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# System prepended metadata

title: Power and Hardware 2021-2022 Debrief

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# Power and Hardware 2021-2022 Debrief

## Observations/Problems

### Design Phase
- Change in design specs
    - **Did not have specific component list by CDR**
    - P&H descision making and planning is dependent on finalizations from other subteams 
    - List by CDR
       - Drivetrain
           - Encoders (4 total): velocity control 
       - Excavation
            - Current Feedback on exc motor: prevent motor stalling
       - Actuation
           - Limit Switches (6 total):
               - 2 for stopping left linear actuator (full extension and halfway)
               - 2 for stopping right linear actuator (full extension and halfway)
               - 2 for lead screw actuation (full extension and zero extension)
       - Deposition
          - Limit Switches (2 total): 2 for stopping deposition movement
       - Weight Sensor:
          - For determining when enough gravel has been mined
    - Additional changes
        - Reduced 8 limit switches to 3 hall sensors
        - LED signal 
- Didn't need 5V step down if we used motor controllers that provided a 5V output voltage, saving space
    - Sabertooth motor controllers have 5V output
- Custom motor controllers vs Sabertooths
    - Cost
    - Size
- Component Placement
    - Need component list to define the size of the box
    - Hard to incrementally do component placement
    - Constant components
        - Motor controllers
        - Encoders
        - Jetson + teensy
        - power distribution

### Manufacturing 
- Not clear which pin on the bulkhead is routed to which pin on the teensy
    - Routing done prior to assembly would simplify this greatly
- Not clear which spreadsheet has what information
    - A table of contents as minimum would be greatly helpful to find information
- Very easy to mess up the orientation of the bulkheads while soldering it (Happened twice)
- Had to ask to get the PCB layout multiple times, easiest and best piece of documentation for assembly
- Had the Teensy USB port get ripped off multiple times
    - Use USB pins with ttyl cable instead of micro usb?
        - doesn't work, better option is to route the cable more safely so when it bends it doesn't apply a lot of torque on the usb port
![](https://i.imgur.com/1X4jacm.png)
- Got the ebox too late (April-May instead of February)
- Lot of waiting


### Mitigations

- Clearer Documentation
    - Datasheet (Software/P&H)
        - Includes full schematic with pinouts
        - Full component list with links to respective datasheets (for easy ctrl-F)
        - Define clear notation of robot and actuators (i.e front-left drive motor, excavation motor, left linear actuator, right linear actuator, assume front is in direction of tool, forward is +x direction, etc)
        - Full component placement diagram with wiring done in Solidworks and wire lengths ([link](https://www.cati.com/blog/how-to-create-a-solidworks-electrical-route/))
        - Battery handling (could be added in wiki)
        - Due with robot CAD in January?
        - Space for changes in design
        - If changes are made, need to go through official approval
- Proactive Communication 
    - P&H should make a specific list of what the minimum information is needed to proceed with planning (type of sensors, box size etc.)
- Design
    - Put battery outside box
    - Plastic box with sealed enclosure like a lunchbox
        - Potentially outsource box design to Protocase
        - Search "plastic waterproof electrical enclosures" on google
        - Need specified dimensions first
        - Create a P&H box and design the mechanical system around that
    - Wire routing in design phase, either through Solidworks or by hand
        - ** need to have component list first