Help with TYWE3S flashing

Hardware
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1

Dear all,
I own an unnamed/unmodeled IR Blaster bought from Gearbest some years ago… I recently discovered that this is powered by a Tuya TYWE3S module that is “tasmotizable”. I found out, by looking at the connected pads and the traces, that is a clone of the YTF IR Bridge (YTF Universal Remote IR Controller Configuration for Tasmota).

I never flashed a ESP8266 based module before.
I read that I need an external source of power to flash the TYWE3S properly.

I am in possession of an old USB-TTL adapter just like this on Reichelt:
https://www.reichelt.com/it/it/raspberry-pi-da-usb-a-ttl-0-9-m-pl2303hx-rpi-usb-ttl-p150567.html
image

This adapter is based on an old PL2303HXA chip and has only a 5V pin (and is not compatible with newer windows oses, but I managed to find an old driver and it seems to work correctly with the RX-TX shorting test).

Is it possible to power the TYWE3S module with a step-down converter and mix its GND with GND from USB-TTL adapter?

Or I better buy a new USB-TTL adapter with a stronger 3v3 line that is able to provide the correct current to the module? What you would suggest to buy?

Thanks in advance.
Ciao
Lorenzo

2

If you have a raspberry pi or any armbian board right now, you can just use those to start flashing

3

Thank you for your reply.
Yes, I have an old Raspberry Pi model B that I recently updated to RasPi OS Debian 12 bookworm.

Is there any guide to read about this method?
TIA.
Lorenzo

4

Just found out this

It seems to be a good point to start with.
Thanks for the pointer!

5

Another question:
could I power up the entire IR blaster via the usual usb port to program the Tuya module onboard? Or I have to inject 3v3 to the corresponding pin only?
I read from guides that I should avoid powering the module with the 3v3 pin on the Raspberry Pi GPIO…

Thanks
Lorenzo

6

After some googling, I found out that the 5v GPIO pin of the Raspberry Pi receives current directly from the power supply, so I can draw more current from that pin(s). So I only need to step down that voltage to 3v3 with a buck converter, instead of using the 3v3 GPIO pin to power the TYWE3S.

Please correct me if I’m wrong!

Lorenzo

7

That’s optional
I usually just use the 3.3v pin and it was enough for the chip to boot

8

With your help @ferbulous I succeeded to flash the TYWE3S module and turn the IR Blaster in a Tasmota-powered IR Device.
To stay on the safe side, I decided to use the 5V pin with a step down converter. The ground was common for all devices in the chain and at the end I succeeded.
The only difficulty I faced was the installation of the esptool.

When I launched
pip install esptool
onto the RasPi model B I had to let it work overnight to compile the rust component “cryptography”.

After that, the backup/erasing/flashing of tasmota-ir.bin was very straightforward.

Thank you again for your advice, it was a turning point.
All the best.
Lorenzo