The design is 4 parts, 3D printed to enclose the electronics and mount the sensors

The parts are printed using Markforged White Nylon. Parts are tapped and screwed together with #4-40 hardware. 

Sensirion provides a STEP file of the sensor so I created a split clamp design and subtracted the sensor from the clamp for a solid fit.

I had a test board for the Olimex ESP32-POE-ISO on hand, so used that to connect to OLED and UART with a MAX 3232 dual RS232 transceivers. The board has support for CANBUS, but that was for a separate project and not used here. 

4 wires to the sensor, 5V, GND, SDA & SCL. I had limited colors so green is 5V, black is ground and the 2 x blue are i2c. 

The wires come from under the Olimex. Taped to side of housing. I had a 2nd olimex with an external antenna, so had to pop in a hole for the antenna mount. Design works with on-board antenna normally. Routing the antenna wire is a bit tight. 

Here with the OshPark test board I had on hand. 

This is device #1, with the ESP32 with onboard antenna, which sticks thru a slot in the housing. 

The sensor is wired directly to the pins on top of my test board.  

• BLK - Gnd
• GRN - +5VDC
• BLUE # 1 - SDA GPIO2 
• BLUE # 2 - SCL GPIO15

Eagle file for this board on Github.