Box Turtle AFC-IO Board / Input-Output Box Turtle (BT-IO)

Box Turtle AFC-IO Board (BTIO) — Centralized I/O Hub for BoxTurtle AMS Filament Changer, CAN + USB, Daisy-Chain Expansion, No-Solder Toolhead Buffer Adapter

The Box Turtle AFC-IO Board (BTIO) is the wiring backbone that transforms a BoxTurtle build from a tangle of individual cables into a clean, serviceable, and expandable system. It serves as a centralized I/O hub between your Klipper printer, the BoxTurtle AFC-Lite controller, and your toolhead buffer — consolidating all critical connections into one board that mounts flush into the BoxTurtle's right rear skirt position. Whether you're running a single BoxTurtle unit over USB or daisy-chaining multiple units on a CAN bus with external 24V power, the BTIO handles the transition cleanly, without adapters, splices, or soldering.

⚠️ BoxTurtle kit required. The BTIO is an add-on I/O board — it does not include the BoxTurtle kit, AFC-Lite board, or any filament changing hardware. It is a dedicated accessory for BoxTurtle builds already in progress or completed.
⚠️ Printed mounting parts required. The BTIO installs in place of the right_rear_skirt panel. You must print the [a]_option_plate and install two M3 heatset inserts before mounting. Download STLs from the ArmoredTurtle AFC-Accessories GitHub before ordering.
⚠️ 24V power required for CAN operation. The AFC-Lite PCB does not support USB Power Delivery. When connecting via USB-C for data, you must still supply 24V and GND to the CAN bus port pins for power. The BTIO enables external power delivery for USB operation — plan your power routing accordingly.

One Board, Every Connection — Clean Wiring from Day One

The BTIO addresses the most common pain point in BoxTurtle builds: wiring management. Without it, connecting the printer, toolhead buffer, and expansion units means routing separate cables to separate ports across the BoxTurtle frame. The BTIO consolidates all of this into a single board at the rear skirt — one connection to the printer, one to the toolhead buffer via the dedicated TN port, and a daisy-chain port for multi-unit expansion. Swapping between USB and CAN control, or between CAN bus power and an external 24V PSU, happens at the board without opening the enclosure or touching internal wiring.

USB + CAN in One Board — Switch Without Rewiring

The BTIO supports both USB-C and CAN bus communication with the host printer. This matters in practice because BoxTurtle builds often start on USB for initial commissioning and calibration, then move to CAN for permanent installation. With the BTIO, that transition is a cable swap at the board — not a rewire. Similarly, power can come from the CAN bus (from the printer's 24V supply) or from a dedicated external PSU depending on your setup, and the BTIO handles both without modification.

Common Ground Design — Electrical Stability Across All Ports

With the exception of USB lines, all ground connections on the BTIO share a common ground. This simplifies wiring because you don't need to manage separate ground references for different ports — signal integrity is maintained across the printer connection, toolhead buffer, and expansion chain simultaneously. USB ground is intentionally isolated to prevent ground loop issues that are common when mixing USB and powered CAN connections on the same board.

TN Port — No-Solder Toolhead Buffer Repin

The dedicated TN (TurtleNeck) port is engineered specifically for toolhead buffer integration — and includes a practical detail that saves time during installation. Although only one ground pin is electrically required for the toolhead buffer signal, the TN port provides two ground pins that mirror the original toolhead buffer connector layout. This means you can repin your existing toolhead buffer cable directly into a single BTIO-compatible connector without soldering — just move the pins over and plug in. No heat, no flux, no continuity risk from cold joints.

Daisy-Chain Expansion — Scale to 16 BoxTurtle Units

The BTIO supports daisy-chained configurations for multi-unit BoxTurtle expansion. The BoxTurtle system supports up to 16 connected units (up to 64 filament spools) — and the BTIO's daisy-chain port is what makes clean multi-unit wiring possible without running independent cable runs back to the printer for each unit. Plan your expansion from unit one and avoid reworking wiring later.

Skirt-Mounted — Integrated Into the BoxTurtle Frame

The BTIO replaces the right_rear_skirt panel on the BoxTurtle frame, mounting flush to the rear using two M3×6 SHCS into the printed option plate and two additional M3×6 SHCS threaded directly into the plastic. All external connectors face outward from the skirt, keeping the BoxTurtle's interior clean and all service points accessible from outside the unit.

Specifications

What's Included

What's NOT Included

Who Is This For?

The BTIO is the right add-on for any BoxTurtle builder who wants clean, maintainable wiring from the start — or who is retrofitting a completed BoxTurtle that currently has cables routed ad-hoc to the printer. It's particularly valuable if you're planning to expand to multiple BoxTurtle units, run CAN bus, or need to integrate a toolhead buffer without modifying existing cable assemblies. If you're building the BoxTurtle from scratch, order the BTIO alongside the main kit — installing it during the initial build is significantly easier than retrofitting it later.

Resources

• ArmoredTurtle GitHub — BTIO STL files, wiring diagrams, and installation guide
• ArmoredTurtle Documentation — BoxTurtle Wiring Guide (CAN, USB, power routing)

Explore the full BoxTurtle accessory ecosystem at 3D Printer Electronics, or browse all compatible upgrades at 3D Printer Upgrades.