Wednesday, December 30, 2015

FLL - Trash Trek: Ultrasonic vs. IR Sensor...

As you may know, sometimes the FLL field mat does not quite fit properly on the recommended tabletop. So, in this year’s rules it is stated that, “Slide and align it so that there is no gap between the South edge of the Mat and the South Border Wall, then center the Mat east-west, with equal gaps at left and right.”

With the mat flush against the South Border Wall, a team may be able to use an Ultrasonic or IR Sensor accurately to detect the South Border Wall. 

So, this became a test challenge for the members of the Brics~2~Bots Academy. Brandon assisted in the tests by designing a test robot, writing programs in NXT-G and EV3 to test the NXT Ultrasonic sensor (on an EV3 brick), EV3 Ultrasonic, and an EV3 IR Sensor. We made a chart to record the results.

EV3 brick and software, at Power Levels 20-75, measuring a stopping distance set at 10 centimeters.

NXT Ultrasonic
EV3 Ultrasonic
(less than or equall to)
EV3 IR Sensor -Proximity
(measure in Centimeters)
(equal to)
5.5 centimeters - 20 power 10 centimeters - 20 power 10 centimeters - 20 power
5.5 centimeters - 30 power 10 centimeters - 30 power 10 centimeters - 30 power
2.5 centimeters - 40 power 10 centimeters - 40 power 10 centimeters - 40 power
2.5 centimeters - 50 power 10 centimeters - 500 power 10 centimeters - 500 power
3.5 centimeters - 75 power 10 centimeters - 75 power 10 centimeters - 75 power


NXT Ultrasonic - Seems to work with the EV3, but the response time is off. Measuring for 10 centimeters, it stops much closer and at different distances for the different power levels. See chart. This may be because the response time for the NXT Ultrasonic is slower than the EV3 sensor.

Ev3 Ultrasonic - AT powers 20-75 the EV3 stops accurately. Since the Ultrasonic senses a sound wave that is reflected out to the object; one might wonder, if surrounding sound would have an effect? Testing under noisy conditions didn’t seem to effect the performance of the EV3 Ultrasonic. However, at the  NYC FLL finals at the Javits Center, the noise level is so high that it might cause a problem for the Ultrasonic.

EV3 (IR) Inferred - Used in the Compare - Proximity mode measures in centimeters. AT powers 20-75 the EV3 stops accurately. Since it measures light waves it would not be affected by loud sounds that will be apparent at the NYC FLL finals at the Javits Center tournament.

Note: Power levels above 75 does not allow a long enough response time for the Ultrasonics and IR Sensor to detect an object (however, you could try to push it to 80).

Also, if there is a high level of noise at a tournament, the noise level "seems" to interfere with reading the distance accurately.


Saturday, November 7, 2015

FLL - Trash Trek: The Color Sensor and the Field Mat...

     This year’s FLL Field Mat is of nice quality; teams need to be aware that the high gloss of the mat may cause faulty readings for the color sensors. Depending on the type of light source and angle of that light source, some lighting situations may cause bright reflections on black lines causing the color sensor to read the line as a color value less than black.

Students at Brics~2~Bots Academy ran a test on the FLL Trash Trek field mat, under normal house lighting, to see how an EV3 Color sensor would respond to the mat and this is what they observed…
  1. When line following with one color sensor and using Compare Reflected mode detecting the black line, lighting could be an issue where glare is being reflected off the mat depending on the angle of the lighting. You might get various readings at different parts of the same line. However, using Compare Reflected mode detecting the White bordering the Black line seems to work fine. For those who plan to use Compare Color mode it seems to work fine as long as the robot’s motor power is 30 or less and detects the line at an angle of about 20 degrees; more than that or greater power may cause it to miss or go off the line. For a smoother moving robot (less zig zag) use a power combination of 30 and 10.
  2. When using duel color sensors, the power of the True Value motor can be as high as 40-45, while
    the other motor has a power of 10-20. This allows the robot to move in a smooth straight line.
  3. This year’s mat is very colorful, so when detecting a white line or a black line you need to be aware of the part of the mat the robot has to move across to get to that White line or black line. 
Moving over a light colored area to detect a white line, in Compare Color Mode, the robot might stop or will hesitate over white (duh!) and light colors, but tends to move on to detect the pure white area. 

