EEVBlog 121GW Discussion thread

[EEVblog]

Why does any of this matter?  Because (1) the 121GW has BlueTooth for some good reason, right?  And (2) it's a bother to remove the blue bumper and unscrew the back case each and every time you want to access data logged to the SD card.  I'm very glad that SD card exists, but disassembly is required to use it.  No disassembly is required to use BlueTooth and a smartphone app, however!  Hence my posts on that topic.

Many products have app issues over their lifetime, it is a fact of life now.  Best to just move on.  The 121GW actually has it pretty good, with the official Android and Windows app still available and working, and recently someone put together some code to data log via Linux:
https://www.eevblog.com/forum/testgear/121gw-multimeter-command-line-data-logger-for-linux/

There is also Sigrok support:
http://sigrok.org/wiki/EEVBlog_121GW
https://github.com/chlordk/121gwcli

[EEVblog]

BTW, someone just told me the iOS code I uploaded the other day is the KaneTest one instead of the official 121GW app 
I'll have to check and correct this.

[JDW]

Many products have app issues over their lifetime, it is a fact of life now.  Best to just move on.  The 121GW actually has it pretty good, with the official Android and Windows app still available and working...

Once upon a time, most engineering software was exclusive to Windows, and there was a lot of shaming that took place when it came to engineers who preferred Apple hardware, even to the extent that many who embraced Windows called into question the engineering credentials of those who preferred the Mac.  But in recent years Apple product adoption has increased to the level that even Microchip decided to make a MacOS version of MPLAB X.  People in the engineering world are a tiny bit friendlier to Mac users, which is a nice break from the past.  And that has been great for folks like me who are Mac and iOS users exclusively when it comes to machines I used privately at home.  Even at work, I've moved my ProMate 3 from an old WinXP machine to my iMac, since MPLAB is on MacOS now. 

So when I read something is considered "pretty good" ONLY BECAUSE it has "official Android and Windows apps", I am compelled to chuckle and whisper to myself — that doesn't help me! :-)

But like I said, the Meteor app exists for iOS, and that DOES help me; and I will continue to use it, along with the SD card for data logging.  I am merely saying that if Meteor could be improved by way of adding a FREEZE button that freezes the currently logged waveform without frustratingly dimming the screen content, that would be outstanding for iOS users like myself (and I doubt I am the only one).  And, if the release of the official iOS app's source code leads to it coming back to the App store AND offering a different set of features than Meteor, all the better!

I wish to humbly that @EEVblog for having investing the time to reply and make source code publicly available, for those (other than myself) who could possibly make productive use of it, for the good of all 121GW users.

[J-R]

It should be trivial to pick up a basic Android tablet or an old PC for Windows/Linux.

One reason Windows is popular is due to the backwards compatibility.  It's not perfect, but generally speaking I can run apps from even 20+ years ago by simply double-clicking on them.

Many companies like Apple, Microsoft & Google are pushing users hard towards a combined hardware & software as a service.  Apple is the worst offender here with their proprietary silicon, as you literally do not own your hardware at all and Apple controls it fully.  Windows is not far behind with secure boot and app & device driver signing enforcement.  Android has been steadily moving core functionality into closed-source code for quite some time.

So I think it's safe to say the only users who can honestly avoid shaming these days is Linux users...

[JDW]

It should be trivial to pick up a basic Android tablet or an old PC for Windows/Linux.
...I think it's safe to say the only users who can honestly avoid shaming these days is Linux users...

Well, I as an Apple-product user shouldn't be forced to buy a Windows PC or Android anything just to use the original app for the lone purpose of seeing if it allows me to FREEZE the current waveform being logged AND if see if it dims the display, which is really the LONE problem with Meteor on iOS at the moment.  When using Meteor, the only way to stop the waveform is to stop logging altogether, which infuriatingly dims the screen and doesn't let you get a good look at the frozen waveform.

Because you are pitching Android and Windows, and because I assume you also have a 121GW, perhaps you could give data logging a test for the purpose of telling us if the original 121GW app allows us to freeze the current waveform being logged and if it keeps the waveform in clear view.  If not, the original app is no better than Meteor, and that knowledge saves one from having to buy a Windows PC or Android device.

