The choice of MOSFET can be tricky. Seems that irlz44n was discontinued so you may need to find one adapted to the voltage and current you want to handle.
In all the cases you need to get a logic MOSFET too, meaning that they are fully open usually around 1 to 3V.
Also I'm sort of confused as it seems to me that L7812CV is a Voltage regulator, not a MOSFET. So if you are actually using that in the MOSFET spot it will definitively not work.
Especially if you are handling high current or voltage I would recommend using one from a reputable source for your MOSFET, I recently switched from mouser / digikey / aliexpress to mostly use http://www.arrow.com as you get free regular shipping, event if you order a couple of components (no affiliation to them whatsoever).
I am still using several temp/hum sensor and they are running great I also have just added code and pictures for my newly build light sensor (using an LDR).
I see a lot of "!TSF" and "NACK" which seems to be radio communication problems.
That's MySensors related and can be related to many things, from soldering problem to power / capacitor issues.
In MY_DEBUG mode you should see your temp/hum printed on serial every ~15s so there is something wrong there, either wiring or a code issue.
Ty with the example included with the library "i2c_SI7021.h", without any MySensors related stuff, to see if your sensor is detected. You should see temp/hum on the serial.
To provide a large enough pulse to drive the ceramic transducer , you need a lot of energy, so they pump up the 5v with an inductor/transformer to provide a high voltage pulse. This is 60v or more…
The more Energy you produce the farther the pulse will travel….
Everything thing else on the board run at 3.3 to 5V.
Add a large Capacitor of 100 µF are so between the 5v and ground on the device, this may clean up your problem.. Some CPU modules just can’t supply enough current quick enough that’s needed when the pulse is triggered.
These are very inexpensive device, we’re luck to see them work at 1/2 the spec range.
i use the simplest boxes that you find,that suface mount with 4 screws and ruber on door.
But be carefull with wall mount screws. if you drill the back of the box ,water come in beind this box. so this ones,the scrfew holes are outside the encosure an box is sealed...
another tip is drill on bottom for pass cables but put some neutral silicone. hot glue let water come in with time because expansion coeficient is diferent that the plastic box and open gaps
