Canjectors — Custom CAN Bus Interconnect System

Overview

After experiencing critical CAN bus failures during competition, Chris designed the Canjector system as a robust interconnect solution for Team 2890's robot. Modeled after the SWYFT CANnect concept but with custom design work, Canjectors provide reliable CAN + power distribution at all critical connections.

The design philosophy: prevent wiring failures from killing the robot mid-match.

Key Features

Modular CAN distribution — one board per functional zone
Integrated termination — 120Ω resistor switchable via shunt jumper at any position
Power LED — visual confirmation that 12V is present
RJ45 connectors — industry standard, easy to cable, robust
WAGO 2601 series — tool-free, reliable terminal connections
Designed in EasyEDA — schematic dated 2026-04-09

Design Variants

Three Canjector variants. Names are printed on the physical PCBs.

All variants support configurable termination via a shunt jumper — populate the shunt to activate 120Ω termination anywhere in the chain.

PCB Name	CAN ports	12V outs	Role
Endz	1	1	Origin — first device in chain, PDH side
Minor	3	1	Mid-chain — single wheel (CANcoder + 2 motors)
Major	6	2	Heavy distribution — end of main runs

Minor — Single Wheel Module

One Minor per swerve corner:

1 CANcoder (CTR Electronics CAN FD magnetic encoder for steering feedback)
2 motors (drive + steering per MK4i)
1 12V output for accessories

Hot-swap design: Unclip 2 ethernet cables + 4 power wires to motors = 6 wires total. Wheel module drops out, new one clips in. Designed for pit repairs — fast swap without soldering or rewiring.

Clean single-point connection per wheel — troubleshooting localizes to one module per corner.

Connection to Training

For students: CAN bus failures are among the most frustrating problems in FRC — a loose wire or failed connector kills the whole bus. The Canjector system teaches:

Redundancy — when one path fails, traffic routes around it
Termination — 120Ω at each end of the bus, switchable at intermediate nodes
Visual debugging — power LEDs let you confirm connectivity at a glance
Modular design — if one Canjector fails, replace it in minutes

Why This Matters

Chris experienced critical CAN failures at competition. The Canjector system is a direct response — solving the failure mode with custom hardware instead of hoping the stock connectors hold. This is the kind of real-world engineering that separates good teams from great ones.

Files

File	Description
`canjector-schematic.png`	Minor variant — EasyEDA schematic
`canjector-start-pcb.png`	Endz variant — PCB layout
`canjector-minor-render.png`	Minor variant — 3D render, blue PCB
`canjector-major-render.png`	Major variant — 3D render, blue PCB
`canjector-endz-render.png`	Endz variant — USB-to-CAN diagnostic
`canjectors.md`	This documentation file
`canjector-gerbers/`	Major variant manufacturing files
`canjector-minor-gerbers/`	Minor variant manufacturing files
`canjector-endz-gerbers/`	Endz variant manufacturing files

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