@nca78 Oh, really?! I would have guessed that the light from such "cheap LEDs from AliExpress" would be barely visible when combined with a high value resistor. I bought some assortments of leaded LEDs from China a while ago, just to have some at hand to tinker about - some of which aren't even bright enough to tell if they are lit indoors at daylight (especially green LEDs) when using a small 220R or 330R. Contrary to "branded" LEDs I've got from local distributors (probably the benefit of having an actual datasheet with specs). SMD LEDs might be a totally different thing then, regarding luminosity. Or the case size matters (smaller -> higher concentration -> tiny dot, but very bright). ... or I simply ordered garbage.

the message sending time was reduced to 10 seconds as in the debug mode. There is no difference in the dry sensor or in the water.

Forgot about this guy... Updated the project a little, the PCB now have footprints for both normal and PA+LNA modules. The old boards are still available on the github repository if needed. Even with the extra length added to the PCB with the dual footprint, it is overall still smaller than a regular non SMD NRF24L01 module.

@EddyG PCB received and tested, new version (v1.1) available here and on github.

Okay, finally got the original nrf24l01 SMD modules with the square chip visible... As exptected, things work just fine now, so the culprit of my issues was really the incompatible/fake "nrf24l01" SMD modules with the epoxy blob. If you want to use normal nrf24l01+ modules together with this smd gateway, DO NOT USE the smd module with the epoxy blob, as they won't work. Using only the fake SMD modules might work, too, but mixing the fake modules with real ones does not work.

I have been using an old(cheap) wall-to-USB power supply. I'll give it a try with a beefier supply and let you know the results I get.