Thanks.

[J-R]

OK, sure, I can tell you that neither the Windows nor Android apps appear to allow you to "freeze" the "waveform".  Also, I don't think I would call it a waveform, just a graph/plot.  It only updates about once per second and is cumulative.  It also continues to graph even when you press Hold (the last value is used for subsequent data points).

[JDW]

OK, sure, I can tell you that neither the Windows nor Android apps appear to allow you to "freeze" the "waveform".  Also, I don't think I would call it a waveform, just a graph/plot.  It only updates about once per second and is cumulative.  It also continues to graph even when you press Hold (the last value is used for subsequent data points).

Useful info, thanks.

When you tell the app to stop logging, does it continue to display the logged graph/plot?  If it does keep displaying it, does the app darken the display of that graph/plot?

[J-R]

The graph in the app can't be stopped, you can only reset it.  Although any time the mode/selector dial is changed such that the units change, the graph is reset.

[JDW]

The graph in the app can't be stopped, you can only reset it.  Although any time the mode/selector dial is changed such that the units change, the graph is reset.

Thanks.

In that case, I would say Meteor is superior because it allows you to stop Logging, which stops the Plot/Graph but keeps displaying it.  The main issue I have is that Meteor stupidly darkens the screen too when you stop logging.  But perhaps the developer of Meteor can fix that.  For now, after reading your feedback on the official app, it seems Meteor has an edge over the official app.

[J-R]

...For now, after reading your feedback on the official app, it seems Meteor has an edge over the official app.

Certainly that makes sense, otherwise I'm not sure why they would make it!

[Kean]

BTW, someone just told me the iOS code I uploaded the other day is the KaneTest one instead of the official 121GW app 
I'll have to check and correct this.

I took a quick look at the GitLab hosted 121GW App source code linked earlier, and it is a Visual Studio Xamarin/UWP app with targets for Windows, Android, and iOS.

I am not sure if the iOS support in there is complete, but loading it in VS2022 gave too many errors for me to deal with right now.  Maybe someone with a bit more experience can try before I get another chance.

I use VS2022 to do some cross platform (Android & Windows) dev, but not targetting iPhone.  I do have a Mac Studio where I maintain some older Objective C iPhone apps, but I'm far from an expert.

[EEVblog]

BTW, someone just told me the iOS code I uploaded the other day is the KaneTest one instead of the official 121GW app 
I'll have to check and correct this.

I took a quick look at the GitLab hosted 121GW App source code linked earlier, and it is a Visual Studio Xamarin/UWP app with targets for Windows, Android, and iOS.

I am not sure if the iOS support in there is complete, but loading it in VS2022 gave too many errors for me to deal with right now.  Maybe someone with a bit more experience can try before I get another chance.

I use VS2022 to do some cross platform (Android & Windows) dev, but not targetting iPhone.  I do have a Mac Studio where I maintain some older Objective C iPhone apps, but I'm far from an expert.

Thanks Kean. So all that live show effort I did to upload what I thought the iOS version was for nothing! 
I kinda remember now that David2 did write a cross platform Android/windows/iOS version, and that's why he only uploaded the one project.
I looked at it the other week and just saw and android directory and assumed it just the android version, d'oh.
So yes, the Gitlab version is the last final official version of all three platforms uploaded by David. Maybe I need to update the readme or something.

[Ro Max Well]

Hi all,

i just had received my 121 GW Multimeter when I stumbled over the newest commit in the gitlab for the 121GW's Multiplatform App:
User Dave added to the Readme File:

This is the latest and last official EEVblog 121GW cross-platform Visual Studio Xamarin/UWP app for Android, Windows, and Apple iOS targets.

So what does that mean?  Is the 121GW phasing out? Or is it just the App development, that is discontinued? Is there any official statement?

Best regards,
Robert

P.S.: I already posted this message to another Board on the forum, but deleted it there because it seemed upon further reflection the wrong place.

