NEW Brymen Bluetooth BM787BT Multimeter

[EEVblog]

Is there a caibration manual/procedure for this meter available?

No. Brymen will only release that to authorised calibration centres.

[ian.ameline]

Got my new BM787BT, and of course measured it's power draw (Using a recently calibrated Keithley DMM6500).

Connected to my trusty E3610A power supply putting out 4.4923V (Measured at the BM787BT with a 344001A that agrees within 2 counts with the DMM6500), the BM787BT drew the following currents (Average over a minute)

Meter setting: current
ACV :    8.435 ma
DCV:     4.455 ma
DCMV   3.914 ma
Ohms    Same as DCMV  (open connectors)
Capacitance Same as DCMV (open Connectors)
mA, uA, LoZ - all around 8.9 ma (+- .01ma)

DCV+Backlight: 36.843ma
ACV + Backlight: 40.772ma

ACV+BT: 10.9ma (Connected to an IPhone 30 cm away from the meter)
DCV+BT: 7.001ma

ACV+BT+Backlight: 43.021 ma
DCV+BT+Backlight: 39.202 ma

All current measurements taken in the 100ma range on the keithley to prevent it from clicking relays as it attempts to auto-range when the BM787BT is set to DCV+BT.

So it seems like the BT module is drawing about 2.55ma when connected to a phone.
It's also interesting that the trueRMS is eating about 4ma - almost as much as the plain old DCV settting.

Using energizer lithium batteries (1200mah) this should yield about 171 hours on DCV + BT, or around 110 hours for ACV + BT.
Without BT, it would be about 269 hours on DCV, or 142 hrs on ACV. (If my fat fingers didn't slip on the calculator)

[ian.ameline]

Another very nice thing;

The iPhone app works (and connects to the BM787BT meter without any drama) when running on a M4 Macbook Pro laptop (about 30cm from the meter).

Roughly the same draw (around .1mA less)

I'll run a test over the weekend to see how long I can log data from the meter - given that both the meter and the machine talking to it are plugged in to the wall and not using batteries, it would be interesting to see if we can collect data for an extended period of time.

[ian.ameline]

Feature request;

It would be really nice if "Auto Hold" would generate a new reading that is automatically recorded by the app, instead of having to press "Hold" on the meter for each reading to be recorded. (My concern is that this change would be in the meter firmware, not the app)

Thanks.

 - Auto-Holdis a super useful feature of this meter, but seems pretty useless with the app - there seems to be no way to record a value on the app that was captured by auto-hold on the meter.

[ian.ameline]

Here is what the draw looks like over time; The Keithley is doing 30 samples per second - 1 nplc, powerline sync, auto zero - it should have 5 good digits of result. It appears that part of the BT radio is de-energized at the 5 hz sample rate of the BM787.

The BM787 is not in auto-range - the range is fixed, 60V DCV - it's being fed a 0.2 HZ sinusoidal signal. It is connected to my laptop by BT - it's about 15 feet away from the BM787. (There appears to be no apparent difference in draw if the laptop is 10 inches or 30 feet distant.)

The current draw average (6.895mA) seems quite constant, but it varies by around 3mA over a fairly short period as shown by the graphs below. The Bluetooth is not free from a power / battery life standpoint, but it's very good - I don't think it would be reasonable to expect much lower draw than what I'm measuring.

(The BM787 firmware version is t8712, and the BT version is 1.0.5)

These graphs have a 10 sample moving average filter applied - The last three are without the moving average filter (Still at 1nplc, line sync and auto zero - so 30 samples per second)





These have no filter;

[rlnd36]

Hi, I made a Windows app for the Brymen BM78xBT and thought it might be useful to some people here.

It supports real-time plotting and logging, CSV export, multiple display modes, and automatic reconnection. It also works offline and doesn’t collect any data.

Happy to hear any feedback or feature ideas.

[EEVblog]

Hi, I made a Windows app for the Brymen BM78xBT and thought it might be useful to some people here.
It supports real-time plotting and logging, CSV export, multiple display modes, and automatic reconnection. It also works offline and doesn’t collect any data.
Happy to hear any feedback or feature ideas.

https://track-base.com/Software/BM78x_Client/index.php

Awesome, thanks, added to my product page.

[papabol_24]

Hi, can't connect to the windows, says password rejected even after resetting the meter. Thanks

[rlnd36]

Hi, can't connect to the windows, says password rejected even after resetting the meter. Thanks

Hi, sorry for the late reply, and thanks for reporting this. I was able to reproduce the issue. It was a bug in the software’s Bluetooth password handling. It’s fixed now and should work correctly.

Please download the updated version from the website, or use the update button in the software, whichever is easier for you. I appreciate your help.

[papabol_24]

Thanks for the quick fix, gonna check the latest version and if all goes well im getting the full version

[KedasProbe]

looks nice
writing date to the device works (not sure if it is shown anywhere, usefulness?), write time changed it but wrongly.
improvement: add units in the stats window

About the full license can I put that on 2 PCs (also my laptop) or only 1?

Maybe you should ask an AI agent to help you make an Android version of it.

[rlnd36]

Thanks!

