I've been collecting ideas for building a Mars Rover. This can easily cost a few thousand dollars so I'm not quite sure 
I'm willing to fund such a venture, but it's fun to dream (and plan).

Apparently lots of people have been inspired by the NASA Mars rovers, as there's lots of projects out on the Web. NASA has even created an "open source" robot project, with downloadable plans.

!!! Design Notes

So far I've been scanning the toys at [ServoCity|https://www.servocity.com/motion/] for ideas for the steering mechanism and rocker arms. The scale and weight of the overall robot help decide the size/power of the motors and servos. It's a bit of a balancing act. I also want to, unlike most of the "civilian" designs, somehow tuck my motors inside the wheels or otherwise not have them hanging down near the ground as many/most of the rovers I've seen seem to do. There's a huge impact on ground clearance if your motors are down there banging into rocks and such. The difficulty seems to be locating some suitable wheels. I can't imagine simply 3D printing them, as plastic wheels wouldn't last very long on rocks or concrete. I want a robot that can ''actually roam outdoors''.

! Rocker-Bogie vs. Triple-Rocker Design

The ExoMars (and ExoMy) robot uses a simpler "Triple-Rocker" design.

!! Specifications

I'm going to (initially) steal the specs from the JPL Open Source Rover Project, as a point of reference. Their robot is a bit larger than I'm planning and has an estimated cost of around US$2500, and that's certainly at the upper limit of my budget. But it's a start.

%%(width:80%;margin-left:4em)
||Attribute||Value [[imperial]||Value [[SI]
|Weight|28 [[lbs]|12.7 [[kg]
|Footprint|24x14 [[in]|60.96x30.48 [[cm]
|Battery Capacity|5200 [[mAh]|5200 [[mAh]
|Battery Discharge Rate|8 [[A]|8 [[A]
|Nominal Current Draw|1.2 [[A]|1.2 [[A]
|Operating time|5 [[hrs] (continual use)|5 [[hrs] (continual use)
|Approximate Max speed|68.8 [[in/s]|1.75 [[m/s]
|Maximum 90 deg vertical scale|12 [[in]|30.48 [[cm]
|Maximum height differential between sides|14 [[in]|35.56 [[cm]
|Communication (in this guide)|Bluetooth app (Android only) and Xbox Controller| 
|Cost (*)|~ $2,500| 
%%


!! Links

* [JPL Open Source Rover Project|https://github.com/nasa-jpl/open-source-rover] on github
* [NASA Open Source Rover|https://opensourcerover.jpl.nasa.gov/#!/home]
* [Raspberry Pi Zero or Microbit M.A.R.S. Rover robot £120|https://www.geeky-gadgets.com/raspberry-pi-robot-15-09-2020/], a brief review of 4Tronix [M.A.R.S. Rover Robot for Microbit or Pi Zero|https://shop.4tronix.co.uk/products/marsrover?variant=31848857043059] (there are variants for the Raspberry Pi Zero or Micro:Bit)
* [Yuri 3 rover|https://www.raspberrypi.org/blog/yuri-3-rover-the-magpi-82/] (The MagPi #82), describes the Yuri 3 mini Mars rover, which was designed by Airbus engineer John Chinner
* [Build your own NASA Curiosity rover|https://www.raspberrypi.org/blog/build-nasa-curiosity-rover/] from the Raspberry Pi Blog 
* [Students Can Now Build Their Own Rover Model|https://www.jpl.nasa.gov/news/students-can-now-build-their-own-rover-model] (JPL)
* [NASA, Raspberry Pi and a mini rover|https://www.raspberrypi.org/blog/nasa-raspberry-pi-and-a-mini-rover/], built by NASA scientist Dr. Jamie Molaro with an estimated cost of US$5333
* [Robot Garden’s Mars Rover|https://forum.makeblock.com/t/robot-gardens-mars-rover/13520]. a 3D-printed robot (YouTube video also [available|https://youtu.be/WmEvipAQbeU])

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[{Tag MarsRover}]