[EEVblog]

i just had received my 121 GW Multimeter when I stumbled over the newest commit in the gitlab for the 121GW's Multiplatform App:
User Dave added to the Readme File:

This is the latest and last official EEVblog 121GW cross-platform Visual Studio Xamarin/UWP app for Android, Windows, and Apple iOS targets.

So what does that mean?  Is the 121GW phasing out? Or is it just the App development, that is discontinued? Is there any official statement?

No, it's not being phased out. But the app has not been developed since David2 who wrote it left whenever the last commit date was. And I still have no plans to develop the app, that's why the source code is there.
I updated the readme file because it wasn't obvious this was a cross-platform source code.

[golftango]

Hi all,
Regarding the firmware update procedure for the 121GW.
I have read the words in the manual but am still unsure of the exact procedure.
So, do I need an additional SD card to the one installed in the meter to load the new firmware?  What capacity SD card?  There is no mention of this in the manual.
My laptop does not have an MSD card slot, so how do I install the file on the card?

I realise these questions may induce a groan from the seasoned tech vets on here but I am just not very familiar with this stuff

i'm really late to this party and i wish i'd found this meter about 3-4 meters earlier! first order of business is to update the firmware and i found i had v1.22 and when i removed the sd card i found a .bin file with a date of 2018 i believe. the v2.05 file i had was named xxxx2.05.bin and the file already there was named xxxx.bin without a version number. i saved that file off just in case but i didn't rename my xxxx2.05 file and proceeded.

it all worked up to the point where i have iap- and douun on the screen, but it's frozen. i suspect i'm going to have to go back to the card and take that version number out of the file name. but there's a dire warning about aborting the procedure but i can't see how i can do anything but since it's frozen and obviously no doing any processing and maybe that's the saving grace.

>>> later note: nevermind, that was indeed the problem. this time i got a progress bar and it finished within seconds. >>>

except for the thickness, i absolutely love the size of this meter. i got two meters before this one and they are both too huge to carry without a porter or a wheelbarrow. i very nearly got a fluke 117 or an owon b41t just for the size before i came across this one accidentally.

i'm glad i opened this one up because i found a bad thing right away. the springs at the negative ends of the batteries were sticking straight up. in fact, it was quite difficult to put the batteries in so that the springs were in the proper position--they kept trying to escape elsewhere.

/guy

[EEVblog]

except for the thickness, i absolutely love the size of this meter.

The original design was thinner and used AAA batteries. But for better battery life we decided on a thicker AA design.

[golftango]

except for the thickness, i absolutely love the size of this meter.

The original design was thinner and used AAA batteries. But for better battery life we decided on a thicker AA design.

it would be a hard decision for me if i was the designer as well. aa batteries are cheaper and more common than aaa's as well as having more capacity and that would be needed to support bluetooth, sd card r/w, and a backlight. i think you made the right decision as i'm not sure having a thinner meter would be worth giving up those advantages.

btw, the bt worked flawlessly on ios with the meteor app. i'd read there was once an ios app from you guys as well, but reading recent posts here seem to indicate it's been abandoned along with the other two platforms on the same codebase. would be great if someone would make a mac os app for it so i wouldn't have to squint at the iphone but even though many ios apps will run on the mac m1, meteor doesn't seem to be one of them.

but i do have a chromebook and an android tablet and i see there are at least two apps which support the meter, so i'll try them out for times i need a bigger display.


/guy

[JDW]

but i do have a chromebook and an android tablet and i see there are at least two apps which support the meter, so i'll try them out for times i need a bigger display.

Please let us know if Android or Windows apps allow you to set the Interval timing because Meteor does not.  Meteor sadly seems to lock the interval to a fixed 500ms/sample (approximate).  Bluetooth logging seems to ignore the meter's "ln" interval setting entirely.  That wouldn't be an issue if the app allows you to change the interval, but I see now way to do that in the Meteor app.  That's why I am curious if the Android or Windows apps do allow changing the interval, and if not, what their fixed interval is between samples.

