Methane and Carbon Dioxide Case
Case specifically for use with the Figaro NGM2611-E13, Adafruit DHT22, AtlasScientific EZO-CO2 sensor, and an external power source. Which informs the sensor plate, cable glands, and power supply (length of case). [TODO: If we removed / generalized the sensor plate and cable glands requirements / instructions this could generally be for a 12” elongated case]: #
Bill of Materials and Potential Supplier or Drawing
| Item | Case Qty | Buy Qty | Supplier Part # / CAD link |
|---|---|---|---|
| 3” ABS Schedule 40 Pipe | 11” | 10’ | Menards 6881155 |
| 3” ABS Hub x Hub Coupler | 2 | 1 | Menards 6881537 |
| -341 EPDM 70A O-ring | 2 | 15 | McMaster-Carr 9557K316 |
| 18-8 Stainless Steel Threaded Rod 3/8” -16 | 3 | 2’ | McMaster-Carr 98920A031 |
| 18-8 Stainless Steel Hex Nuts 3/8” -16 | 24 | 100 | McMaster-Carr 91845A031 |
| 18-8 Stainless Steel Washers 3/8” | 24 | 100 | McMaster-Carr 92141A031 |
| 5” Copper Mesh/Gauze | 20” | 100’ | McMaster-Carr 6361T16 |
| Dow Corning 111 Molykote | Consumable | 5.3 Fl oz | McMaster-Carr 1204K32 |
| Dessicant Packet | 1 | 1000 | McMaster-Carr 2189K34 |
| 11” Cable Ties | 4 | 100 | McMaster-Carr 7130K55 |
| Dome Cap Cable Gland 1/2” NPT .19-.35” w/ O-Ring & Locknut | 1 | 1 | elecDirect RDC13NR |
| Dome Cap Cable Gland .11-.26” w/ O-Ring & Locknut | 1 | 1 | elecDirect RDC07AA |
| 3/4” wide Velcro | 1” | 5’ | McMaster-Carr 9273K13-9273K133 |
| 18-8 Stainless Steel Phillips Flat Head #6 x 1/2” Screws | 6 | 100 | McMaster-Carr 90065A148 |
| 3/4” x 3/4” Nylon Bar | 1’ | 1’ | McMaster-Carr 8732K17 |
| 1/4” Clear Acrylic Lid Plate* | 1 | NA | CAD Drawing 3inch |
| 1/4” Clear Acrylic Sensor Plate* | 1 | NA | CAD Drawing 3inch |
| 1/4” Clear Acrylic Cage Plate* | 1 | NA | CAD Drawing 3inch |
| ABS Cement | Consumable | NA | Menards 6932185 |
Diagrams
[TODO: add images to markdown file 
]:#
Annotated Case Diagram 3” Acrylic Plates CAD drawing
Build Process
Tools & Skills
- Horizontal/Vertical Metal Cutting Band Saw to cut steel threaded rod to length
- Reed TC4QP Tubing Cutter for plastic pipe to cut ABS to length
- 2x 9/16 SAE combination wrench for hex nuts
- Milwaukee 6in Diagonal Cutting Pliers for copper mesh and cable ties
- Measuring tape
- #2 phillips head screw driver / drill bit
Parts Fabrication
- Cut steel threaded rod in half to 1’ lengths
- Cut two 1-21/32” length sections of ABS, 20/32 to 22/32 is acceptable, too little won’t hold the o-ring in place, too much won’t compress the o-ring enough to seal properly
- Cut 20” of copper mesh x2
- Attach both cable glands through their respective holes in acrylic sensor plate
Assembly & Waterproofing
- Add cable glands to sensor plate
- Insert ABS 1-21/32” length into each end of coupling
- Add O-Rings around ABS
- Add nuts & washers to rods
- Add plates & housing to rods
- Wrap copper mesh around sensor cage and use cable ties to hold in place