Air quality sensor SEN5x MH-Z19 SSD1327

Air quality sensor SEN5x MH-Z19 SSD1327
 

Hello;
 

I would like to present my take on air quality sensor made out of:

• ESP32 board 
• SEN55 - PM/NOx/VOC sensor
• MH-Z19 - CO2 sensor
• SSD1327 - display

Chassis will require :

Filaments

• Geetech marble PLA
• FiberFlex 30D (TPE TPU)

Non printable:

•  6x2 mm magnets - x8
• 3 mm screws about 10 mm long - x5
• 3 mm inserts - x5
• “computer mesh” on Aliexpress
• USB-C socket
• parts mentioned at the beginning.

There are 3 parts and 3 sealings 

• bottom - that has an additional wall compared to the middle one; 
• middle - that holds all electrical components;
• top - that has no walls.

Assembly:

• place inserts and magnets mind polarity
• cut down one strip of mesh about 48mm x 450mm and push it into the bottom part. 
  • It may require pulling it with something pointy from the other side between the honeycomb lattice - especially when going through corners. 
  • If it covers honeycomb lattice from top to bottom You are good if not adjust second one and put better one an bottom. Trim excess part.
• Place biggest TPU seal between bottom and middle part 
• Screw them together 
• Place Your electronic components
  • Display - bend upper arms outside push display down;
  • ESP just slides down
  • MH - spread “gate” outside and place it down
  • SEN :
    • place other TPU sealings
    • place down SEN at angle that bottom part aligns with side brackets and top part sliced touching wall 
    • check if TPU sealings are on their place
    • move top of SEN under securing arm
• Attach upper part

Notes:

• Top part holds on magnets for better maintenance;
• Bottom one is screwed together with the middle for sealing measures. 

Specification of SEN requires isolating inlet and outlet channels and I was not able to make use of off-shelf sealings such as rubber orings so in my opinion TPU is necessary.

I will pass on placing my particular ESPhome configuration :

- It is fairly easy to start running;

- DYOR and adjust configuration to your use case;

Print with non volatile materials PLA and TPU
 

You can basically treat this as platform for your own air quality sensor with different sensors.

Things to improve:

- It is tricky to screw bolts beneath SEN clamp and magnets. 

- After thermal imaging I am sure that there is no significant heat creep but in Your use case you may consider adding a double wall inside the middle chamber.

Mind that Your sensor size may vary for example my SEN module was off ~1mm from what their 3D model was.

On my printer supports were needed on:

• top part magnet holders 
• middle part wall shift going inside bottom part
• middle part insert holders