# Thor 6-DOF Robotic Arm A professional-grade, open-source 6-axis robotic arm designed by Ángel Luis Martínez. Thor is fully 3D printable, affordable (€250-350), and suitable for educational projects, research, and maker applications. ## Quick Specs - **Type**: 6-DOF (Degrees of Freedom) robotic arm - **Height**: 625mm (fully extended) - **Payload**: 750g (including end effector) - **Motors**: 6x NEMA 17 stepper motors (23Nm holding torque) - **Configuration**: Yaw-Roll-Roll-Yaw-Roll-Yaw joint arrangement - **Cost**: €250-350 (electronics ~€205, mechanical ~€137) - **Build Time**: 2-4 weeks - **Skill Level**: Intermediate (3D printing + electronics assembly) - **License**: CC-BY-SA-4.0 (open source, attribution required) ## What's Included - **49 STL files** - all parts ready to 3D print (PETG/PLA) - **40+ CAD files** - FreeCAD sources for customization - **Assembly guides** - step-by-step 3D assembly instructions - **Control code** - JavaScript interface with home/demo/custom motion functions - **Configuration** - 6-axis motor mapping with angle ranges and speeds - **BOM** - detailed parts list with sourcing information ## Getting Started 1. **Review this GitHub repo**: https://github.com/AngelLM/Thor 2. **Read the official docs**: https://thor.angel-lm.com/documentation/ 3. **Print the parts**: Download 49 STL files, slice for 3D printer 4. **Source electronics**: Arduino Mega 2560 + 6x NEMA 17 steppers + drivers 5. **Build the arm**: Follow 3D assembly instructions 6. **Install firmware**: Choose GRBL, RRF, or custom Arduino firmware 7. **Use this program**: Control Thor with home position, demo motion, and custom sequences ## Hardware Requirements - Arduino Mega 2560 (or compatible microcontroller) - 6× NEMA 17 stepper motors (23Nm) - 6× stepper drivers (A4988 or DRV8825) - 24V/5A power supply - 6× endstop switches (homing) - 3D printer (for 49 parts: ~50-100+ hours print time) - M3/M4/M5 fasteners and threaded inserts - GT2 pulleys, timing belts, 3D-printed gears ## Firmware Options Thor is firmware-agnostic. Choose one: - **GRBL** - CNC standard, simple G-code control (recommended for beginners) - **Repetier Firmware (RRF)** - Full 3D printer stack, mature & proven - **Custom Arduino** - Direct motor control (educational, more complex) - **Thor-ROS** - ROS2 integration for advanced kinematics & Moveit2 planning ## Community & Resources - **Official website**: http://thor.angel-lm.com/ - **GitHub**: https://github.com/AngelLM/Thor (all files, CAD, docs) - **Discord**: https://discord.com/invite/a5dSVqSUK5 - **Forums**: http://thor.angel-lm.com/forums/ - **BOM & sourcing**: https://thor.angel-lm.com/documentation/bom/ - **Assembly**: Interactive 3D assembly instructions at official docs ## Control Software This program provides basic motion control: - **Home Position** - return all motors to safe zero position - **Demo Motion** - pre-programmed coordinated arm movement (45° range) - **Custom Motion** - define custom angle sequences for your tasks - **Emergency Stop** - immediate motor shutdown For advanced control, see **Asgard** (https://github.com/AngelLM/Asgard) - the official Thor UI. ## Important Notes - **Firmware Integration**: Thor requires you to provide your own microcontroller & firmware. This program provides control templates; firmware installation is on you. - **Print Settings**: Use PETG (recommended) or PLA with 15-20% infill, 0.2mm layers - **Assembly Sequence**: Start with base → joint 1-6 → gripper. Print parts in this order. - **Safety**: Always disable power before manual adjustments. Stepper motors are strong — keep hands clear during operation. - **Customization**: All designs are open source (CC-BY-SA). Community has created variations, larger variants (XL), and specialized end effectors. ## Creator **Ángel Luis Martínez (AngelLM)** - GitHub: https://github.com/AngelLM - Active maintainer with strong community support - Used in robotics education & research worldwide ## Next Steps 1. Visit https://github.com/AngelLM/Thor to download all files 2. Read the complete BOM at https://thor.angel-lm.com/documentation/bom/ 3. Join the Discord community for build questions 4. Use this program to control your built robot
| Item | Qty | Unit Cost (USD) | Total (USD) | Notes | |------|-----|-----------------|-------------|-------| | NEMA 