diff --git a/sources/2890/canjectors.md b/sources/2890/canjectors.md index a2796b8..09673c0 100644 --- a/sources/2890/canjectors.md +++ b/sources/2890/canjectors.md @@ -22,30 +22,10 @@ After experiencing **critical CAN bus failures** during competition, Chris desig The design philosophy: prevent wiring failures from killing the robot mid-match. -## Design Basis - -Chris studied the **SWYFT CANnect** system as inspiration: -- Run CAN bus + 12V power over standardized cabling -- Easy connector system (WAGO lever terminals) -- Built-in CAN termination options -- Robust form factor - -Canjectors go further with custom modifications for Team 2890's specific failure points. - -## Current Design: Middle Canjector - -The schematic shows the "middle" Canjector variant with: -- **12V power** passthrough -- **3 CAN connections** (RJ45 connectors) -- **WAGO terminal blocks** for clean wiring (2601-1104 series) -- **120Ω termination resistor** (R4) between CAN signal lines — switchable -- **Power indicator LED** (green, 0603) with 470Ω current limiting resistor -- **2-pin header** for additional configuration - ## Key Features -- **Dual CAN paths** — each Canjector bridges multiple CAN segments -- **Integrated termination** — 120Ω resistor switchable per segment +- **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 @@ -53,30 +33,24 @@ The schematic shows the "middle" Canjector variant with: ## Design Variants -Chris designed five Canjector variants. **Names are printed on the physical PCBs** — Endz, Major, Minor are the actual designations. +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 | Primary role | -|----------|-----------|----------|-------------| -| **Start** | 1 | 1 | Bus origin at PDH side | -| **Minor** | 3 | 1 | Single wheel module — CANcoder + 2 motors | -| **Middle** | 3 | 2 | Mid-chain node + power distribution | +| 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 | -| **Endz** | 1 | 1 | USB diagnostic tap — serves as first OR last device in chain | -**Minor — single wheel module design:** +### Minor — Single Wheel Module + +One Minor per swerve corner: - 1 CANcoder (CTR Electronics CAN FD magnetic encoder for steering feedback) -- 2 motors (typically drive motor + steering motor, or drive + mechanism) +- 2 motors (drive + steering per MK4i) - 1 12V output for accessories -Minor was designed for MK4i swerve modules — one Minor per wheel handles the CAN bus connections for the encoder and both motors. Clean single-point connection for each corner of the robot. - -**Note on overlap:** -- Start and Endz both serve end-of-chain positions (first or last device) -- Minor and Middle both have 3 CAN ports — Middle adds a second 12V output for power distribution - -All Canjectors use the same shunt-activation scheme for 120Ω termination. This means any variant can terminate the bus when needed. +Clean single-point connection per wheel — troubleshooting localizes to one module per corner. ## Connection to Training @@ -90,20 +64,16 @@ All Canjectors use the same shunt-activation scheme for 120Ω termination. This 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. -## Notes for MrC - -This is a **confidence builder** for the training vault — it shows Chris's practical engineering under pressure. Good story for students: identify the problem, study existing solutions, design your own, build it, test it. The full engineering cycle, not just code. - ## Files | File | Description | |------|-------------| -| `canjector-schematic.png` | Middle Canjector — EasyEDA schematic | -| `canjector-start-pcb.png` | Start variant — PCB layout (red solder mask) | +| `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, 6 CAN ports | -| `canjector-endz-render.png` | Endz variant — USB-to-CAN diagnostic interface | +| `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 | \ No newline at end of file +| `canjector-endz-gerbers/` | Endz variant manufacturing files |