EEVBlog 121GW Discussion thread

[unknownparticle]

Situation sorted!!
I had a think and realised the file hadn't been extracted and the renaming hadn't worked properly.  I renamed the thumbnail in the folder that I saved the new update to, but I didn't realise the file hadn't been extracted so wasn't actually renamed. Worked my way through that, dropped the SD into the meter, did the install key press thing, then I saw the download progress on the display bar graph!  Ta Da!!

If the manual had mentioned what the download progress should be indicated by, I would have known there was an issue with the file on the SD!

So, meter now updated, all good! And the boot loader seemed to tolerate my ignorance fine!

[ve2mrx]

I would expect the card to require Fat or Fat32 formatting, preferably done with the SD Association SD card formatter.

If your card is too large, it won't be Fat or Fat32 and the meter won't read it.

Martin

[unknownparticle]

Possibly, I actually went back to the SD card supplied with the meter, which is 8GB. Thanks.

[beanflying]

Hi,

I found it is not possible to report an issue on the store page here:
https://www.eevblog.com/product/121gw/

Hence have an issue to report.
According to the current version of the manual, the thermocouple reading cannot be calibrated.

One simple way of doing it is to use boiling/freezing water.
Capture the max temp when you put a K-type probe into your home boiler, make sure it does not touch the bottom where the heater is and you have the first point.
Water with ice would be the second one. Put water with lots of ice, wait. Make sure the probe end-tip does not touch the ice and capture the lowest value.

Is that a good idea?
Best

To some degree (no pun intended  ) there is not a huge need to try and 'calibrate' the meter with a K type thermocouple. 'Roughly Checking the Calibration' is about all you can do with your method.

Generally accepted accuracies Type K ±2.20C or ±0.75%

While the 121GW's spec is less than that Temp °C, -200 to 1350°C, K-Type, 0.1°C (resolution), ±0.5%+3°C (stated accuracy)

So inherently because of this you can not get a reading more 'accurate' or known under the spec of the meter. The Meter if it was to be calibrated on the Temperature range would more likely be done against a calibrated source instead.

[matemathieu]

To some degree (no pun intended  ) there is not a huge need to try and 'calibrate' the meter with a K type thermocouple. 'Roughly Checking the Calibration' is about all you can do with your method.

Generally accepted accuracies Type K ±2.20C or ±0.75%

While the 121GW's spec is less than that Temp °C, -200 to 1350°C, K-Type, 0.1°C (resolution), ±0.5%+3°C (stated accuracy)

So inherently because of this you can not get a reading more 'accurate' or known under the spec of the meter. The Meter if it was to be calibrated on the Temperature range would more likely be done against a calibrated source instead.

It got a 100ºC error @600ºC.
Then I checked by dipping it into boiling water and it showed 107ºC.

Then I realized it was partially due to the low battery of the unit, I changed them, and it got back to something in the specs.

[ve2mrx]

Remember that the temperature of the meter is part of the temperature reading, the K-type thermocouple measures temperature difference between both ends, not a temperature like a thermistor!

Calibrating the meter would only be for a specific probe. It's best to check the accuracy of the meter's internal temperature reading and calculate the offset the probe adds to it. Maybe do two points with the probe and derive an equation from the measurements and attach it to the probe. You would then correct the meter temperature and add the probe correction to it to get a final temperature... Or use a dedicated precision measurement system like a 4-lead platinum probe.

Martin

[JDW]

I purchased a 121GW brand new from the official store in Jan. 2023, and I then downloaded the Meteor app for my iPhone.  It works well enough via Bluetooth communication, but I wanted to compare with the official 121GW iOS app here. Sadly, it says Not Available regardless of whether I am signed in with my Apple ID for the USA or my other Apple ID for Japan.  Is it region locked to Australia (which would be crazy)?  Or is the official app totally dead on iOS for some reason?

The reason I even ask is because I dislike the Meteor app because it lacks a FREEZE/HOLD feature.  When logging data with the app via Bluetooth, I want to be able to tap the iPhone screen or a button in the app to freeze the waveform display so I can better examine it.  If I stop logging, the frustrating Meteor app dims out the waveform display, making it harder to see!  I wanted to download the official 121GW app to see if it works better than Meteor in that regard.  But again, I can't find the iOS official app anywhere now in 2023!

