A small box for the ESP-01 module with temperature/humidity sensor with possibility to connect sensors over RJ9 connector.

Main features:
- space for ESP-01 module
- additional space for prototype board PCB 1x1 inch
- 2x connector for RJ9 (616E 4P4C RJ9 Female Telephone Connector)
- place for USB-C power connector (USB Type C 2pin Connector Jack Female)
- size 34x75mm
- both PCB need to be secured by PCB holder
- possible to extend it about 1 or 2 RJ9 connectors
- it can be used for any type of sensor required up to 4 wires (temperature, humidity, relay, …)

For my solution, the original temperature sensor is dismounted from the ESP-01 module and only external sensors are connected. 
The prototype PCB can be used to add some additional features.
There is also some space in extensions boxes.