How to build TOPS
12-DoF four-legged robot dog · Advanced
TOPS ('SPOT' backwards) is Aaed Musa's 12-DoF quadruped with 90 kV motors, ODrive S1s, printed 9:1 planetaries and a Teensy 4.1. BOM is about $3,329; no license.
Many actuators, custom wiring and real tuning work.
Our estimate, part-time
$3,329.27 total from the TOPS BOM workbook
No license file
What is TOPS?
TOPS, short for Traverser of Planar Surfaces and 'SPOT' spelled backwards, is Aaed Musa's 3D-printed quadruped. Each joint pairs a 90 kV brushless motor with an ODrive S1, and a Teensy 4.1 coordinates them.
The hip and abduction joints use printed 9:1 planetary gearboxes, while the knees use a 9:1 belt reduction.
The build log is frank about limits: the knee belts skip, it can't jump, and each leg needs manual calibration at startup. The repo has no license file, so no reuse rights are granted.
TOPS specifications
- DoF
- 12
- Drivers
- 12× ODrive S1
- Reduction
- 9:1 planetary (hip/abad), 9:1 belt (knee)
- MCU
- Teensy 4.1
- Battery
- 6S 5200 mAh
Figures as published by the project. See Sources below.
Bill of materials
| Part | Qty | Notes |
|---|---|---|
| Leg assembly | 4 | $757.45 each in the source BOM |
| Teensy 4.1 | 1 | |
| 6S 5200 mAh 60C LiPo | 1 | |
| 16×2 LCD, switch, 5 V regulator, voltage display | — |
Where's the full bill of materials?
The full BOM, with exact quantities and vendors, lives in the project's own files. Prices change often, so treat $3,329 as a ballpark from the project. Start at the project repository.
Tools you'll need
- FDM printer
- Soldering iron
- ODrive GUI
- Arduino IDE
Step-by-step build overview
Electronics & wiring overview
The Teensy 4.1 commands twelve ODrive S1s. The 6S pack feeds the motor bus, and a 5 V regulator powers the logic.
Software
The project ships its own firmware and control code. See the repository for setup.
Teensy control code in the repo. It has no license.
Tips from the bench
- ☕ Upgrade the knee belts or tensioners, since skipping is a known issue.
TOPS FAQ
Is TOPS open source?
Its sources are public but there's no license, so reuse needs permission.
Sources
Written by Bots n' Beans from the project's own documentation. Check the sources for the latest revision before you buy parts.
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