[EEVblog]

I purchased a 121GW brand new from the official store in Jan. 2023, and I then downloaded the Meteor app for my iPhone.  It works well enough via Bluetooth communication, but I wanted to compare with the official 121GW iOS app here. Sadly, it says Not Available regardless of whether I am signed in with my Apple ID for the USA or my other Apple ID for Japan.  Is it region locked to Australia (which would be crazy)?  Or is the official app totally dead on iOS for some reason?

The reason I even ask is because I dislike the Meteor app because it lacks a FREEZE/HOLD feature.  When logging data with the app via Bluetooth, I want to be able to tap the iPhone screen or a button in the app to freeze the waveform display so I can better examine it.  If I stop logging, the frustrating Meteor app dims out the waveform display, making it harder to see!  I wanted to download the official 121GW app to see if it works better than Meteor in that regard.  But again, I can't find the iOS official app anywhere now in 2023!

I didn't do anything with the IOS app, it hasn't changed since the original release, so AFAIK should still be available. I don't have an iPhone so I can't check.

[JDW]

I purchased a 121GW brand new from the official store in Jan. 2023, and I then downloaded the Meteor app for my iPhone.  It works well enough via Bluetooth communication, but I wanted to compare with the official 121GW iOS app here. Sadly, it says Not Available regardless of whether I am signed in with my Apple ID for the USA or my other Apple ID for Japan.  Is it region locked to Australia (which would be crazy)?  Or is the official app totally dead on iOS for some reason?

The reason I even ask is because I dislike the Meteor app because it lacks a FREEZE/HOLD feature.  When logging data with the app via Bluetooth, I want to be able to tap the iPhone screen or a button in the app to freeze the waveform display so I can better examine it.  If I stop logging, the frustrating Meteor app dims out the waveform display, making it harder to see!  I wanted to download the official 121GW app to see if it works better than Meteor in that regard.  But again, I can't find the iOS official app anywhere now in 2023!

I didn't do anything with the IOS app, it hasn't changed since the original release, so AFAIK should still be available. I don't have an iPhone so I can't check.

Well, it's not.

I searched for the original Apple app store URL and found it on Twitter, but if you click it yourself, you will discover the app is no longer available.  Please try it yourself...

https://apps.apple.com/us/app/121gw/id1396353605

I'm assuming you hired someone to create that app originally, since I found a Dave Jones post on Twitter saying "I don't use anything Apple."

https://twitter.com/eevblog/status/1013951195071721472

If so, the entity who created the app should confirm with Apple as to why the iOS version app was removed from the Apple app store, with the aim of having it reinstated.

[bicycleguy]

Before you get too excited about the original app know that the 'HOLD' feature only holds the text value.  The graph continues to scroll.

I have the app on a 2015 iphone6 with ios12.  It still works as originally.

121GW does not show up in the app store because  unfortunately apple while claiming to be environmentally sensitive has determined that this phone is too old for them to allow updates to the latest ios16.  They want users to trash their perfectly fine phones and buy new ones.

Since Seppy doesn't even own an iPhone he is not a likely candidate to update the app.  It would be nice and perhaps help sales of 121GW if Seppy posted the source code on GitHub so others could update the app.  I don't understand why Dave doesn't make it so.

[JDW]

Before you get too excited about the original app know that the 'HOLD' feature only holds the text value.  The graph continues to scroll.

I have the app on a 2015 iphone6 with ios12.  It still works as originally.

121GW does not show up in the app store because  unfortunately apple while claiming to be environmentally sensitive has determined that this phone is too old for them to allow updates to the latest ios16.  They want users to trash their perfectly fine phones and buy new ones.

Since Seppy doesn't even own an iPhone he is not a likely candidate to update the app.  It would be nice and perhaps help sales of 121GW if Seppy posted the source code on GitHub so others could update the app.  I don't understand why Dave doesn't make it so.

Well, I still have an iPhone 7, for what it's worth, and I cannot see the app even on that ancient phone!

