Sherman the Lego RCX Tank at RoboGames 2016

After getting my old Lego RCX Mindstorm kit working again, wanted to see if I could make a fighting robot out of it. Since robot tanks are kinda my thing, it was an obvious design choice for 'Sherman'. Borrowing from some recent projects, the basics driveline design was inspired by the Lego IR Tank, and the rest of the design came from the RCX tank tests from last year.

The final design for Sherman:

Main power was two Power Funcitons Large Motors driving the front sprocket of each tread.
Auxillary motor was a single Power Functions Medium Motor, that applied power to a differential, and the power traveled down a series of gears and ultimatily applied power to the middle sprocket of each tread. The idea was suppose to be that this mechanism could provide extra push when Sherman is attacking, but generally didn't interfere with the movement of Sherman.
Front mounted light sensor would detect the edge of the fighting arena, and allow Sherman to avoid driving off the edge.
The RCX IR transmitter transmitted IR signals out, and the forward facing light sensor detected reflected IR if an object was close. Then Sherman would go into attack mode, all three motor going full power.

Leasons Learned

The 18 year old RCX based robots have long left sumo competition, we got lots of comments of people saying it was cool to see one.
Sherman was underpowered, couldn't even budge the other robot.
Sherman was really under weight. I was so worried about taking a large design and scale it down for the sumo rules, I didn't pay much attention to weight except to make sure it didn't go over 1kg (it was like 600g).

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