0a6b9fcc26
Endz: 1 CAN, 1 12V, origin Minor: 3 CAN, 1 12V, single wheel (CANcoder + 2 motors) Major: 6 CAN, 2 12V, heavy distribution
80 lines
3.4 KiB
Markdown
80 lines
3.4 KiB
Markdown
---
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title: "Canjectors — Chris's Custom CAN Bus Interconnect System"
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tags:
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- hardware
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- electrical
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- can-bus
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- 2890
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- custom
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type: hardware-spec
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owner: 2890
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status: active
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sources:
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- "https://swyftrobotics.com/products/swyft-cannect-wiring-system"
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- "https://store.ctr-electronics.com/products/cancoder"
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---
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# Canjectors — Custom CAN Bus Interconnect System
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## Overview
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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.
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The design philosophy: prevent wiring failures from killing the robot mid-match.
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## Key Features
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- **Modular CAN distribution** — one board per functional zone
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- **Integrated termination** — 120Ω resistor switchable via shunt jumper at any position
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- **Power LED** — visual confirmation that 12V is present
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- **RJ45 connectors** — industry standard, easy to cable, robust
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- **WAGO 2601 series** — tool-free, reliable terminal connections
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- **Designed in EasyEDA** — schematic dated 2026-04-09
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## Design Variants
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Three Canjector variants. **Names are printed on the physical PCBs.**
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All variants support configurable termination via a shunt jumper — populate the shunt to activate 120Ω termination anywhere in the chain.
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| PCB Name | CAN ports | 12V outs | Role |
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|----------|-----------|----------|------|
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| **Endz** | 1 | 1 | Origin — first device in chain, PDH side |
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| **Minor** | 3 | 1 | Mid-chain — single wheel (CANcoder + 2 motors) |
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| **Major** | 6 | 2 | Heavy distribution — end of main runs |
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### Minor — Single Wheel Module
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One Minor per swerve corner:
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- 1 CANcoder (CTR Electronics CAN FD magnetic encoder for steering feedback)
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- 2 motors (drive + steering per MK4i)
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- 1 12V output for accessories
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Clean single-point connection per wheel — troubleshooting localizes to one module per corner.
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## Connection to Training
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**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:
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- **Redundancy** — when one path fails, traffic routes around it
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- **Termination** — 120Ω at each end of the bus, switchable at intermediate nodes
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- **Visual debugging** — power LEDs let you confirm connectivity at a glance
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- **Modular design** — if one Canjector fails, replace it in minutes
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## Why This Matters
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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.
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## Files
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| File | Description |
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|------|-------------|
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| `canjector-schematic.png` | Minor variant — EasyEDA schematic |
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| `canjector-start-pcb.png` | Endz variant — PCB layout |
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| `canjector-minor-render.png` | Minor variant — 3D render, blue PCB |
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| `canjector-major-render.png` | Major variant — 3D render, blue PCB |
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| `canjector-endz-render.png` | Endz variant — USB-to-CAN diagnostic |
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| `canjectors.md` | This documentation file |
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| `canjector-gerbers/` | Major variant manufacturing files |
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| `canjector-minor-gerbers/` | Minor variant manufacturing files |
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| `canjector-endz-gerbers/` | Endz variant manufacturing files |
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