Re: Microcontroller (AVR) programming from smartphone

piglet wrote:

RodionGork wrote:

Hi Friends!
>
Briefly: considering ways of uploading code to microcontroller
(particularly some Atmel's AtMega - same as used for Arduino) from the smartphone.
>
In details:
>
Programming MCUs (e.g. uploading firmware into their ROM) usually happens via
some proprietary interface (using SPI in case of AVR), or UART, or JTAG.
This generally involves dedicated software on the side of computer and
some hardware (USB to UART or dedicated "serial programmer").
>
Suppose we want to be able to write simple code using mobile phone -
situation I met with my class of 15+ students with no dedicated lab having 15+ computers.
>
I tried creating a small system containing two parts: First - html
web-page with a textarea to write assembly code, built-in AVRA assembly
compiler (just compiled to javascript) - and some JS code which can
"beep" the bits of the hex-file containing firmware (via audio). Second -
bootloader for target MCU which uses ADC pin to "listen" to those beeps
via direct wire connected to 3.5 mm audio jack plugged into smartphone -
and "burn" incoming data into flash memory.
>
This works (if you are curious to try, it could be found in my github
page by same username) - however there is a sudden issue: almost half of
students use mobile phones without 3.5mm jack - as nowadays it is the era
of wireless headphones already, I missed the fact!
>
So now I'm looking for further, alternative approaches. For example:
>
- attaching microphone to ADC pin instead of wired connector; code should
be beeped out via built-in speaker of the smartphone (it would be a bit
noisy class, of course) - I actually tried, but was not yet able to come
up with signal recognition algorithm of good enough quality.
>
- blinking data with display and catching it with photo-transistor
attached to ADC or digital pin, haven't tried for it seems like bitrate
would be very low (even though we generally need to upload firmware of few dozens bytes).
>
Thus I'm open to any ideas / hints / articles on improving either of
these two approaches - or perhaps something completely different which I may have missed.
>

>
Keep your audio interface but plug it into a Bluetooth audio receiver (or
cannibilze an old Bluetooth headphone and connect your audio interface to
where the earpiece was). Then students can connect audio via Bluetooth.

Beings Bluetooth uses a packet-based protocol you need an MCU to receive
packets, no?

It's easy to use a HC-05 Bluetooth Module:
<https://arduinogetstarted.com/tutorials/arduino-bluetooth>

It's harder to DIY:
<https://hackaday.io/project/184542-i-made-my-own-audio-bluetooth-module>

Danke,

--
Don, KB7RPU, https://www.qsl.net/kb7rpu
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.