The four Hackaday logs describe the design and testing, but there are no step-by-step instructions, so a builder works from the STEP model and the parts list. No license is stated for any of the files.
TOPS is a 12-joint, 13.4 kg quadruped built by Aaed Musa in 2023, with mostly 3D printed legs on a carbon fiber tube frame. Each joint uses a custom quasi-direct-drive actuator, which pairs a 90 KV brushless motor with a printed 9:1 planetary gearbox and an ODrive S1 controller, and a Teensy 4.1 sends commands over CAN. It took inspiration from James Bruton's openDog V3 and reached a square-step trotting gait.
At a glance
| Parts cost | $3,300 (2023) project · Stated by the designer as the total cost of his 2023 build, about $247 of it per actuator source ↗ |
|---|---|
| Difficulty | 5/5 Expert · Twelve custom brushless actuators with ODrive tuning, a 6S power system and custom gait code, assembled from a STEP model with no written steps. |
| Build time | About 4 months overall, including about 3 weeks of 3D printing source ↗ |
| Tools needed | 3D printer (about 3 weeks of printing, about 4.5 kg of printed parts), soldering and wiring for a 6S LiPo, CAN bus and ODrive power, cutting carbon fiber tubes (unconfirmed) |
| Motors | 12 custom QDD actuators, each a 90 KV brushless motor with a 3D printed 9:1 planetary gearbox and an ODrive S1 FOC controller, with belt-driven knees |
| Controller | Teensy 4.1 talking to the ODrives over CAN, with an RC receiver and a 16x2 LCD menu |
| Sensors | Motor encoders in the actuators only, no IMU listed |
| Published | ✓ Parts list✓ CAD/STL✗ Assembly guide✓ Wiring✓ Software✗ Video Four Hackaday.io narrative project logs plus a GitHub repo with a STEP assembly, a parts list spreadsheet, a schematic image, Arduino code and an inverse kinematics PDF. One YouTube overview video is linked but is not a build series |
| Activity | Last update 2023-10-06 · 299 GitHub stars · 45 forks on GitHub, 129 followers and 114 likes on Hackaday.io |
| Kits | None known |
Licenses
No license is stated for the design files. They are published for building, but without a license the right to copy, modify or redistribute them is not granted.
| Design files | None found (Hackaday page, repo and aaedmusa.com state no license for the CAD or parts list) source ↗ |
|---|---|
| Code | None found (no LICENSE file, and the GitHub API reports no license) source ↗ |
| Documentation | None found source ↗ |
Builder notes
Practical points from the project's issue tracker, forum and docs, each linked to its source.
- The designer said balancing will not be added to TOPS and is planned for a future quadruped instead. source ↗
- In the final build log the knee joints slip, so the robot has to be recalibrated after a skip, and the legs need manual calibration at every power-up. source ↗
- Knee belt tension was a problem during the single-leg jump tests, where the V2 leg jumped just under 3.5 inches. source ↗
- A builder in 2025 reported that the parts list spreadsheet opened empty. The designer said the file was fine and suggested downloading it again. source ↗
Other quadrupeds plans
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- Stanford Pupper v2.1 (DJI motor version) · $1,600 (2023) · difficulty 4/5
- openDog V3 · $2,800–$3,400 (2023) · difficulty 4/5
- MEVIUS (metal quadruped) · $12,400 · difficulty 4/5
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