Subsystem Build & Test
Table of Contents
Team Vision for Subsystem Level Build & Test Phase
|Phase 2 Team Vision||Phase 2 Accomplishments||Phase 3 Team Vision|
Test Results Summary
A preliminary version of the air quality test was completed this phase. It was run using both a humidifier and a water bottle filled with hot water, surrounded by low density polyethylene plastic. The procedure and results of both these tests are outlined in their own individual report linked below.
Additionally, a test tracker sheet was created to keep better track of when tests have been completed with a brief overview of their results.
Team sat down together to discuss various possibilities for mounting components that would result in the system taking away the least amount of space from the user and allowing the stroller to maintain its full range of collapsibility.
The battery will be mounted to the stroller within a 3D printed enclosure.
The team brainstormed a few solutions for mounting the battery to avoid offsetting weight and maintaining collapsibility of the stroller.
The battery box would be secured on parallel mounting bars welded or fasted on to the stroller frame. Slots would be cut into the parallels that screws would go through the top of the battery box to secure the box beneath the structure.
The main problem with this design option is that front wheel interferes with the space between the bars when collapsed. Additionally the orientation of the bars with the stroller offsets when collapsed, so any mounting bars for the battery would have to allow for automatic adjustability.
The battery box would be secured the bars that run beneath the basket. Fasteners would protrude through the basket material. Mounting screws would go through the bottom of the battery box to secure the box to the structure.
The main problems with this design option is that the battery box is taking away customer storage space and any electrical connections would need to be lengthened. This would increase the overall product cost and increase the risk of wires getting caught or cut.
The battery box would be secured the bars that run beneath the basket. Mounting screws would go through the top of the battery box to secure the box beneath the structure.
The main problem with this design is that the battery box is closest to the ground. The battery box would have the greatest exposure to harsh street environmental factors that could damage the structure and components: snow, salt, rain, dirt, rocks, etc.
The battery box would be suspended within a fabric sling that had a buckle and adjustable straps to tension the battery box in place behind the child's back.
The main problem with this design is the uncertainty in the product life-cycle of the fabrics that make up the sling. This method leaves more room for user misuse to occur. Additionally, if not secured properly, damage to the battery and system could be severe.
Temperature sensor was placed to be within carriage space to measure enclosure temperature. Casing options need to be determined to protect sensor from child and potential spills.
Microcontroller solutions were determined by the need of the display to be close to the caretaker to receive feedback from the system. Using the space formerly dedicate to the speakers and personal storage, the team will need to determine alternative personal device storage options or result in the customer losing this space to the technology.
Electrical SubsystemsThe following is an overview of what what accomplished this phase; For a more detailed document check the P18347 Electrical Subsystem Status Update document.
Arduino code and screenshots can be found in the following compressed folder. P18347 Subsystem Review Mirco-controller Demos & Code
Temperature Sensing SystemInitial decision to use the AD22100KT sensor that Ian already had has been reversed due to initial oversight in sensor's requirements for accurate data. Analog devices TMP36 sensor intended to be used instead.
Seat Heating SystemPreliminary testing done with NiChrome wire and polyurethane foam. 24AWG wire was used spaced 3 inches apart connected to the battery for the seat heater which was measured to be 12.644V. Complete data from test found here.
- Additional experimentation is needed to optimize the heater.
User InterfaceThe LCD shield kit purchased over break was inspected for damage and assembled. Once assembled Functionality was verified using the code provided by the manufacturer. Initial decision to use the push buttons built into the shield has been revised; instead, large push buttons similar to those found on a late 80's arcade game will be implemented.
Bill of MaterialsThe below document shows the current status of the Bill of Materials. The status of the items are color coded. Green represents items that the team has acquired, yellow stands for items that the team has ordered, but has not yet received, orange stands for the item is known and sourced, but the team is waiting to order, and the red stands for the item not being sourced or decided on yet.
We have continued to update our BOM and a Purchase order checklist (POC) accordingly. A separate finance sheet is maintained and updated, keeping track of all expenses along with each purchase made along with date and price of item. 90% of the items in the BOM have been ordered and rest 10% pending on certain decisions at this point of time.
Risk and Problem Tracking
- The updated Risk Management document can be viewed here.
- The following risks have been identified as problems: P18437 Problem Tracking Document.
Plans for next phase
- As a team, we plan on working to integrate our subsystems and continuing with our test plans
The teams three week plans for phase three of the project can be found at the following: P18347 MSDII Phase III Three Week Plans