The Mk.2

For the past few months I have been working on my second version of a mini-magellan rover. The first version I built was too large to comfortably fit in my Jeep, so I had to downsize a bit. The Mk.2 is a three wheeled “tail dragger” robot that uses proportional skid steering.

Rover Mk.2

Rover Mk.2

This pic gives a good overview of the robot. My design philosophy for this ‘bot is overkill, durability, and reconfigurability. The main body is 1/2″ Pine, with a nice coat of stain and a few coats of polyurethane. Building the body out of wood is easy, cheap, and gives the ‘bot a funky retro look. Plus, if things go horribly wrong, I can recycle it into a breadboard or something. 🙂

Durability: I expect this robot will be encountering some rough terrain as it does it’s job, so durability is a priority. I am using terminal strips and connectors for everything so nothing bounces loose. The motors are kiddie car “PowerWheels” motors from a local surplus store. The 12v batteries were intended for use in a UPS, but another local surplus store (Gateway Electronics) had them on sale for $10. Everything is bolted and lock nutted, and this thing is strong enough for me to stand on.

Overkill: The 12v batteries are wired together for a longer run time. I would like to get an hour out of each charge, but that has yet to be tested. The PowerWheels motors are designed to haul around a small kid, and are designed for kiddie abuse. The wheels/tires are utility tires from Harbor Freight, and are rated at 300 lbs. of load each. The handheld GPS is far more powerful than I really need to drive a mini-magellan course, but it has some nice features that might come in handy later.


Reconfigurability: One thing that I have found is that things change on robots. A new sensor, different batteries, new motors, etc. I don’t want to be locked in to a particular setup, so everything can be easily disconnected and reconfigured. Terminal strips and connectors make it easy to access the pins on the microcontroller, 12v power, sensors, etc.


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