The Ev3 R3PTAR model
Pretty scaring close up of the R3PTAR robot when ready to bite!
Pretty scaring close up of the R3PTAR when it’s ready to bite!

Here comes the R3PTAR (read Reptar), a slithering snake that can bite you! 🙂

If you own the Lego Mindstorms Ev3 retail set, you surely know this one. The original building instructions from LEGO can be found here.

This robot features three actuators: one Ev3 Medium Motor and two Ev3 Large Motors. One large motor drives the robot forward or backward, while the other one can rapidly sling the snake open mouth toward the “victim”. The medium motor instead swings the robot neck  to the left and to the right, so giving the snake the ability to slither and to change direction.

I’ve chosen to build and program the R3PTAR because I wanted to try to codify a mission:

  • Mission Phase 1: roam to find a victim (well, actually a victim improbably wearing the IR Beacon);
  • Mission Phase 2: chase the victim;
  • Mission Phase 3: when you’re close enough, give the victim three rapid bites.

And the R3PTAR must slither, of course!

The Ev3 R3PTAR model
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