When detecting black in Compare Color Mode there seems to be no problem as long as the motor power was 50 or less; greater power can cause the robot to over shoot the line; it is moving too fast to have the sensor read and respond to the line.

Moving over dark colored areas to detect a white line, in Compare Color Mode, the robot might stop or hesitate.  When detecting black in Color Mode the robot might hesitate over dark colors and stop on black spots of .5 cm thickness. The thin black lines did not prove to be a problem with motor power of 50 or less. 

When detecting a white line, in Compare Color Mode, the sensor will read light colors mixed in and may hesitate or even stop. 

If you use the Compare Reflected Mode to detect white and moving over a multi-colored area, use GREATER THAN/EQUAL TO the threshold and a motor power of 50 or less. 

If you use the Compare Reflected Mode to detect black and moving over a multi-colored area, use LESS THAN/EQUAL TO the threshold and again a motor power of 50 or less.

It is recommended that teams run similar tests using different lighting situations before you start programing your missions. Note, we did not test the NXT Color sensor, but we suspect that the results would be similar.


Thursday, September 17, 2015

B2B Lab: Our Duplo Pull Toy...

The creative talents @ Brics~2~Bots Academy have made a fun toy for toddlers. It's called the Buggy Pull Toy and it is made from Duplo(R) elements from LEGO(R) Early Simple Machines set and A Growing Caterpillar set. Not only is it fun to build and play with, but it shows toddlers (and some parents) what a gear is and how a linkage mechanism works - early STEM/STEAMThe linkage mechanism gives the illusion of the bug hopping and makes a slight clicking noise (kids love noise)

We submitted it to LEGO Ideas, so check it out and if you like it join and vote for it:

Monday, July 20, 2015

B2B Lab: Animated Mosaics..

What is a mosaic?  Well, it is a design, picture, or pattern that is constructed by putting small colored bits of material onto a surface.  Architectural Mosaics can be made of colored glass, ceramic, or stone pieces, set in a type of mortar or cement. Mosaic art can also be made out of paper, bottle caps, popcorn; whatever.  The size of the pieces used determine the resolution (the fineness of detail that can be seen in an image); the smaller the pieces the greater the detail of the picture.

LEGO mosaics are made with plates of various sizes or bricks attached to a building plate. LEGO Animated Mosaics uses a MinuteBot® baseplate with bricks, plates with holes, beams, pins, and gears to create a design with moving parts. It could be manually operated or possibly be “motorized” with LEGO® Power Functions, if the movement is a continuous motion. It can also be “robotized” with LEGO® Mindstorms robotics.

Here is Olivia’s and Jonas’ Animated Mosaic project is of a Mimon MC and a Two Man Band in a concert.


Saturday, July 18, 2015

B2B Lab: Medieval Castle...

For the Medieval Castle project we did some research on castles from Medieval Times or Middle Ages 450-1500AD and discovered some interesting facts. For example, there was usually a ditch filled with really dirty water around the castle called a moat. The moat served two purposes: one was for defense against enemy attackers because the attackers could not dig under the wall, nor could they get ladders close to the walls, and they would have to swim across, the probably, filthy moat which was often used for the castle’s waste disposal. For the residents of the castle, they were able to cross the moat over a drawbridge. Which brings us to a little physics of simple machines, the drawbridge is an example of a pulley system and the catapult used for flinging rocks, hot metal, and fire balls is a 1st class lever. 

