Bug: Internal Temperature Sensor displays "--" (Alientek DM40C via Bluetooth)

[o2809013]

Bug Report
I have tested the application by running the source code (main.py) directly to bypass the security flags. While the thermometer works correctly when an external thermocouple is connected, the internal sensor fails to display any data. The value remains stuck at -- on the GUI.

To Reproduce

Run the application via python main.py.

Connect to the Alientek DM40C via Bluetooth.

Observe that the external thermocouple readings work fine.

Remove the thermocouple: The display switches to and stays at -- (internal sensor reading is not captured).

Security Note (False Positive)
I scanned the provided .exe file on VirusTotal. It appears that ESET-NOD32 and other engines flag it as Python/Packed.Nuitka.AI. This confirms the detections are False Positives caused by the Nuitka packager. I will continue using the source code for now to ensure a stable testing environment.

Environment:

Device: Alientek DM40C

Connection: Bluetooth

OS: Windows 11

Execution Method: Running main.py directly

VirusTotal Link:
https://www.virustotal.com/gui/file/d93daee68388604f86e029093c1e7821455e7c9345bf82a7d855f9928398a263

[maj113]

Regarding AV false positives there's not much I can do, I'd need to buy Nuikta commercial which would

1. Maybe fix the false positive, but:
2. (most likely) Increase binary size
3. obfuscate the code

See: https://github.com/Nuitka/Nuitka?tab=readme-ov-file#windows-virus-scanners

I'd rather not obfuscate the code as that would seem more suspicious than those AV FPs, the Builds published on releases are built straight from source code by build.yml and the resulting binary is SHA256'd and automatically included on the release page so they can't be reasonably tampered with

Of course it is added as a convenience so Python doesn't need to be installed (it is embedded in the exe and this is probably what those AVs are flagging), anyone can use the script version (main.py) as long as they have a recent version of Python e.g. 3.10+ installed

Now regarding the internal temperature sensor:

it seems to work fine on my end without any issue even without a thermocouple attached or am I misinterpreting the issue, do you want it to be shown on the big display, when main reading is unavailable?

[o2809013]

I think I initially missed it because of Windows 11 scaling, since it appears quite small in the bottom-left corner.

Maybe it would be better to show the internal temperature in the main display area as well (like the thermocouple), and just add a small “INT” or “INTERNAL” label to indicate the source. This would make it more consistent and easier to notice.

[maj113]

I redesigned it a bit and used a slightly nicer layout that's more close to what the DMM does, also made the aux measurements text slightly bigger and bold:

Is this okay?

[o2809013]

Looks better, thanks!

But what I meant was slightly different — instead of showing the internal temperature as a smaller aux value, I think it would be better if it was displayed in the main area (like the thermocouple), and just have a small “INT” label to indicate the source. Like this;

Right now it’s still a bit easy to miss compared to the main reading.

[maj113]

if it was displayed in the main area

Only in the case when main isn't available?

keeping both INT and main temp on the big text label might not work nicely/be feasible due to text length, I'm keeping the right part reserved for future use (something like the measurement snapshots that the meter also supports)

I'll convert this issue into a discussion in a bit done

[StepanKoshman]

Could you please add support for the Alientek EL15 electronic load?🙏

[maj113]

Could you please add support for the Alientek EL15 electronic load?🙏

@StepanKoshman
Probably not in the near future, I don't have one to be able to reverse engineer how it talks to the app.

Looking at the app from Alientek's page it doesn't seem to support many features for the EL15 so it wouldn't take that much effort to implement but without the device in hand I can't do much

Also if you want to discuss this further I'd recommend opening a new discussion since its not related to this one

[StepanKoshman]

http://github.com/wirenboard/alientek-bt-protocol
please take a look here

P.s. A separate thread on EL15 would be very helpful, thanks!

[maj113]

P.s. A separate thread on EL15 would be very helpful, thanks!

By the way i think you can also freely create discussions too so if you want to make one for anything feel free to do so :)