17 Stepper Motor — 40mm body, 39.22 N·cm holding torque | 1 | $14 | $14 | Joint 1 (base) — [Amazon search](https://www.amazon.com/s?k=NEMA+17+stepper+motor+40mm) / StepperOnline | | NEMA 17 Stepper Motor — 34mm body, 121.2 N·cm high-torque | 3 | $20 | $60 | Joints 2–3 with 5:1 reduction — [Amazon search](https://www.amazon.com/s?k=NEMA+17+stepper+motor+high+torque+34mm) | | NEMA 17 Stepper Motor — 34mm body, 21.57 N·cm | 3 | $13 | $39 | Joints 4–6 — [Amazon search](https://www.amazon.com/s?k=NEMA+17+stepper+motor+34mm) | | Arduino Mega 2560 R3 | 1 | $25 | $25 | Main controller — [Amazon search](https://www.amazon.com/s?k=Arduino+Mega+2560) | | A4988 Stepper Driver (with heatsink) | 8 | $2 | $16 | One per stepper + spare — [Amazon search](https://www.amazon.com/s?k=A4988+stepper+driver+module) | | 12V 10A Power Supply (DC barrel) | 1 | $20 | $20 | Drives all motors — [Amazon search](https://www.amazon.com/s?k=12V+10A+power+supply) | | Optical Endstop Module (3.3–5V) | 4 | $3 | $12 | Joint homing — [Amazon search](https://www.amazon.com/s?k=optical+endstop+module+3D+printer) | | Mechanical Micro Endstop | 1 | $2 | $2 | Limit switch — [Amazon search](https://www.amazon.com/s?k=micro+endstop+3D+printer) | | 40×40×10mm 12V Cooling Fan | 7 | $4 | $28 | Driver/motor cooling — [Amazon search](https://www.amazon.com/s?k=40mm+12V+cooling+fan) | | GT2 Closed Belt — 208mm (104 teeth), 6mm wide | 2 | $5 | $10 | [Amazon search](https://www.amazon.com/s?k=GT2+closed+belt+208mm) | | GT2 Open Belt — 1m, 6mm wide | 1 | $7 | $7 | [Amazon search](https://www.amazon.com/s?k=GT2+open+belt+6mm) | | GT2 Pulley — 20 teeth, 5mm bore | 3 | $3 | $9 | [Amazon search](https://www.amazon.com/s?k=GT2+pulley+20+teeth+5mm) | | GT2 Pulley — 40 teeth, 5mm bore | 2 | $5 | $10 | [Amazon search](https://www.amazon.com/s?k=GT2+pulley+40+teeth+5mm) | | Bearing 16014ZZ (70×110×13) | 1 | $10 | $10 | Base slewing bearing — [Amazon search](https://www.amazon.com/s?k=16014ZZ+bearing) | | Bearing 625ZZ (5×16×5) | 11 | $1 | $11 | [Amazon search](https://www.amazon.com/s?k=625ZZ+bearing+10pcs) | | Bearing MF84ZZ (4×8×3 flanged) | 2 | $1 | $2 | [Amazon search](https://www.amazon.com/s?k=MF84ZZ+flanged+bearing) | | 6mm steel balls (loose, ~30 ct) | 1 | $5 | $5 | Slewing ring — [Amazon search](https://www.amazon.com/s?k=6mm+steel+balls+bearing) | | Steel rod 4mm × 14mm | 2 | $1 | $2 | Cut from longer rod — [Amazon search](https://www.amazon.com/s?k=4mm+steel+rod+stock) | | Steel rod 5mm — assorted lengths (14.5, 32, 102, 128 mm) | 4 | $2 | $8 | Cut from one 5mm rod — [Amazon search](https://www.amazon.com/s?k=5mm+steel+rod+stock) | | M3 fastener kit (bolts 6–46mm + 90 nuts) | 1 | $20 | $20 | Project-specific assortment — [Amazon search](https://www.amazon.com/s?k=M3+screw+nut+assortment+kit) | | M2 nuts (qty 2) | 1 | $5 | $5 | Smallest pack — [Amazon search](https://www.amazon.com/s?k=M2+nut+pack) | | M5×18 bolt + M5 self-locking nut | 1 | $3 | $3 | [Amazon search](https://www.amazon.com/s?k=M5+18mm+bolt+nyloc) | | Dupont jumper wires + 2.54mm header pins/sockets kit | 1 | $10 | $10 | Wiring harness — [Amazon search](https://www.amazon.com/s?k=dupont+jumper+wire+header+pin+kit) | | 22 AWG silicone hookup wire (assorted colors) | 1 | $15 | $15 | Motor power wiring — [Amazon search](https://www.amazon.com/s?k=22+AWG+silicone+wire+kit) | | 2-pin PCB Terminal Block (5.08mm, THT) | 2 | $1 | $2 | [Amazon search](https://www.amazon.com/s?k=2+pin+PCB+terminal+block+5.08mm) | | 1N4004 Diode + MF-R700 Polyfuse + SMD passives kit (R/C/LED 1206) | 1 | $10 | $10 | Driver shield SMD parts — [Amazon search](https://www.amazon.com/s?k=SMD+1206+resistor+capacitor+kit) | | ThorControlPCB (Arduino Mega shield, manufactured) | 1 | $30 | $30 | Optional vs hand-wiring — [GitHub](https://github.com/AngelLM/ThorControlPCB) | | 3D-printer filament (PLA, 4 kg total) | 4 | $20 | $80 | Assembled from STLs in repo — [Amazon search](https://www.amazon.com/s?k=PLA+filament+1kg) | | USB-A to USB-B cable (Arduino programming) | 1 | $5 | $5 | [Amazon search](https://www.amazon.com/s?k=USB+A+to+B+cable) | **Estimated total: $380–$450 USD** (matches the project's stated "below €350" target). Source: https://github.com/AngelLM/Thor/wiki/Component-list and http://thor.angel-lm.com/documentation/.