Uni-T UT61E bluetooth modification

[Steps]

I am going to add bluetooth module to Uni-T UT61E to connect it to PC to virtual RS-232.
I guess to install HM-10 bluetooth module due to low consumption, it is possible to supplay it from internal battery and it can be located internally (I am not sure does it have SPP and does it have to have it). Others need additional battery. Is it good idea?
So, we do not need optical isolation with bluetooth module due to we will have bluetooth isolation. Can anybody say is it possible to connect bluetooth module to RX by other way like it described in  http://blog.avrnoob.com/2014/03/uni-t-ut61e-rs232-serial-interface.html  by Anton Veretenenko?
Please point the place on the ut61e diagram where in is possible to get RX signal to HM-10 bluetooth module. Or we need transistor invertor due to UT61E sends inverted serial signal to its IR led?

[Steps]

I have an idea to connect BT module to pin 123 directly (see attached picture, point A) thru inverter (part of diagram - pic.2) with n-channel mosfet 2N7000.
Is it right?

[michaeliv]

I have an idea to connect BT module to pin 123 directly (see attached picture, point A) thru inverter (part of diagram - pic.2) with n-channel mosfet 2N7000.
Is it right?

Hi, I'm not very experienced with bluetooth modules so take this as something for you to investigate rather than a definitive answer.
It's not very clear what you're schematic would look like, maybe try to draw it instead of describing it.
You need a microcontroller in between the UNI-T and the bluetooth module. Even though they're both RS232 it doesn't mean that you can just hook them up together. You need a micro that would take in the raw RS232 output of the UNI-T and wrap it in commands that the bluetooth module would understand.
Basically the bluetooth module can't make any sense of the UNI-T's output.
See here for a tutorial on what the bluetooth module is expecting : youtube.com/watch?v=UNETjvmmQx4
Add a micro that would convert the UNI-T output into the compatible output.

[leon010203]

Made by this instruction. Everything works, but windows 10 does not see the com port of this module

[wasyoungonce]

I think its MS not handling Btstack com port values or non common name values in registry.  Been doing this same problem since XP on BT RS232 wireless control of telescope stuff I did.

https://answers.microsoft.com/en-us/windows/forum/windows_10-hardware-winpc/bluetooth-stack-inserts-invalid-com-port-names/ff68fac4-62b0-4b3a-b83a-0c8b1712adf8

You can edit the registry to fix it but have to do it it each boot.  You can write batch or handler files to auto fix.  Others greater than me did this for me.

[Rick Law]

Made by this instruction. Everything works, but windows 10 does not see the com port of this module

Don't miss what Michael said here:

...
It's not very clear what you're schematic would look like, maybe try to draw it instead of describing it.
You need a microcontroller in between the UNI-T and the bluetooth module. Even though they're both RS232 it doesn't mean that you can just hook them up together. You need a micro that would take in the raw RS232 output of the UNI-T and wrap it in commands that the bluetooth module would understand.
Basically the bluetooth module can't make any sense of the UNI-T's output.
...

I did some experimentation with the UT61E+HC5 blue tooth module a couple of years back.  I assume the issue would be the same with the HM10 you are attempting.

With the HC5 blue tooth, you need more than the Windows side to cooperate.  The blue tooth module itself needs to do it's part.  Hardware (circuits) alone is not going to do it.  UT61E is not capable of sending anything like pairing or initialization sequence to the blue tooth module.  You have to work that in to your set up.

With the HC5, I can hook it up to the UniT cable's RS232 relatively easily (via dividers).  But, I needed an additional TTL RX/TX input into the HC5, to first tell it to do 19200,n,8,1, set password, and to do pairing.  Only then would another blue-tooth device such as the one in Windows find and pair with the HC5 to receive stuff from the UT61E.

Granted, you can setup your HC5 so that the defaults are right and the pairing already done.  But when you want it to pair with another Windows machine or make any setup changes to your module, you need to hook up the alternate TTL input to the module again.  Eventually, my setup became UT61E->Arduino Nano->HC05, no longer simple and needs an extra power plug to power the Arduino+HC5.

In my case, it is that complication and the rare lost of communication due to other devices near by (such as moving my desk lamp too close) that prevented me in using BT.  I didn't like the potential of loosing a night of work if I happen to put some other devices too close while logging.

I must say, while I ended up not using it, it was fun getting it to work.

[-Jake-]

The HC-05 is an old Bluetooth 2.0 module, newer Bluetooth 4.0 modules (like the HM-10) do not require pairing, they can just broadcast the data and other devices can subscribe. So it does not need special sequences after initial baudrate setup. Also loosing the connection for a few seconds is no problem, it will resume after that.
A downside with BLE 4.0 is that there is no real standard for serial ports anymore, so you need some software to receive the data. Unfortunately there is nothing for Windows so far that does this (at least nothing that i know of).
For Linux i wrote my own scripts, also documented in this blog post.
For Android i wrote an app, an overview is here. I have recently published 2 updates, 1.1 and 1.2 with a several new features. It is completly open source on Github. If someone wants to use it it is also availible on the Google Play Store.
Since there is a WebBluetooth API it would be probably possible to make a cross platform (Windows, macOS, Linux) application with Electron, NW.js or even running in a browser. Maybe i try that in the future, if someone wants to look into that or would be interested in developing this together, let me know. 

[Rick Law]

The HC-05 is an old Bluetooth 2.0 module, newer Bluetooth 4.0 modules (like the HM-10) do not require pairing, they can just broadcast the data and other devices can subscribe. So it does not need special sequences after initial baudrate setup. Also loosing the connection for a few seconds is no problem, it will resume after that.
A downside with BLE 4.0 is that there is no real standard for serial ports anymore, so you need some software to receive the data.
...
...

Ah ha, I didn't know that.  Glad you shared that knowledge - I learned something new.

I should get one of those for experimentation.  As to the open broadcast part, I am not sure I like that but experimentation will tell.