Archive for January, 2012

I have gotten a ton of emails lately about how to follow a line with an NXT. I decided to build a bot to show off some of the easiest ways. Using twin light sensors and a LineLeader from Mindsensors, this robot shows 3 possible ways to complete that task. First, it can use a single light sensor and a simple threshold to follow the line. This method proves to be slow, but effective. Next it uses two light sensors to move forward and correct if one sees the black line. Finally comes the Mindsensors LineLeader which uses 8 light sensors and a control theory called PID to follow the line. As we add more light sensors and more complex control, the robot moves faster and more smoothly. Check out the bot and video below!

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Brickbot

Posted: January 21, 2012 in LEGO
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Baz, an MCP up in Montreal, Canada, created one of the coolest robots ever, Brickbot. Brickbot is a LEGO MINDSTORMS robot, hidden under a big LEGO shell. For Christmas/my birthday, my roommate got me a few LEGO containers. Like Marc, I quickly made a robot to fit inside the shell. Using parts from only one NXT kit (but some may be different in color), I created the frame you see here. I put in a ultrasonic sensor that looks under the bigger brick to help it avoid objects. I wrote a quick program in NXT-G and my red Brickbot was born. He roamed around at the Greenfield Brick Expo and will be roaming around today at the IL FLL State Tournament in Chicago. More pictures below!

I decided to do some work on the LEGO MINDSTORMS Space Shuttle. As some of you may know the orbiter’s mass alone is close to 5 kilograms. (Imperial units, that is about 11 pounds!) This puts a huge amount of stress on the gear boxes that drive the motion of both the Canada robotic arm and the rocking of the orbiter itself. Every 3 months or so, I have to take the shuttle apart and inspect or fix the gear boxes. The arm Baz built has been clicking lately, but I have discovered that is just a torque issue (too much in this case). I can fix that in software. The bigger issue is the gear boxes John built. They eat LEGO, literally. Check out the picture of the parts that I removed from the gear boxes. Those are half module bushings that have been eaten away.Yikes!

Also, special thanks to my brother, Anthony. He sent up his nice Nikon camera in preparation for my trip to Australia next month. It takes beautiful pictures!

This past weekend was the Greenfield Brick Expo in Greenfiled, Indiana. It was a great event with over 7,000 square feet of LEGO creations. I was out with several robots, including the LEGO MINDSTORMS Space Shuttle. The booth always had a crowd, but I was able to capture these before the beginning of the second day. Check out the pictures from my booth at the event. This next weekend I will be in Chicago at the Illinois State FLL Tournament! I will be bringing much of what you see here, plus a few more.  If you are in the area, stop by!

Do you see any new robots?! I will have a post later this week featuring some of my newer designs.

Happy New Year! 2012 is here and I have some new code to celebrate the holiday!

The Dexter Industries dWifi sensor has opened up a whole new world for LEGO MINDSTORMS. For those of you who have looked at the sensor, you will notice it requires that a “newline” character (decimal 13). The dWifi also likes each byte to be sent individually. To cope with these requirements, I have posted a block that does all the work for you. As you can see from the screen capture on the right, there is a simple loop to send each byte (including the newline byte added to your string). The file is posted and is live now on the Files page of my blog. You can use the regular Set Speed and Read VIs that come with the RS485 2.0 download.

Stay tuned for more dWifi LabVIEW and NXT-G updates!