SMART Meeting

1. SMART Meeting April 26, 2008 David Schilling

2. Crate Contraptions

3. Crate Contraptions • We’ve done about 10 public Crate Contraptions since September 2002 • Robots cooperate on a large field, moving crates and or balls around • Extremely fascinating to watch • Time intensive to put together a set up • Not very forgiving

4. Getting More Participation • Several times we’ve asked others to add robots • But results have been mixed • Robots have to be 100% reliable • Any robot not working means the entire display effectively stops • Time commitment is fairly steep • often requires a dozen or more nights

5. New Idea • SMART-Bot City

6. SMART-Bot City • Kicking the idea around for a number of years • Requires an enormous amount of space • Requires a way to detect/avoid other traffic • NXT allows this to happen

7. SMART-Bot City • A network of roads • Streets • Intersections • City blocks for robot ‘destinations’ • Each robot communicates with a master to coordinate traffic

8. Benefits • Robots can enter and leave the display without everything grinding to a halt • Can have many different groups of activities at once • Crate robots • Ball robots • Anything else they want to do • Even just driving around

9. Difficulties • Robots still have to drive accurately • Lost robots will cause problems • Communications might be a difficult problem

10. Streets and Intersections • Streets are ¾” wide black tape • There are silver strips across the tape marking important locations

11. Important Locations (silver tabs) • Intersections • Locations of buildings • Street segments

12. Streets • In general streets are two-way • But there’s only one strip of tape! • A street will only ever have one robot on it at a time • Having a robot on a street forces some streets to be temporarily one way

13. Street Dimensions • Roads are considered 12” wide – that’s 6” on either side of the tape strip • Intersections will have slightly more maneuvering room, but only slightly

14. Traffic • Each robot connects to a master • Communication is of the form: • I want to go to destination X, what’s the next step to get there? • I’m about to enter the next intersection/street segment, may I proceed?

15. Traffic Rules • Destinations are always on the right • All intersections are at near 90-degrees • Two straight segments • A 90-degree turn • A ‘T’ intersection • A 4-way intersection

16. Master Traffic Cop / GPS • Could be a bunch of NXTs tied together • Each NXT can only talk to 3 other NXTs • Will be expensive to do this way • But it will be an “All LEGO” display

17. Master Traffic Cop / GPS • Could be a single PC with multiple Bluetooth dongles (need to test this!) • Can talk to many NXTs at once • Everyone has a PC, should be easier to get a display working at anyone’s home • Not “100% LEGO” – might be a disappointment to some • Can show map on PC’s screen – might increase interest

18. Robot Responsibilities • Robots must fit size restrictions • Must be able to maneuver and turn in spaces provided • Must be able to track line very well • Must be able to handle rough surfaces • Must obey Master Traffic Cop / GPS

19. Robot Needs • A single light sensor to follow line and detect silver markers • Approximately ½” above surface • Some shrouding • BT enabled communications • Have an easy way to change batteries • Two motors for driving • Either differential-steer or rack&pinion

20. Robot Flexibility • There’s a motor port left for whatever you want • There are three sensor ports available for whatever you want

21. Robot Programming • Core navigation / communication code will be provided • Line tracking code included • Will likely have to tweak it for your robot • You specify steering system at compile time • Your code will call functions to do what your specific robot needs

22. Problems • Area required will be HUGE! • Cost of surface might be prohibitive • Any ideas?

23. Benefits • Almost anyone can participate • We’ll provide navigation code for your robot, so you only have to supply robot-specific code • Just a tour-bot will work, and indeed add something to the display • Easily scalable • Error tolerant

24. Benefits • Doesn’t take days or weeks to prepare in advance • We can make it a public standard, other groups can participate in our displays or create their own

25. Crate (or other) Contraptions • For those ambitious: you can build a set of cooperating robots and or destinations • It’s up to you to decide how your set of devices work • The communications standard might be augmented to know about crate or other object inventory locations

26. Next Month’s Mini-Challenge • Build a Tour-Bot for SMART-Bot City • Start at your home garage • Request permission to enter road • Drive around randomly for a while • Request a random destination • Ask for instructions how to get there • Get permissions for streets/intersections • Return to your home garage

27. Remember the rules • All destinations are on the right • This includes your garage when you get there • You might want to position your robot so it starts as if it had just pulled in • Make sure you can handle the maneuvering restrictions

28. BrickCon 2008 • First weekend in October • Seattle Center • October 2-5 • We’ll show our Indy 5.00 robots • We’ll put on our first public display of our new SMART-Bot City