Intro
Who
Engineer: Meghan Dang
Manager: Daniel Puratich
Why
we want to space ESCs out, have a higher datarate, and less harness complexity
CAN supported ESCs exist but more expensive and not what we have alr, we like what we have right now
DSHOT is already a digital protcol that’s busable
single ended
prone to ground loops and common mode SI
100mil hdrs into pixhawk and from ESC
What
board solders onto the ESCs both DSHOT data pins that has a JST CAN connector to pixhawk
the firmware and hardware will not implement an ESC, we will continue to rely on COTS for this assuming the COTS solution features a standard DSHOT 100mil pitch connection (as the APD ESCs we have right now do)
firmware wise this is a CAN to bidirectional DSHOT adapter.
How:
small STM and a CAN transceiver, may require a little LDO for power, see below for design procedure
When
Starting Early June 2024
Table of Contents
Subpages
System Background/Research
most information pulled from 2024 System Architecture
Pixhawk
link to pixhawk docu for CAN transcievr
https://holybro.com/collections/autopilot-flight-controllers/products/pixhawk-6x
https://docs.holybro.com/autopilot/pixhawk-6x/technical-specification
https://ardupilot.org/plane/docs/common-holybro-pixhawk6X.html
APD ESC
note that other DSHOT supporting ESCs are similar pinout wise.
dshot has a sig in, a sig out, and a GND pin here
https://powerdrives.net/120f3 sales page
https://docs.powerdrives.net/products/f_series/quick-start-guide manual page
excerpt from their documentation:
Other Devices
ark CAN node
switched CAN termination is actually an insanely good idea for hobbiest CAN networks
Design
System Wiring Diagram
Diagram explains this board connects to ESC and rest of the system. Other CAN nodes should be implemented similarly. Daniel Puratich is handling this diagram to help set the stage and improve on diagrams from Custom CAN Hub and concepts discussed widely.
Schematic Wise
Most detail is on this board, but kind of describes the system.
Layout Sample
This is a starting place for a simple plane example, but shows how a layout could look with a full CAN architecture. Eventually battery bay could support more CAN and reduce harnessing there, but the battery bay and avionics will be very close to eachother so they’re lower priority than the farther away stuff.
CAN Header Selection
Will follow Pixhawk Electrical Connector Standards .
copy pixhawk for MPN
input and output CAN hdr
ESC Connection Selection
100mil hdr mount onto it
Micro Selection
some STM
https://discord.com/channels/776618956638388305/1241377889035882646/1242282003018154025
CAN Transceiver Selection
https://discord.com/channels/776618956638388305/1241377889035882646/1242282003018154025
copy pixhawk?
common mode choke plz
Power Decision
LM66100 for RPP
LDO to power the transciever?
how much capacitance
Schem High Level
Board Outline Sketch
Roughly how will system look?