Pyxida Priorities

  • Pyxida Fixes for components - no functionality change
  • VN100 as flight critical unit
    • Modify breakout port
    • Ruggedized VN100
  • Satisfy redundancy strategy - currently thinking similar redundancy w/Pyxida
  • Battery design strategy - all power systems go through avionics
  • Locking connectors, everywhere all the time (SMA recommended, should work)
  • Other high accuracy, high precision sensors

Other Boards To Develop

BMS Board

  • Read voltages off batteries on vehicle, send to pyxida
  • Top up batteries from off-vehicle power
  • Maintain independent redundancy - no associated failure modes

BBC Multiplexer

  • Can power cameras (contingent on the more robust camera)
  • Can tell if cameras are running

Camera Breakout to Camera

  • Kill the weird 10 pin USB

Time Budget Skills

Pyxida redesign is order of months and two revisions. Approximately $1600. We need serious support on the EE side since we've lost Shreeyam and Jacob. PCB layout skills will be critical to support multiple objectives.

VN100 is a very pricey unit, approximately $800/piece. Sponsorships possible.

Redundancy requires system level thinking and integration experience. Likely a job for team-lead.

Battery design strategy saves approximately 100 grams per stage. Generic electronics skills required. Requires buy-in from other teams, especially payload. FSAE has significant experience.

Locking connectors, design changes happen in parallel with Pyxida revision. Connectors are approximately $10/pair. Eliminates serious flight risk.

Investigating other sensor options helps with altitude determination and verification. This task is unbounded and uncosted. Literature review required to identify candidates.

BMS board needs interface with structures- tube pass through, mechanical engineering skills.

BMS board needs PCB layout. FSAE has significant experience. Cost ~$300.

BBC Multiplexer needs PCB layout. Cost ~$100

Camera Breakout board need PCB layout and very find soldering skills. Cost ~$100

 

Dennis Pyxida 7 improvement ideas

+ antenna switch (modification already done in pcb layout)

- enables experimental designs of patch antennas, one in the NC and one in the bay itself

- in case of one antenna gets lost (like happened for Hermes2)

 

+ fix Piezo footprint

- the pins are to close In Rev6 and required bending of the Piezo wires.

 

+ EMI/RFI shielding

- Reason: we have a harmonics on the same frequency as GPS. If we use a very bad antenna, we get RFI which degrades GPS

- Surface Mount EMI/RFI Shield Clips around all RF parts (unclear if separate for C1200 and C1190)

- requires relocation of programming pins and maybe the

- optional: Shieldings around IMU and Baro

 

+ Changing SPI flash from WSON8 to SOP8 packaging

- IC is thicker in SOP8

- is simpler to unsolder from PCB

- It showed, that the pins of the SOP8 on the Telemega acted somehow as buffers at impact.

 

+ Conformal coating

- coat all parts with conformal coating (except for baro)

- protection of the parts against environment (e.g. moilsture, heat of burning lipos, etc)

- keeps all parts hopefully together

 

+ metal shield on the backside of the pcb with rubber spacers

- protects the backside of the pcb

- acts as additional EMI shielding

 

+ adding additonal SD card slot similar to LE on the backside of the PCB

- we have a lot of space on the back of the PCB

- SD cards are easy to handle, as proven by LE

 

+ adding the BT 5.0 module on the back side of the PCB

- can be used for experiments of an internal rocket communication

- potential use in a black box system

 

 

 

 

  • No labels

1 Comment

  1. Unknown User (astrocrg@mit.edu)

    Dennis Giese BT 5.0 is unnecessary and adds complexity and cost to Pyxida. There is no flight critical justification for intra-rocket comms, especially with the booster architecture allowing wires to reach everything. SD cards are bad and sad under vibe, and I'd rather improve telemetry. I agree with the rest.