Bluetooth file transfer

Thread Starter

Ian0

Joined Aug 7, 2020
9,502
I know it is possible to transfer files by Bluetooth.
I'm trying to find out if it is possible to send files to a computer using the HC-05 module, or whether the HC-05 module is simply a "RS-232 replacement" device.
 

boostbuck

Joined Oct 5, 2017
492
I believe the file transfer will reside at a higher level than the HC-05. It is only a form of serial channel, an RS232 replacement as you say.

"The HC-05 is designed to be a transparent TX/RX serial pipeline which allows devices to communicate over serial as they would through a wired connection. The is made possible by the Bluetooth software stack that is onboard the HC-05 module"
 

boostbuck

Joined Oct 5, 2017
492
It seems you are looking for a hardware module that will offer Bluetooth FTP profile to your sending device. There may be such modules but I don't know of them - it would have to be cognisant in some way of your sending device's file system.

What are the files being sent from?
 

Thread Starter

Ian0

Joined Aug 7, 2020
9,502
It‘s part of a wider question (perhaps I should start another thread)
I have a little data-logger, which makes a csv file which is 192k bytes.
What I would like to achieve is for that .csv file to appear on a computer so that it can be opened in excel.
Currently, the little data logger has a SD card slot, and it works adequately, but I’d like some transport method that works well!
 

LesJones

Joined Jan 8, 2017
4,172
What interfaces does the data logger have ? (Other than the SD card.) If it has Bluetooth then it can communicate with the bluetooth interface on the computer.

Les.
 

Thread Starter

Ian0

Joined Aug 7, 2020
9,502
At the moment it just has the SD card. I’m thinking about how to improve it. Nothing is ruled out, apart from the time it would take me to learn how to do it. The processor has a good selection of peripherals - (including USB, but I’ve not tackled USB before).
I need to get it on the computer as a file, not a bunch of numbers in a terminal window.
 

MrChips

Joined Oct 2, 2009
30,488
I am using HC-05 for my ProbeScope project. Yes, it is using UART protocol.
At 460800 baud, one byte takes 20μs (approx.).
200kB will take 4 seconds. You can capture the data and write it to a file.
 

LesJones

Joined Jan 8, 2017
4,172
Can you give us some details of the data logger ? Is this a comercial product or is it your own design. ?
If it is your design can you modify the software to output the data to a serial port ? If so then an HC-05 can send this to a PC that has a bluetooth option. I have done this using a terminal emulator program that has the option to save the received character string to a file. (I used Keaterm but that will not work on anything later than XP.)

Les.
 

Thread Starter

Ian0

Joined Aug 7, 2020
9,502
It’s my own design, but I want it as a file, not a bunch of data in a terminal window.
I’m abandoning this idea, as Bluetooth file transfer seems to be somethin that Windows and Linux does, and Apple doesn’t.
My processor* has a USB interface, I’m exploring whether it can write files to a USB memory stick and whether there might be an API which does the job for me.

*Renesas RA4M1. (Renesas is good at technical support, so they will tell me, but any relevant information from AAC members would be appreciated)
 

Ya’akov

Joined Jan 27, 2019
8,973
Have you considered Wi-Fi, which has other possible utility and offers trivial file transfer? (e.g.: HTTP, for which there must certainly be a library available to you.)
 

Ya’akov

Joined Jan 27, 2019
8,973
To expand slightly:

One cheap way to do this is using an ESP8266 which would also provide the possibility of things like remote restart and console, and watchdog (off the top of my head) as well as the Wi-Fi connectivity and readily available libraries and simple UART interface to your main MCU.
 

Thread Starter

Ian0

Joined Aug 7, 2020
9,502
Have you considered Wi-Fi, which has other possible utility and offers trivial file transfer? (e.g.: HTTP, for which there must certainly be a library available to you.)
It might work, although it requires that it be in the vicinity of a wi-fi router and to be informed of the name of said router and its password, or for it to act as the router in which case one has to go into the computer wifi settings in order to log on to it. The latter is the method Victron uses on its products.
 

Ya’akov

Joined Jan 27, 2019
8,973
It might work, although it requires that it be in the vicinity of a wi-fi router and to be informed of the name of said router and its password, or for it to act as the router in which case one has to go into the computer wifi settings in order to log on to it. The latter is the method Victron uses on its products.
Yes, I would default to an AP mode solution (its own network). There are examples of configurations that will allow setting the board to try to connect to a network but if it fails, it falls back to being an AP itself. If you have a display, you can show information on connecting—including a password which could change on reboot, or demand, etc.
 

strantor

Joined Oct 3, 2010
6,778
Whether you use Bluetooth, USB, RS232, WiFi, other, there is a bunch of data being transferred from one device to another, and if you look at it through a terminal window, you'll just see a bunch of data in a terminal window. Alternatively if you make an app on the receiving end to perform error checking, parse the data, and save it to a file, then it will appear as files being gracefully transported through air or copper. You can achieve your goal even if your device is emulating RS232 over Bluetooth. I think you are placing an unnecessary constraint on RS232, limiting it to "just a bunch of data in a terminal window."
 
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