Page Comparison

Inspiration

• LTE Breakout

• RPI Interface Rev B

Who

• Daniel Puratich hardware design

• Anthony Luo device selection, firmware

Features we aren’t adding but considered

• no ELRS

  • ELRS changes a lot quickly

  • could be saved for a future revision

• no cameras

  • mounting a camera makes placement complicated

Features

• Begin from RPI Interface Rev B

  • Keep the UART killswitch and one UART passthrough for the RPi to FC direct

  • Keep UART LED indicators

  • Keep CAN circuit

    • this can be used to control the lighting system

• Add an LTE modem to RPi interface rev c

  • relevant discord chat & here

  • quectel module he put

  • Quectel gets USB into the RPi

  • Selected to get maximum mavlink datarate out of the Pixhawk

  • This is not intended to be able to stream data for “groundside compute” for autonomy proccessing as explained in https://uwarg-docs.atlassian.net/wiki/spaces/ARCHS22/pages/2669412363/Autonomy+Compute+Integration+2025?search_id=fe948f35-631d-416c-b4d9-095d8cab5e37.

• Change buck converter to support 48V input so we can connect VBATT

  • this makes architecture decisions and harnessing easier

• Switch STM32

  • STM take in the three uarts form quectel

  • The other STM is smaller and doesnt have enough UARTs for this

  • STM will communicate with the RPi over SPI

• Increase board size a bit

  • this turns the board into a full normal RPi hat

  • This is required for cooling for the LTE module and a simple USB connection for the LTE hat

Part Numbers

• EG915NEAAC-N05-SNNSA

• STM32F415RGT6

Why

• Unlimited range & unlimited datarate is really attractive even if it comes at the cost of some weight and some power consumption.

• Maintainning Maintaining C2 link is required for flight so full reliance on ELRS is scary even if we have overwhelming evidence for it’s reliability

Block Diagram