The full version is for one PC only at any given time, but it is transferable if needed. (just click deactivate on one device, then activate on another)

Yes, I guess this app is better in some ways than the phone app, but I have never really developed anything complex for Android. I might give it a shot.

I also plan to add more features to the PC app from time to time, like mode symbols or some form of streaming/API support so compatible software can be written with access to real-time data.

And I am always happy to hear any feature requests.

[papabol_24]

Hi, can't connect to the windows, says password rejected even after resetting the meter. Thanks

Hi, sorry for the late reply, and thanks for reporting this. I was able to reproduce the issue. It was a bug in the software’s Bluetooth password handling. It’s fixed now and should work correctly.

Please download the updated version from the website, or use the update button in the software, whichever is easier for you. I appreciate your help.

Im now on full license and im having connectivity issues / drop outs, photos attached, Thanks

[rlnd36]

Im now on full license and im having connectivity issues / drop outs, photos attached, Thanks

Thanks for reporting this, and sorry for the trouble.

I test all versions very carefully, but I was unable to reproduce this issue here. Everything works fine for me, even for hours straight without dropouts.

However, in version 1.2.1 I introduced faster Bluetooth reconnects, and maybe it was trying to detect lost connections too fast. On a weaker Bluetooth stack, this might have caused false dropouts, so I changed this in the latest version. It still has fast reconnects, just with less aggressive dropout detection.

Please try the newest version and let me know if it helps. Could you also let me know if this started only with version 1.2.1, or if it happened with previous versions too? That would be very helpful.

Also, a few versions ago I had dropout problems on one of my machines with really weak Bluetooth range, and disabling the built-in Bluetooth and using an external Bluetooth dongle solved it, so that may be worth trying if the problem continues.

Feel free to contact me here or by email if you still have problems. I’ll be happy to help.

[esa.attia]

Hi ,

Does anyone know how the BM787BT compares agains the 121GW ?

Both have bluetooth  and around about the same price range

what are the main features that  differentiates the 2 units ?


Update - I just saw the thread where someone has a massive spreadsheet doing the comparisons (https://www.eevblog.com/forum/testgear/multimeter-spreadsheet/575/). All good, this table answered my questions

https://docs.google.com/spreadsheets/d/1JB1xLWaXLOCWfANM1O_2Vgg_KKbl0wTQCi409aIV6Jg/edit?gid=195812448#gid=195812448

[EEVblog]

Does anyone know how the BM787BT compares agains the 121GW ?
Both have bluetooth  and around about the same price range
what are the main features that  differentiates the 2 units ?

Update - I just saw the thread where someone has a massive spreadsheet doing the comparisons (https://www.eevblog.com/forum/testgear/multimeter-spreadsheet/575/). All good, this table answered my questions

One difference is that the 121GW software is not being actively maintained any more. I presume the Brymen software will be, although they are yet to release the promised windows software.

[EEVblog]

Just a reminder that there is Windows software available, and it's excellent:
https://track-base.com/Software/BM78x_Client/

[dpenev]

Hi Guys,

I’ve created a simple app Voicemeter - free Android/iOS app for the Brymen BM78xBT.

It connects to the meter over Bluetooth and:
*Shows live measurements, units, and modes
*Detects stable readings and reads them aloud
*Keeps a timestamped list of recent measurements
*Lets you choose the spoken measurement resolution

I think pretty useful for example if you measure several voltages on your board
and you don’t want to keep looking away at the multimeter display.

The BM78xBT’s own Auto-HOLD function should be disabled.

Google Play: https://play.google.com/store/apps/details?id=com.voicemeter.app
The iOS version is currently awaiting App Store approval, I will share the link after this is done.

For more information please check https://rogprobe.com/voicemeter/

Bugs and ideas for new features are very welcome.
If you would like support for another Bluetooth multimeter, please let me know.

Cheers
Dimitar

[EEVblog]

I’ve created a simple app Voicemeter - free Android/iOS app for the Brymen BM78xBT.

Thanks, added to the product page.

[nomead]

Batteries failed in the one meter over night causing a disconnect. Oddly enough, the software actually saved the data.     I went ahead and installed a fresh set of AAs into my hacked battery holder.   Time for some extended testing.

I'm not sure if it's mentioned here before but there seems to be possible battery extension in works, most likely for 6 x AAAs.

[EEVblog]

I'm not sure if it's mentioned here before but there seems to be possible battery extension in works, most likely for 6 x AAAs.

Yes, Brymen mentioned they are working on this due to community feedback on the BT model.
Where did you get the image?

[EEVblog]

I can confirm that the BEP-78X is real, and I have the datasheet, but it's not released yet, they are still working on refining the production.

[EEVblog]

Brymen said I could share the datasheet

[nomead]

I'm not sure if it's mentioned here before but there seems to be possible battery extension in works, most likely for 6 x AAAs.

Yes, Brymen mentioned they are working on this due to community feedback on the BT model.
Where did you get the image?

It's listed as one of the accessories for BM78x Series on Brymen website.

[nomead]

Wow, 8kV isolation and still maintains CAT-ratings, exceptional.
3xAAAs provide the same usage time as before i suppose.