How to build Q8bot
8-DoF four-legged robot dog · Beginner
Build Q8bot from UCLA RoMeLa: 8 DYNAMIXEL XL330 servos on a PCB chassis, an XIAO ESP32C3 over ESP-NOW, and a $337 BOM. It walks, trots, bounds and jumps.
Mostly printed parts and plug-in servos. Good first build.
Our estimate, part-time
$337.29 total from the project's sourcing sheet
MIT
What is Q8bot?
Q8bot comes from UCLA's RoMeLa lab. It's roughly the size of a phone but can walk, trot, bound and jump.
Its eight DYNAMIXEL XL330-M077-T servos plug straight into one custom PCB that is also the chassis, so there's no wiring harness. A Seeed XIAO ESP32C3 handles wireless control over ESP-NOW.
The repo includes CAD, Gerbers, PlatformIO firmware, Python tools and separate guides for sourcing, assembly and software. It was presented at IROS 2025.
Q8bot specifications
- DoF
- 8 (2 per leg)
- Servos
- DYNAMIXEL XL330-M077-T
- MCU
- XIAO ESP32C3
- Battery
- 2× KeepPower 14500
- Joints
- 692ZZ bearings
Figures as published by the project. See Sources below.
Bill of materials
| Part | Qty | Notes |
|---|---|---|
| DYNAMIXEL XL330-M077-T | 8 | $27.49 each |
| XIAO ESP32C3 (plus one for the dongle) | 2 | |
| Custom main PCB (assembled) | 1 | |
| 692ZZ bearing | 12 | |
| KeepPower 14500 cell | 2 | |
| Printed frames and legs | — | FDM or MJF |
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 $337 as a ballpark from the project. Start at the project repository.
Tools you'll need
- Small hex driver
- PlatformIO
- Python 3
Step-by-step build overview
Electronics & wiring overview
The servos plug directly into the PCB. The only off-board link is the wireless ESP-NOW connection to the dongle.
Software
PlatformIO firmware for the robot and the dongle, plus Python control tools (MIT).
Tips from the bench
- ☕ MJF-printed linkages survive jumping better than FDM ones.
Q8bot FAQ
How much does Q8bot cost?
About $337 in parts.
Can it jump?
Yes. Bounding and jumping are demonstrated.
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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