Faze4 Robotic Arm

Faze4 — 6-Axis Cycloidal Robot Arm

Faze4 is a full-size 6-DOF desktop industrial-style robot arm, designed by Petar Crnjak and released by Source Robotics. It uses cycloidal reducers on all major joints (instead of the usual harmonic drives or belts), which gives it high payload capacity, near-zero backlash, and a noticeably beefier feel than a typical hobby arm.

What it is

• 6 rotational joints (classic industrial arm kinematics)
• Cycloidal reducers on joints 1–4
• NEMA 23 and NEMA 17 steppers with closed-loop encoder feedback
• Custom distribution PCB that fans out from a single controller to all joint drivers
• ~1000 parts total, roughly 15 kg assembled
• Work envelope ~650 mm reach

What it does

Faze4 lives in the "aspirational build" slot on this catalog. It's not a weekend project — it's a multi-week build with real machining decisions, bearings to press, and PCBs to populate. What you get at the end is a genuinely industrial-feeling arm that can move real weight and repeat positions accurately enough to pick and place non-trivial payloads.

Typical uses the community has shown:

• Pick-and-place with suction or a custom end-effector
• Light pen plotting and laser marking
• Educational kinematics demos (forward/inverse, Jacobians, singularities all matter here in a way they don't on a 5g gripper toy)
• ROS/MoveIt integration experiments

Cost and effort

Roughly $1000 in parts (steppers, bearings, PCBs, fasteners, some aluminum) plus ~3 kg of filament for the printed structure. Expect 40–80 hours of build time end-to-end.

Printed parts

Seven canonical mesh groups make up the structural skeleton:

• base_link — stationary base housing
• rotary_base — joint 1 rotating platform
• nadlaktica — upper arm (joint 2 link)
• lakat — elbow (joint 3)
• podlaktica — forearm (joint 4)
• saka — wrist (joints 5/6)
• hvataljka — gripper body

Each of these is itself a multi-part assembly in the full BOM (halves, endcaps, motor mounts) — the STLs attached here are the canonical collision/visualization meshes straight from the URDF. See the upstream repo for the full printable set.

Software

Firmware ships in the upstream Faze4_test_code_1.0 tree (teensy/Arduino-style C++). The community has working ports to ROS via a separate package. The control surface exposed by this orobot program assumes a Raspberry Pi front-end talking to the arm's low-level controller over serial — see Documentation for the bridge contract.

Attribution & license

• Designer: Petar Crnjak / Source Robotics
• Upstream: https://github.com/PCrnjak/PAROL6-Desktop-robot-arm (sibling project — see Faze4 repo for this specific arm)
• Hardware license: CERN OHL S (Strongly Reciprocal)
• Build docs: https://source-robotics.readthedocs.io/
• Community: Source Robotics Discord + Hackaday build log

Links

• Upstream repo: https://github.com/PCrnjak/Faze4-Robotic-arm
• Read the Docs: https://source-robotics.readthedocs.io/
• Hackaday writeup: https://hackaday.com/tag/faze4/