forum, because you know more instruments than I do. So here are specs:
- Desktop multimeter
- Measures ~100uA with 10uA accuracy
- Measures ~2A with 1% accuracy
- Can switch between these ranges without disconnecting the DUT
- Has Ethernet and SCPI, maybe USB
- Doesn't look like a toy
- Not an absolute nightmare of software to automate

My baseline is now the Siglent SDM3045X which I think would fulfill the role. I'm basing this on no actual evidence, just a guess, having never used Siglent multimeters. Honorable mention are all the Owon multimeters that look like a toy, and the Hantek 365* that looks like the piece but doesn't have uA range. And the Keysight U2741A that's somehow even more expensive than their 6.5 digit desktop meters.

7

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

« Last post by Mechatrommer on Today at 09:05:18 am »

I would hope they are they type of guy that would use an appropriate tool.

• for many RF measurements that means a frequency-domain or modulation-domain instrument (a scope is time-domain)

with what? 30K$ fieldfox? and 5K$ probe or cables? Sometime looking at presence of carrier will help. There's diy close loop antenna probe to detect rf etc.. and with cheap item we can do relative measurement of rf power, not necessarily absolute traceable measurement. if you cant do more with less like i can i wont force you, cheers.

8

Test Equipment / Re: SDS800X HD - Issue disscusions - is it me, or the scope?

« Last post by 2N3055 on Today at 09:05:13 am »

What was also confirmed by many others are many false alarms and errors you made and then blamed scope . That is why we say a methodical approach is needed and good detailed explanations are needed.

For instance, you NEVER write what FW you are running at the time you encountered something that is suspicious behaviour or bug.

So in few weeks from now, when stuff is fixed nobody in the world will know if all the stuff you reported is still suspicious or that was some old initial FW that is not relevant anymore.

Like I said before but it fell on deaf ears.
You can stop writing about bugs, looking for them, or investigate them at this moment.
You are wasting your time (and ours if we decide to read).
There is imminent FW release being tested, as we speak.

Wait for a bit until new FW comes out.  Then start first with all the stuff that was reported in release notes that will come with it, then all the stuff that was reported and you don't see them in release notes.

This is my advice to you. You don't have to listen, of course.

You are too harsh with eTobey, I think. Yes, there have been "false alerts", but a surprising number of actual bug findings too. And this thread is titled "is it me or the scope?", so what's wrong about bringing up potential issues where one is confused and wants to ask others for help to clarify the situation?

Firmware version is 1.1.3.3. throughout -- what elese would it be for mere mortal users?   But I do agree with you that a bit more detail about the signals and settings would be helpful in many reports.

Regarding the upcoming firmware, you are quite bullish in your advice that "it's likely to change everything, you can stop looking for bugs for the time being". Have you tried with the two most recent bugs (#14 and #15) which eTobey found over the past two days, and which electronics hobbyist has added in the SDS800X HD bug thread?

I'm not to harsh with anybody. Just stating facts. 530+ posts and 4-5 bugs from him.
He had more repetitive reports and false alarms than real findings..
We have a proverb that loosely translated means "you have to bake bread before it is good to eat..".

I'm not saying all he says is wrong because he did find some real problems but he is very eager to write something so he's trigger happy. That is why I still read and answer to his posts. I took seriously (on probation) his apology post, so I approach him as someone a bit clumsy instead of malevolent.

But wrong is still wrong, facts are still facts.

As for being bullish, I'am not. Just saying.
Why waste time for detailed review of Golf8  2 weeks before Golf9 is released? It is a waste of time.

Yes, when new FW is released, list of all of reported bugs is formally invalid.

It remains as a reminder, a shortcut, what to check again in a new version.

In which case it is either not existent anymore (fixed), not fixed (not addressed, deferred for later), fixed partially (it was addressed but fix was only partially successful), or was fixed but new defects were introduced (it was addressed but by mistake some other error was introduced).

In addition to that maybe new defects could be introduced ( by regresion or in new functions added in meantime).

So any bug list lives only in that FW revision.

Any bugs in old FW found postmortem after new FW is available are either fixed already (sometimes one bug triggers a revision of part of design, that reveals some errors in common parts, so one fix fixes several bugs).  Bugs that were not fixed will be discovered in new one anyways.
So doing a work twice instead of once.

I'm not at liberty to discuss details, but can help friendly people with generalized advice not to waste their time.
As I said, not ordering anyone anything. A friendly notice.. If you don't care, your prerogative.

Best,

9

Repair / Re: HP 3457A Opto-coupler/opto-isolator replacement

« Last post by almarghi on Today at 09:02:15 am »

It depends if you mount it upside down (like me) or normal. Either way you always have to cross 2 pins on one side.
I mounted it upside down, so I crossed the supply pins on the receiver side.

10

General Technical Chat / Re: What did you buy today? Post your latest purchase!

« Last post by paulca on Today at 08:57:34 am »

here is some interesting math about the tritium keychain
https://www.gammaspectacular.com/phpBB3/viewtopic.php?t=889

the skin exposure divided by area is interesting to me. thats a big number

But if you lose a hand due to this, you always have your teeth to make up for it.

The point in reading the above that I went, "Ah... hang on a minute there."

Was here:

If 2.7mS/y is for whole body exposure to background radiation and the odd higher source like a medical x-ray maybe we can assume that the entire area of the skin is exposed to this amount on average, so we can find the average exposure of 1cm of skin as follows:

I am fairly sure it doesn't work that way.

Also the experiment is invalid without measuring the xrays where are NOT absorbed but pass straight through.

If you have a choice to eat a radioactive cookie, ALWAYS pick the gamma cookie, if that has gone, pick the xray cookie.