For now, the only way to get the faster 200ms sampling speed is to long-press the MEM button and log to the SD card.  Would be great if it could be shorter, but I guess we need to keep our expectations in check.  Also bear in mind there is a limit of 600,000 samples total, regardless of your chosen "ln" setting Interval speed.

[golftango]

for now, i have no need for any logging although i will test in a couple of days after i've tested the other functions   just  in case a use case comes up. in fact, when i started meteor for the first time i was supremely annoyed that it just started logging automatically and it literally took me 20 minutes to go through every menu item and to realize that to keep it from doing that i had to set the sample size to zero.

but when i do install other versions i'll post back here as to your queries.

/guy

[JDW]

...when i started meteor for the first time i was supremely annoyed that it just started logging automatically and it literally took me 20 minutes to go through every menu item and to realize that to keep it from doing that i had to set the sample size to zero.

You had to see the "ln" sample size on the meter to zero (which means: 200ms/sample), as opposed to some setting in the Meteor app, correct?

[golftango]

i didn't set anything in the meter. the bt was literally the 2nd thing i did after updating the firmware. i'm still going through the manual and i haven't even gotten into the setup module yet. i need to do that now to get the time set--the date was ok.

just went through setup and changed a couple of things. the interval was at '0' which the manual says is 200ms/maximum. i changed this to 6 seconds for now to make calculations easier when i test it.

i connected to the meteor app and set the sample size to 100 but the app didn't seem to honor this cut off and kept counting up. when i set it back to zero it said it had logged 104 items, but by that time the counter had gone up to 170+ or so. very confusing. it was obvious the app didn't honor my 1 every 6 seconds setting, but it didn't seem to be at 200ms either. maybe 400-800ms perhaps you can tell from the timestamps:

# Source: 121GW 0
# Mode: Voltage Low Z
# Start time: 03/07/2023, 21:06:44.586 CST
Timestamp, Elapsed time (s), Value, Units
21:07:37.536, 52.950, 0, V
21:07:38.048, 53.462, 0, V
21:07:39.036, 54.450, 0, V
21:07:39.547, 54.960, 0, V
21:07:40.056, 55.470, 0, V
21:07:40.535, 55.949, 0, V

/guy

[J-R]

Has the official ACV calibration procedure been discovered/published?  I couldn't find it.  I experimented with this and it seems the ACV calibration procedure as I understand it is not correct.  If you perform the 10% offset and full-scale calibration at a specific frequency, then the DMM is completely out of whack at other frequencies and I had to restore the previous calibration data.  Looking at the Kane555 calibration procedure, it seems possible the frequency calibration needs to be performed 3 times at various frequencies after the ACV calibration, but this is not clear, nor are the frequencies for the 121GW (the Kane 555 lists 60Hz, 10kHz and 100kHz).

[JDW]

21:07:37.536, 52.950, 0, V
21:07:38.048, 53.462, 0, V
21:07:39.036, 54.450, 0, V
21:07:39.547, 54.960, 0, V
21:07:40.056, 55.470, 0, V
21:07:40.535, 55.949, 0, V

Similar timestamps as the Meteor app on my iPhone 7 generates.  I assumed the 3 digits at the far right of each time stamp to be milliseconds, so: 1000ms - 536 + 48 = 512ms, 1000ms - 48 + 36  = 988ms, and so on.  It's certainly not a stable sampling speed.  Maybe that is the only sampling speed the BlueTooth module of the 121GW can send data at?  But based on the Meteor app settings, it seems you can store up to 1 million samples.

[JDW]

Just to let everyone know, the reason for all this discussion is because I am doing prep work for a YouTube video review of the 121GW.  It was not given to me.  I purchased it new at the end of January this year, direct from the EEVBlog store.

I just made my 121GW review video public here...

https://youtu.be/1iqURp-NsdM

Thanks to Dave and others who kindly offered me feedback in this forum over the last couple weeks, which helped in the video creation.

[EEVblog]

I just made my 121GW review video public here...
https://youtu.be/1iqURp-NsdM

Took me a minute to realise you didn't have a green screen here!
Your lighting is amazing, what are you using? Do you have a studio tour video?