DMM Voltcraft VC871

[RefuCire]

Hello,

as I shortly became a new owner of the above mentioned Voltcraft VC871 with Bluetooth functionality, it didn't take long, to come across this really nice project.

I didn't achieve to connect my DMM with the app and get a meaningfull reading with any of the existing connection options. I wonder, if it would be possible to support the Voltcraft in your app and what i could possibly contribute?

I include the elsewhere mentioned files that where created during connection attempts:
log-2025-09-24.txt
uuids.txt

Thanks in advance and many geetings,

Eric

[webspiderteam]

Sorry for my late answer. İ just see it. Wecan try it. let me research if i can found anything. if i cant found anything for decode protocol we need to wor together to decode but i thin we can do it.

[FireBird3314]

Apart from the 16-bit overflow and the negative sign, all other functions seem to be working great.

[webspiderteam]

The value is shown correctly until 32767 where it then overflows to negative numbers. E.g. 3,2767V is ok while 3,2768 is shown as -0,0000. In contrast negative values are not shown with a negative sign.

fixed this but not added negative sign yet because the logs that i had 128 also showing without negatives. lets test more to be sure about it. here fixed version
Debug.zip

[FireBird3314]

Great, the 60000 counts are now shown correctly. And here is a sample for -1,0054V

{36, 0, 240, 70, 39, 128, 161, 9, 240, 70, 39, 128, 5, 0, 0}

[webspiderteam]

o i added negative sign as you said. lets test this lie that we will find out anyway :)
Debug.zip

[FireBird3314]

Everything looks fine for me. Positive and negative numbers are shown as on the meter, the lie is true. Thanks for the great work.

As promised, I’ll investigate into the special bits and report what I could find out.

[webspiderteam]

sorry its not "lie" its "like" my keybord has problems some keys not working and one of them is my k button.

possible bits that could have is rel symbol, min and max and also hold indicator and battery indicator.

[webspiderteam]

then i have to debug over code to find where error accurs. but i cant do it with out device. Do you have experience with c#

[FireBird3314]

I can read it but I’m not sure I could modify and compile it. What I usually do in this situations is to put several Windows OutputDebugString() functions in places where the fault may appear. In that case I can run the test and tell you which strings did appear.

[webspiderteam]

do ypu have free time right now? and do you have discord?

[FireBird3314]

Yes, we can give it a try. And Discord is available.

[webspiderteam]

my discord : webspiderteam_71418