Any app developer should support the iOS app store due to the sheer number of people out there who use the iPhone, but it is important to click your app links at least once a year to see if the app is still available.  Clearly, that hasn't been done here, and if any of you will kindly click the link in my previous post, you will see the app is not there.

Meteor is the only available app, and if it would allow us to FREEZE the screen to view logged waveforms so they won't scroll on by, then my biggest complaint will have been solved, and there perhaps would be no need for the official app.  So maybe a tie-up between Dave's developer of the official app (I don't think Dave wrote the app himself) and Meteor would be the best way to approach it.

It's easy for an Android user to flippantly say, "well, I don't use iOS, so I really don't care," but iOS is big worldwide, and some of us have never owned an Android phone, nor do we have plans to get one for the lone purpose of running the official app.

All said, the current status quo of the official app NOT being downloadable on the Apple iOS app store needs to change.

Thanks.

[EEVblog]

Since Seppy doesn't even own an iPhone he is not a likely candidate to update the app.  It would be nice and perhaps help sales of 121GW if Seppy posted the source code on GitHub so others could update the app.  I don't understand why Dave doesn't make it so.

I thought it already was, apparently not.
The Android app has been there since day 1.
https://gitlab.com/eevblog/
I'd add it but I have no idea how to upload entire directories to gitlab 

[Brumby]

121GW does not show up in the app store because  unfortunately apple while claiming to be environmentally sensitive has determined that this phone is too old for them to allow updates to the latest ios16.  They want users to trash their perfectly fine phones and buy new ones.

It could be even simpler than that.

I had the situation that an App could no longer work with a new release of an O/S as it used features that were discarded in favour of more up-to-date means - and this was an Andriod phone.  I can see Apple going the step further and culling any Apps that will not work on their current release - despite older phones being out there that would be capable of running the old App.

While this guides all Apple users into a consistent and current environment, it does squeeze out older - but still quite capable - equipment.


In defence of this approach, the overhead maintaining multiple O/S compatibility in an App is not insignificant - and is often impossible with new features only available with newer operating systems.

[JDW]

In defence of [Apple culling older apps incompatible with new iOS releases], the overhead maintaining multiple O/S compatibility in an App is not insignificant - and is often impossible with new features only available with newer operating systems.

Be that as it may, the fact remains that the smartphone APP is the killer "Logging" feature of the 121GW insofar as the app shows you a graphical waveform representation without requiring you to unscrew and open the meter to extract the SD card which in turn must be put into a computer for the purpose of seeing a TEXT-only view of logged data.  Want a visual representation of that text you extracted from the SD card?  You must make time to graph it yourself!  And after all that time-consuming work, you must put the SD card back in.  Want more data?  Wash and repeat!  Ack!  Glad the SD card is there, but man the app is so much better!

Most people who buy the 121GW, myself included, do so BECAUSE it has data logging.  If you don't need that one key feature, the BM786 is perhaps the best pick.  And when you want data logging, you want something fast, convenient, and if possible, graphical.  The 121GW offers that by way of the smartphone app.

And so, I do hope that whatever happens now will bring us a better iOS app.  Meteor isn't all that bad, but not being able to FREEZE the waveform on my iPhone's screen (without dimming) is a critically important feature that I am totally shocked and amazed that the developer of Meteor didn't consider.  It would be great if that developer could read our discussion here, as that may inspire him to improve his app, thereby making my call for the official app to be reinstated to the iOS App Store moot.

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 had hoped to get the Fuse pack too, but frustratingly, it was out of stock.  In fact, I checked just now to find it still out of stock!  Even the 121GW meter itself is often out of stock, so I snapped it up when I could.  Had I waited for the Fuse pack to get back in stock, my worry was the meter would then go out of stock.  Indeed, had I waited, I still would be waiting AND without a meter too.

By the way, selling the 121GW on Amazon (not simply on the EEVBlog store only) might be a way to give it free advertising and more exposure.  It says "Currently Unavailable" now on Amazon, despite the fact the BM786 is available there.

