Des éléments de réponse ici :
My main question though is how long can the cables be on these sensors.
I need to run them at a minimum of about 12 meters. Is this possible?
For the TMP36 definitely not, for the DHT22 probably not.
The TMP36 is an analog sensor and this signal will take up lots of electrical noise even if the cable
is only 1 or 2 meters. You won't get a usable value with long cables even if you put some caps in
place to filter out some of the noise.
The DHT22 uses a digital protocol to transmit it's sensor data, so it's much more immune to taking
up electrical noise but for 12 meters of cable you probably need a differential signal as RS485.
One possible solution is to take an additional Arduino, put it near the sensors and connect the two
via some MAX485 chips (RS485 drivers).
Essaie de torsader tes fils de 15 mètres : est-ce que ça change ?
Sinon, la solution proposée est d'ajouter un driver RS485 (20 centimes chez Ali)