Bluetooth module with unusual pinout

rjenkinsgb said:

There are literally hundreds, if not thousands, of different mass-produced Bluetooth modules.
Digikey alone list over 700 lines.

Many that are sold as pinned modules with supposedly the same type number (like HC-05, HC-06 etc.) have totally different surface mount sub-modules.

I bought about ten different types last year, tying to get some specific surface mount modules.
They were all advertised as the real thing and with photos of the genuine Wavesen sub-module - and they were all different fakes with different pinouts to the real one.

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...and what do you think? what i'm trying to do will it work or not?

after ChrisP58 reply i think i'm looking at a UART communication having
current limiting resistors in series so it needs one of these little PCBs
HM or JDY type, wired to the corresponding pins.

kinda success!

soldering a bluetooth module seems it gets autoconfigured and i didn't had to do anything else!
i could see the SSID although it had an "=" before the broadcast name which as far as i know it
shouldn't exist, also i've noticed the LED which is connected to the footprint's pin, its always on
and turns off when you're trying to connect, which shouldn't happen that way..

other than that, no matter what app i've tried none can receive data, so i don't know...
what i am doing wrong?


any ideas?

On youtube and all over internet you can find people playing with bluetooth modules especially people who are on arduino projects.. but since nobody really wants to help me out with my matter here, i had to find answers by my self and offer them in case somebody does similar things and needs these details for help.


The weird "=" on the SSID i was asking about on a previous post its because the microcontroller tries to configure the bt module so it sends "AT+NAME=..." but the bt module i've attached JDY-24M expects the AT command maybe in an non standard way (without "=") so it perceives it as part of the SSID, which means there's compatibility issue.

Also ive noticed the microcontroller sends repeatidly the" AT+NAME" command i guess until it receives an OK so then to pass to the next configuration command and probably it does that configuration every time the μC initializes.

i haven't gone any further than that.. but for somebody experinced with microcontrollers and the use of such modules was it that hard to say a word on this thread?

You never responded to the request for full photos of the PCB when asked, when I was trying to help find the original type; I spent hours on that.

You then say you "soldered" a bluetooth module - but give no clues as to what module or what chipset etc., so again no one has anything for comparison or reference.

If you don't provide full info and leave people guessing, it makes it hard to maintain any enthusiasm to assist.

rjenkinsgb said:

You never responded to the request for full photos of the PCB when asked, when I was trying to help find the original type; I spent hours on that.

You then say you "soldered" a bluetooth module - but give no clues as to what module or what chipset etc., so again no one has anything for comparison or reference.

If you don't provide full info and leave people guessing, it makes it hard to maintain any enthusiasm to assist.

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hi thanks for your reply.

when you asked for photos i explained i couldn't provide more because re-opening it means
i damage the adhesive just to take a shot and close it back and also i can't keep it all the time
open until the work is done, because it is used almost everyday to move around!!

now that i am in a good point with all this..do you think you can boost my try??

i guess JDY-24M is not suitable due to the AT command syntax it expects...right?

The common HC-05 module uses the NAME= style command
(Just beware the thousands of clones; try and get a real Wavesen, that has the HC logo).

rjenkinsgb said:

The common HC-05 module uses the NAME= style command
(Just beware the thousands of clones; try and get a real Wavesen, that has the HC logo).

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ok i was thinking i should get a new one.. just i needed a confirmation about it
in case there is no workaround, by the way i'm no expert, not even studied
electronics! i'm on computer science. electronics it's like a hobby for me.

also i want to ask, i can see the microcontroller's RX pin is always high (3.3V)
is that normal when it's not receiving anything?

because i was asked if i could probe the pins with an oscilloscope or logic analyzer
to see if there's any activity and i said i can't... finally i've found a way to do and the
results are in the photos, named TX, RX

whiz115 said:

also i want to ask, i can see the microcontroller's RX pin is always high (3.3V)
is that normal when it's not receiving anything?

