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Intermediate build

How to build Sawppy the Rover

10-DoF six-wheel rocker-bogie rover · Intermediate

Sawppy is Roger Cheng's rocker-bogie Mars rover model, built from 10 LewanSoul LX-16A servos, 23 printed parts and 15 mm extrusion. MIT-licensed, about $500.

Start the buildProject files
Difficulty
Intermediate

Some soldering, calibration and Linux comfort needed.

Build time
2–4 weekends

Our estimate, part-time

Parts cost
$500

About $500, per the author's estimate

Degrees of freedom
10

MIT

What is Sawppy the Rover?

Sawppy is Roger Cheng's model of Curiosity and Perseverance, with the same six-wheel rocker-bogie suspension. JPL's Open Source Rover inspired it, but Sawppy cuts the cost a lot.

Instead of gearmotors and RoboClaws, it uses ten LewanSoul LX-16A serial-bus servos (six drive, four steering), printed connectors and Misumi HFS3 15 mm extrusion.

The repo documents Sawppy V1 with STLs for all 23 printed parts, print and assembly guides and a parts list, all MIT. The editable CAD is on Onshape.

Sawppy the Rover specifications

DoF
10 (6 drive, 4 steer)
Servos
LewanSoul LX-16A
Frame
Misumi HFS3 15 mm extrusion
Compute
Raspberry Pi 3
Battery
2S 5200 mAh LiPo

Figures as published by the project. See Sources below.

Bill of materials

PartQtyNotes
LewanSoul LX-16A10
LewanSoul USB BusLinker1
Raspberry Pi 3 + SD + 5 V regulator1
2S 5200 mAh LiPo1
Filament≈3 kg
Switch, voltmeter, fuse—Misc. electronics
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 $500 as a ballpark from the project. Start at the project repository.

Tools you'll need

  • FDM printer
  • Hacksaw for extrusion
  • Hex drivers

Step-by-step build overview

Electronics & wiring overview

All ten LX-16As share one serial bus through the BusLinker to the Pi, powered by the LiPo through a fuse.

LiPo batterypower sourceLaptop / PChigh-level controlEncoderssensingRaspberry Pireal-time controllerServo bus adapterdrivers / bushobby/smart servos10 joints / motors
PowerData / commandsSensor feedbackOverview only. Follow the project's own schematic for pinouts and voltages.

Software

ROS 2

Python rover control (MIT), originally SGVHAK rover code.

Tips from the bench

  • ☕ Set each servo ID one at a time before chaining them.

Sawppy the Rover FAQ

How much does Sawppy cost?

About $500.

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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