[EEVblog]

After spending half the day and live stream trying to do it, thesource code is now on github:
https://github.com/EEVblog/121GW-App-Apple-IOS
also gitlab:
https://gitlab.com/eevblog/eevblog-121gw-app-for-apple-ios

[EEVblog]

And so, I do hope that whatever happens now will bring us a better iOS app.  Meteor isn't all that bad, but not being able to FREEZE the waveform on my iPhone's screen (without dimming) is a critically important feature that I am totally shocked and amazed that the developer of Meteor didn't consider.  It would be great if that developer could read our discussion here, as that may inspire him to improve his app, thereby making my call for the official app to be reinstated to the iOS App Store moot.

I had no idea that app existed.
I haven't tried it yet, but maybe it's best if I just leave it to them (or others) to do this.
The source code for my version is out there now, so anyone is free to take it and update the app or make their own.
I still have absolutely no idea why my app vanished, or what's involved to get it back up.

[bicycleguy]

Thanks for the work of putting on Github.  Your effort was successful !

I was able to clone it and relatively easily get it to sort of start working on my iphone6.  Just getting it to compile and put up a window is normally half the battle.

This looks a lot more capable than the 1.7 build I have been using even though it says 1.0.5 ?

It has 17  'Deprecations',  5 from ios9 the rest from ios10 that have to be dealt with to bring it up to ios12 that I'm using.  Deprecations are functions that apple is changing or dropping that require a little work to figure out how to modify so it will run the correct new stuff.

BT comm is working but no graphing is happening.  When I get the Deprecations fixed it'll probably start working.

[JDW]

I just sent an email to Western Computational, developer of Meteor, informing them of this discussion thread and the fact the source is now on Github.  I also mentioned the inability to FREEZE a waveform during logging.

Hopefully the end result will be a better 121GW app.  It's not a significant change, so I don't see what it can't happen.  I simply lack the coding ability to do it.

[Muttley Snickers]

(snip....)
The reason I even ask is because I dislike the Meteor app because it lacks a FREEZE/HOLD feature.  When logging data with the app via Bluetooth, I want to be able to tap the iPhone screen or a button in the app to freeze the waveform display so I can better examine it.  If I stop logging, the frustrating Meteor app dims out the waveform display, making it harder to see! 

I don't own this meter or any Apple products but wondered if as an interim measure you were able to grab a screenshot on your phone whilst logging to further assess the measured data?

[JDW]

I have the following 2 questions today which are NOT app-related...

(1) Why does the backlight flash on & off for a split second each and every time I switch on my 121GW?  I see no practical reason for that. It's not like you need to TEST the backlight LEDs each time the meter is switched on.  And while it comes on too briefly to have a negative impact on the alkaline batteries, the fact remains it does draw more current in that brief split second versus the backlight not flashing on/off at all.  Can it be said that is something which should be fixed in firmware?

(2) After switching the meter on, I want to know why it takes 3 seconds before I can use it.  Sure, I see it displays the firmware version for 3 seconds.  But does the meter deliberately wait 3 seconds solely for the purpose of displaying the firmware revision?  Or would the meter take that long to become usable even if the firmware version was not displayed?  The reason I ask is because if the meter could become usable faster than 3 seconds after switch-on, that would be beneficial, and perhaps the firmware version could be looked up somewhere in Setup instead of displaying every time the meter is switched on.

[bicycleguy]

After spending half the day and live stream trying to do it, thesource code is now on github:
https://github.com/EEVblog/121GW-App-Apple-IOS
also gitlab:
https://gitlab.com/eevblog/eevblog-121gw-app-for-apple-ios

Thanks again for posting these.  After spending a full day to figure out, both seem to be for the asci encoded version of the 121GW ble protocol (from 2016 b4 the kickstarter?) so won't work.  The IOS version(don't know about android) is called 'Smart Data Logger' and appears to be the long lost version mentioned here:
https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg2314242/#msg2314242

This is a screendump of 'EEVBlog Smart Data Logger', build 1.0.5 with startup screen data.

Any thing newer?

I don't know what @JDW was talking about unless a newer version of this existed at one time.

This is a screendump of a working version of 121GW, build 1.7, loaded from app store around 2019 I have which doesn't do data logging.


I'll probably try to merge newer parsing code from somewhere around here but a newer version would save a lot of effort.