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Yes, at the MCU side of things, the idle state for normal serial data is high

When used with RS232 driver and receiver ICs for COM ports, the data is inverted 2wice through both the driver and receiver, so the idle on an RS232 port is negative.

The transmit data looks good, timing-wise, but the voltage levels seem odd - it should be changing from near 0V to near V+, but according to that image, the low level is over 1.5V?

Are you sure you have TX and RX the right way around? Some things, the majority, are labelled for each device's own signals (so need crossing), some with what they expect to connect to them, so straight through..

Also, what is the time per division on that image, so the baud rate can be calculated? If that does not match what the BT module is expecting, nothing will get through.

rjenkinsgb said:

Yes, at the MCU side of things, the idle state for normal serial data is high

When used with RS232 driver and receiver ICs for COM ports, the data is inverted 2wice through both the driver and receiver, so the idle on an RS232 port is negative.

The transmit data looks good, timing-wise, but the voltage levels seem odd - it should be changing from near 0V to near V+, but according to that image, the low level is over 1.5V?

Are you sure you have TX and RX the right way around? Some things, the majority, are labelled for each device's own signals (so need crossing), some with what they expect to connect to them, so straight through..

Also, what is the time per division on that image, so the baud rate can be calculated? If that does not match what the BT module is expecting, nothing will get through.

Click to expand...

this is not a normal scope so don't pay much attention to the numbers... it is called Scoppy
using a Raspberry pi pico, that's all i could do when i was asked if i can probe the board, though
maybe my setup is wrong... it uses a resistor divider from 3V3 to GND to create the ground
probe and a GPIO reads the input signal.


by the way...i wonder is there a fast way i decode the bit stream seen in the photo?
i mean i know what the TX pin initially sends but it could be useful if in some point
i can't have a serial monitor connected.

P.S time per division it says 900uS.

whiz115 said:

time per division it says 900uS.

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OK, the scope timing may be a bit off, but it looks like its 9600 baud, if any standard speed.

You should just be able to monitor it with any serial terminal program, using a 5V (not RS232) USB serial adapter, or add a CMOS inverter and it should work with a PC or laptop RS232 port, with a very short cable.

(I usually use "Realterm").

rjenkinsgb said:

OK, the scope timing may be a bit off, but it looks like its 9600 baud, if any standard speed.

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i haven't checked the speed, but since the bt module gets a SSID i guess the baud rate matches.
but probably something happens after that so the configuration is not complete.

i haven't opened it lately to check more details...as i said there's adhesive which i might
need to replace in case it gets ruined.

rjenkinsgb said:

The common HC-05 module uses the NAME= style command
(Just beware the thousands of clones; try and get a real Wavesen, that has the HC logo).

Click to expand...

Hi

i've got the HC-05 and its not suitable either..first of all you can't disable the password, then it needs to hold down a button while it is powered, so it can go into AT command mode or wire its ENABLE/KEY pin to 3V3 and send the commands at 38400 baud rate and after configuring you need to return to normal mode! but the MCU does the configuration every time it is powered and wont go beyond if it doesnt receive its OKs!! maybe i should have looked at the datasheet first?..

i wasted so much time and money for all this project (12 EUR) but the functions the bt could offer are so important!! or else you cant lock/unlock, or know total mileage (so you can know when to do some simple service it needs) or having real time power consumption indication which is important even to diagnose motor mulfunctions!!

bt is so important and its missing.

whiz115 said:

Hi

i've got the HC-05 and its not suitable either.. it needs to hold down a button while it is powered, so it can go into AT command mode or wire its ENABLE/KEY pin to 3V3 and then after configuring you need to return to normal mode! but the MCU does the configuration every time it is powered and wont go beyond if it doesnt receive its OKs!! maybe i should have looked at the datasheet first?..

i wasted so much time and money for all this project (12 EUR) but the functions the bt could offer are so important!! or else you cant lock/unlock, or know total mileage (so you can know when to do some simple service it needs) or having real time power consumption indication which is important even to diagnose motor mulfunctions!!

bt is so important and its missing.

