Sawppy the Rover was inspired by JPL's Open Source Rover project. Most of the differences between Sawppy and its JPL inspiration were motivated by a desire to reduce cost and complexity. JPL's rover is designed for education, to be assembled by a school team and give a robust foundation for structured curriculum. Sawppy is more suited for individual hobbyists like myself who are happy to tinker and willing to make some trade-offs to lower cost.
The budget was $500, and getting there required the following changes:
- Motorization: Instead of using gearmotors with encoders managed by RoboClaw motor controllers, moving the wheels will be done with serial bus servo motors.
- Construction Method: Instead of using the Actobotics construction system, Sawppy will be built from Misumi 15mm 3-series aluminum extrusions beams connected by 3D-printed plastic parts.
These two major design goals can be summarized as: Servo Actuated Wheels, Printed Interconnect For Extrusion. The acronym SAWPIFE led to the nickname "Sawppy".
See the "Links" section for pointers to additional information:
- Live Onshape CAD file: This is where I'm tweaking and building Sawppy in full public view. Be warned the live file has upsides (latest ideas!) and downsides (latest idea doesn't work!)
- Github: This is where the assembly instructions currently live. It also has a snapshot of Sawppy components in STL file format. These parts may lag behind the live CAD data, but they have been printed, installed, and proven to work on my rover.
- Build Blog: The history of Sawppy, including stories of design goals and lessons learned from failures.