[JDW]

I don't know what @JDW was talking about unless a newer version of this existed at one time. (Attachment Link)

https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg2314242/#msg2314242

(Attachment Link)

What I was (and still am) talking about, with regards to the app, is explained clearly in my opening post on the matter here:
https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg4711112/#msg4711112

Since the 121GW has BlueTooth, it made sense for me, having purchased the 121GW new for the first time last month, to Google for "121GW app."  It was then I discovered information about the official app (which sadly no longer exists in the Apple iOS app store) and the Meteor app, which was not authored by Dave/EEVBlog.  Being curious about the iOS app (since I use iPhones only, not Android), I posted in this thread.

Based on that URL you provided, it seems that EEVBlog forum member @DavidWC is the author of the Meteor app.  Well, I did email Western Computational about the Github release.  No reply back or comment here though.

It would be nice if the iOS version could be made to work again.  I would like to try it out, especially since there doesn't seem to be a video out there showing its features.

If the Meteor app had a FREEZE button to stop the waveform without dimming the screen, the official app wouldn't matter so much to me.  I am merely saying that Meteor could use some work to make it better.  And I was also hoping to get the official app on my iPhone to see what features it offers.  But if the iOS app was only compatible with the 2016 edition of the 121GW and not the current version, then it would need a lot more work to get it back into the Apple App Store, I guess.

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.

By the way, if anyone has answers to the 2 questions I put forth in my previous post, which have nothing to do with the app or data logging, that would be great!

[EEVblog]

Thanks again for posting these.  After spending a full day to figure out, both seem to be for the asci encoded version of the 121GW ble protocol (from 2016 b4 the kickstarter?) so won't work.  The IOS version(don't know about android) is called 'Smart Data Logger' and appears to be the long lost version mentioned here:
https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg2314242/#msg2314242

This is a screendump of 'EEVBlog Smart Data Logger', build 1.0.5 with startup screen data.
(Attachment Link)
Any thing newer?

I don't know what @JDW was talking about unless a newer version of this existed at one time.

This is a screendump of a working version of 121GW, build 1.7, loaded from app store around 2019 I have which doesn't do data logging.
(Attachment Link)

The "Smart Data Logger" app was developed by KaneTest who make the meter. I had no input into that at all.
The "official" 121GW app was developed entirely in-house by my employee at the time David Ledger. I has not been maintained since he left. I do not have the software skills to update this myself, and at this stage I have no intention of finding someone else to update the apps.
The source code for the Android app and the iOS app and the protocol are entirely open source.

Again, I have no idea why the iOS app vanished from the store, we went through all the official red tape to get it approved and listed at the time.

[J-R]

(1) Why does the backlight flash on & off for a split second each and every time I switch on my 121GW?  I see no practical reason for that. It's not like you need to TEST the backlight LEDs each time the meter is switched on.  And while it comes on too briefly to have a negative impact on the alkaline batteries, the fact remains it does draw more current in that brief split second versus the backlight not flashing on/off at all.  Can it be said that is something which should be fixed in firmware?

Actually, I had a 121GW where the backlight failed.  It was a small SMD resistor that had cracked in half on the board containing the backlight LEDs (somewhat easy fix).  So having the backlight flash is a good test and that is what made me notice it.  But this may simply be what happens when power initially flows through the board.  Either way, this is just not an issue that needs to be fixed.

(2) After switching the meter on, I want to know why it takes 3 seconds before I can use it.  Sure, I see it displays the firmware version for 3 seconds.  But does the meter deliberately wait 3 seconds solely for the purpose of displaying the firmware revision?  Or would the meter take that long to become usable even if the firmware version was not displayed?  The reason I ask is because if the meter could become usable faster than 3 seconds after switch-on, that would be beneficial, and perhaps the firmware version could be looked up somewhere in Setup instead of displaying every time the meter is switched on.

A lot of DMMs display something before they are usable, for various reasons, most likely the DMM simply needs that long to start up so might as well show something on the screen.  Given how many dozens of different firmware versions the 121GW has gone through, showing it at power on is a good place for it.

[J-R]

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/
https://github.com/chlordk/121gwcli