Click to expand...

You should have bought the more expensive model with BT then - it's quite possible that the module is deliberately different to all others, to stop people doing what you're trying to do.

Nigel Goodwin said:

You should have bought the more expensive model with BT then - it's quite possible that the module is deliberately different to all others, to stop people doing what you're trying to do.

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no! it's the latest model (supposingly with more advanced specs) and it's weird situation
because previous models have the bt function.

the money i've spend it's 1/3 the price for the meter board which includes the bt function.
costed so much because i initialy bought the JDY-24M then the HC-05 and a serial
to usb cable so i can troubleshot things.

i appreciate you guys said a word on this thread, though i was expecting more since
what i was trying to do it's not something specialized, mostly has to do with bt and MCU
connectivity which is so common subject.

whiz115 said:

no! it's the latest model (supposingly with more advanced specs) and it's weird situation
because previous models have the bt function.

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It's known as 'cost improvement' in the trade.

whiz115 said:

the money i've spend it's 1/3 the price for the meter board which includes the bt function.
costed so much because i initialy bought the JDY-24M then the HC-05 and a serial
to usb cable so i can troubleshot things.

i appreciate you guys said a word on this thread, though i was expecting more since
what i was trying to do it's not something specialized, mostly has to do with bt and MCU
connectivity which is so common subject.

Click to expand...

You're asking for something pretty specialised, and providing effectively no information.

Nigel Goodwin said:

You're asking for something pretty specialised, and providing effectively no information.

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every detail needed is here #17 #23 #27

i hope it can be useful to somebody else and save time and efford
by knowing things in advance.

whiz115 said:

every detail needed is here #17 #23 #27

i hope it can be useful to somebody else and save time and efford
by knowing things in advance.

Click to expand...

No where does it even mention what IC the board supports, so not much help at all.

As already suggested, connect it to an FTDI converter and to a terminal program on your PC, see what data it's sending.

However, as the BT is most likely programmable, it may well be programmed in acompletely differtent way to any available modules?.

Is there an image search function in Google or some other utility you
could use the pic to look for a match ? Some utility that would look
for a high image correlation factor.

Just wondering....


Regards, Dana.

PS Maybe this - https://support.google.com/websearch/answer/1325808?hl=en&co=GENIE.Platform=Desktop

Nigel Goodwin said:

No where does it even mention what IC the board supports, so not much help at all.

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hey! Nigel i dont know to what you are reffering to by saying IC, but if you talk about the bt IC, if i knew what
the board supports i wouldnt be here, though you got pretty much anything you need to know so you
can help!

Nigel Goodwin said:

As already suggested, connect it to an FTDI converter and to a terminal program on your PC, see what data it's sending.

Click to expand...

i understand it is borring to read every single post and i know you got a forum to run, so you can't pay
close attention to every post since some might be useless, but i already did what you'are saying and
it was mentioned earlier. I even got a uart to usb cable, other than using a scope!

Nigel Goodwin said:

However, as the BT is most likely programmable, it may well be programmed in acompletely differtent way to any available modules?.

Click to expand...

i explained how the original bt module probably works, the MCU seems it configures it every time
via AT comnands after power up, the first command it sends its the AT+NAME=... and it repeats that
i guess until it receives an OK, so it can go to next configuration.

look i've spent time+money going to get the modules (12 EUR to local stores for modules that cost $1,5-2
each on Ebay and Aliexpress) and also effort to put things together and the result was "close but no cigar"
as you might say in your country

so i shouldnt also feel bad that i received few guidance because i wasnt clear.

and no! this is simple has nothing complicated as i said earlier i haven't even studied electronics, im on
computer science, so if i can do what i did to get all the above mentioned results, so then for somebody
who is on electronics and MCU programming its simple thing!



Nevermind, i'm glad even for the slightest interest from anyone posted here and as i said before, i hope these
details can be useful and save time for any other who might interested on something similar.