Sensor Head Mount PDR
Project Scope
The sensor head mount is used to collect soil data as part of the science mechanism to analyze it and determine whether the soil should be studied further by being collected. Incorrect readings on temperature, carbon dioxide, or moisture sensors can threaten the success of the science mission. The sensor head mount allows the sensors to interface with the soil with the right conditions.
Success Factors
Relevant Competition Rules
Teams are given between 20 and 35 minutes to collect data with the rover
At each site the team needs to determine the absense or presense of life
Criteria | Constraints |
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Sensor head should aim to minimize weight | Sensor head must be attached by the holes on P0233 and as such there is a limit to how large it can be before it deforms |
Allow the moisture sensor to collect data from the soil | Sensor head must not interfere with P0233 or any other components like the dinolite camera |
Allow the C02 sensor to collect data from soil | Allow the dinolite microscope camera to be rotated and refocused |
Allow the temperature and humidity sensor to collect data from the soil | CO2, moisture, and temperature and humidity sensors need to be positioned lower than the bottom of the orange and cyan 3d printed parts (the black line showing the edge of the soil) (See picture) If the sensors are positioned above that point then when being lowered into the soil, the blue and cyan parts will interfere with it. 
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Design Concepts
Pictures, sketches, low level CAD of design concepts
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Cons: Sensor is harder to insert into the soil Pros: Smaller shroud allowing for better sealing of the environment
| Cons: Shroud width is larger relative to its depth which results in worse sealing Pros: The sensor can more easily be inserted into the soil |
Design Concept 1 |
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Design Concept 2
| Note: the DHT22 sensor (pink) will have a similar enclosure as in Design Concept 1 |
How would these systems work? DHT 22 and CO2 sensors both have a shroud which covers the sensors as they are lowered into the soil. The soil moisture sensor is simply lowered into the ground.
What are the risks associated with each individual design concept? Design concept 1 takes up more space and weighs more and is more complicated. It also has more complex geometry meaning that it will be harder to 3D print.
Design concept 2 has a center of mass that is farther from the mount platform meaning that it is more likely to deform. Depending on the length of the mounting bolts the platform is more likely to be damaged upon pluging into the soil.Design Proposal
What design concept do you want to move forward with? I want to move forward with Design Concept 2
Justify this decision by completing the following:
How could this design compare to established criteria and constraints? The design is not so large that it would make rotating the dinolite camera a problem. It would allow the sensors to successfully collect their data. It meets all the constraints.
Is there risk associated with achieving any requirements? The moisture sensor is positioned a little lower than the other sensors which is not ideal. The final design would aim to have them all located at similar heights.How are identified design risks planned to be mitigated? To prevent the platform from deforming after plunging into the soil, several long bolts will connect it to P0233. It will also use a number of ribs to prevent it from bending and snapping.
Very quick thoughts on what resources you may need to build and fabricate your design. The design will be 3D printed. It will require a few bolts to affix it to P0233, and to affix the sensors to the platform.
What is your proposed project timeline?
Propose a CDR date - Nov 27th