With the tubing on the sensor, next is to assemble the pieces. We'll primarily be plugging together the Feather, LPS33, and OLED screen, however you will want to attach the pieces to something, otherwise moving the tubing will move everything else around, because the other pieces are so light.
For this simple project, we will use some handy dandy nylon screws and nuts to attach the pieces together using the mounting holes. You may choose to mount them all to something else like a small piece of wood, ideally something with a bit of heft to keep it in place.
First, place a 6mm M2.5 screw through the bottom left mounting hole of the Feather.
Next, using your thumb or finger to hold it in place, put the screw through the top right mounting hole on the OLED screen. Make sure the screen is under the Feather, otherwise it won't have the clearance needed.
Finally thread a M2.5 nylon nut onto the end of the screw and tighten it down to keep it in place. When you're done it should look something like this:
Next we'll repeat the process to attach the sensor to the screen.
Place another M2.5 6mm screw through the top left mounting hole of the LPS33. Hold the screw in place with a finger or tacky putty and the put the screw through the bottom right mounting hole on the OLED.
Keep it all together by screwing your second M2.5 nylon nut onto the screw and tighten it down to keep it all together.
Similar to attaching the screen to the Feather, the order of the boards matters when attaching the sensor to the OLED. The LPS33 must be on top or you'll run into clearance issues.
Now you should have something that looks like this:
The last step is the easiest: connect the boards together using SparkFun QWIIC compatible STEMMA QT cables. As long as everything is connected, the order doesn't matter, but I found the routing below aesthetically pleasing.
Wired together it should look like this:
As assembled, everything will work just fine, however I would suggest using another one of your cable ties to hold the tubing against the USB-C cable that you will use to connect the Feather to your computer.
Simply plug the cable in and fold the tubing over against the cable and use a cable tie to hold the tubing and cable together, making sure to have a gentle bend to the tubing so the airflow isn't blocked.
Giving the tubing a bit of a twist will help curve it out of the way of the screen.
Like when you attached the tubing to the sensor, you want to hold the cable and tubing together snugly but not so hard that you squish the tubing shut (a teeny bit of squish is OK)
If you are successful, now when your dog or toddler decides to play tug of war with the tubing, it will pull on the comparatively robust cable and not the sensor. This type of connection is called strain relief and they are commonly used with things like cables that will be tugged on and moved about.