Experience with Fitting External Antenna to Tuya Wifi Device for Better Signal Gain?

Has anyone successfully fitted an external antenna to a Tuya device? If so, how big is the gain?

Background: My WiFi sunblind control works great now, but at its installation location outside the reinforced concrete wall on the other side of the house, the WiFi signal is unfortunately too weak. I am considering if an external antenna on the CB2S module would help to get a connection.

I haven't tried it, but you may be interested in the Tuya documentation of, for example, CBU vs CBU-IPEX modules.
CBU, as per Tuya doc, has only onboard PCB antenna:

Quote:

Onboard PCB antenna with a gain of 2.2 dBi

https://developer.tuya.com/en/docs/iot/cbu-module-datasheet?id=Ka07pykl5dk4u
While CBU-IPEX, provides also an antenna connector:

Quote:

Support external FPC antenna, antenna gain 3.3dBi

https://developer.tuya.com/en/docs/iot/cbuipex-module-datasheet?id=Kaedsyurckrhu

However, I am not sure if an external antenna can be connected correctly to CBU without additional circuitry.

PS: That's interesting, is this a CB2S with bigger antenna?
https://developer.tuya.com/en/docs/iot/CB2S-J-module-datasheet?id=Kcu3241gzkpbh

As I read this, the circuit board arrangement in the curtain module is extremely inappropriate:

Quote:

"Antenna interference reduction

When a PCB antenna is used on a Wi-Fi module, we recommend that the module antenna is at least 15 mm away from other metal components. This can optimize the Wi-Fi performance."

I have found something. Most of it with ESP, but the board design is similar. A Tuya example is also shown.

Hinzugefügt nach 29 [Minuten]:

p.kaczmarek2 wrote:

CBU vs CBU-IPEX modules.
CBU, as per Tuya doc, has only onboard PCB antenna:

Interesting. A CBU module is installed in my door sensor, for example. The pads for the IPEX connector are easily accessible and it would be possible to solder a coax cable for an aerial directly to them. The only question is what needs to be changed in the signal path (the antenna is on pin 2 of the IC) so that the external and not the PCB antenna is used.



[EDIT]
With the CBU board, I am almost certain that you can choose between PCB and external antenna by re-soldering this component. At least that's what it looks like in the picture and my continuity measurements suggest so. Look at this datasheet







Unfortunately, my curtain module has the even smaller CB2S built in, so either I find a way to attach an external antenna to it or I make a jumper board for the jumper board and swap the module (form factor doesn't matter, there has to be an outdoor housing around anyway).

Hinzugefügt nach 46 [Minuten]:

p.kaczmarek2 wrote:

However, I am not sure if an external antenna can be connected correctly to CBU without additional circuitry.

I found the wiring of the antenna here: https://developer.tuya.com/en/docs/iot/bk7231t-cob-hardware-design-guideline?id=Ka97u6dz0h8b8#title-2-Minimal%20system%20diagram. It will probably be similar for the BK7231N.

The antenna is printed on the board. Just scrape off the protective layer and solder a several-centimeter long wire to the outside of the housing. I soldered it at the very end on the right side and the range increased by 15 meters. If you have some time, try soldering such a wire in different places of the built-in antenna. You need to hit the point where this antenna has the maximum reception point. I am very old and visually impaired. But it will be nice to benefit from the experience of forum users. I have several such devices in Tuya, but they are all at the edge of the wifi range. Regards.

Added after 9 [minutes]:

One more thing. Can Tuya devices powered by 3V batteries be powered with a slightly higher voltage, e.g. 3.3V?

Goldenar wrote:

One more thing. Can Tuya devices powered by 3V batteries be powered with a slightly higher voltage, e.g. 3.3V?

my experience so far has been that I can power 2x 1.5v battery devices with 3.3v external PSU. I've only ever powered the modules with 3.3-3.6v in fact when flashing, often in situ. From my experience so far, 3-3.6v is within the operating margin of all the components in these things. Aren't the BK chips something like 2.6-3.7.

Many things can be run at slightly higher voltage than usual but the real question is how much would that shorten their lifespan in the long run. It's hard to determine that without doing a long-term testing (for example running BK at 3.7V for 2 years).... that's why it's always recommended to use the optimal voltage chosen by manufacturer.

Goldenar wrote:

. All you have to do is scrape off the protective layer and solder a several centimetre long wire and lead it outside the housing. I soldered at the very end on the right side and the range increased by 15 metres. If you have a bit of time, try soldering such a wire in various places of the built-in antenna

.
Do you happen to have a picture? I have a ZS3L module and don't know where to solder in