So here is Olivia’s and Jonas’ Medieval Castle…

Olivia, grade 5, wrote this story:

Once upon a time in the land of Lionsville, there lived a king named Mark the II. He had a lot of troubles. The castle needed cleaning, and there was a lack of servants. 
One day he woke up to the sound of battle. A knight rushed in and told the king, “Sir, the skeletons are about to attack and the skeleton king, King Bones (short for Bonsai) has declared war on us. 
Mark the II groaned. There were enough problems already. “Send for the troop,” he commanded! Raise the drawbridge and get the hot water for ready for the Murder Holes.
“Yes Sir!” The knight responded and ran off to make ready for battle.
Finally, after fearce fighting, the battle was won. King Bones and King Mark signed a truce. The castle got its cleaning from the new skeleton servants. 
And all was well at last.

Jonas, grade 3, created a cartoon about the castle, this is part of it:


Saturday, June 27, 2015

B2B Lab: Motorizing LEGO Car sets...

In 2004 LEGO released the LEGO Racers #8652 – ENZO FERRARI and the LEGO Racers #8671 – FERRARI 430 SPIDER in 2006. In 2014 LEGO created a model #10242 of the classic economy car the MINI Cooper Mk VII. All three models are beautiful replicas, however my students, Brandon and Luc, thought it would be really cool if they were “motorized.” So they took the models apart re-designed them to mooooove…

Mini Cooper
Brandon describes how he motorized the Mini Cooper. I built the LEGO®, MINI Cooper model #10242 kit, then I had to take it apart and redesign it a little to mototize it, because I needed to fit the LEGO®  Power Functions (PF) into the car. The LEGO®  Power Functions parts included one M-Motor, one IR Receiver, one IR-TX Remote, and a rechargeable battery box. I had to raise the base of the car to accommodate the motor and the wheels. Then I replaced the back seats with a PF rechargeable battery box and also replaced the engine block with a PF IR receiver. The car was too small to fit two motors in it, so I put the differential gear under the car and for the motor to power the drive wheels with a long axle. With just one motor the car can only move forward and backward.


Luc designed the Ferrai. I used both the LEGO Racers #8652 – ENZO FERRARI and the LEGO Racers #8671 – FERRARI 430 SPIDER models, to create a motorized LEGO Ferrari design. To do this I had to add two Power Function M-Motors, an Infrared Sensor, and a Battery Box to the car. On one side I use gears, so the motors will go in the same way. By using two motors the car would be able to turn. To move the car I used the Power Function remote.

Beeo, Beeo!


Wednesday, June 3, 2015

Book Review: Learning LEGO Mindstorms EV3...

Since the advent of the LEGO® Mindstorms® EV3, manuals about how to build with it and program its robots have appeared in eBooks and printed books. A few are rewrites of previous Mindstorrms NXT books adapted to the new EV3 kit. Then there are a few written from a new perspective and in some cases a little more detail, which is definitely more helpful to the novice Mindstorms builder. Learning LEGO Mindstorms EV3 by Gary Garber, Packt Publishing 2015, is one of those books.

I must say the author has touched on just about everything you might what to know about learning the EV3 system. There are easy explanations and lots of diagrams. So let’s take a look at some of the topics Garber covers…

 A nice feature about this book is that for each chapter there is a brief introductory statement and bullet list of what is being covered in that chapter. So if you are one of those folks (like myself) who does not read a manual from the beginning, you can check out the beginning of each chapter to see if it has the information you are looking for; thank you very much…

 Another nice feature of this book is that the author addresses both the Home and Educational editions of the MIndstorms EV3 kits. Other EV3 books mostly focused on one edition of the kit or the other. In the discussion of Drive Train and Chassiss, chapter 3, examples for a basic vehicle (the author refers to them as a chassis, but to me a chassis is a very basic framework to which wheels, sensors, wires, and other parts will be added to make a working vehicle/robot) is given for both the Home and Educational editions of the EV3. 
Something I have been doing for years when teaching robotics is to have my students maintain an Engineers Notebook; I actually keep on myself when building LEGO Technic® and robots. Now, the EV3 has an Engineer’s Notebook (the Content Editor) included in the software, wonderful! So I was happy to see that the author has a discussion of the Content Editor. He actually devotes a whole chapter on the features and use of the Content Editor, which is excellent.

The chapter on Mechanical Design is very good in that it compares the two motors in the kit, the Large Motor and Medium Motor. It also covers gearing, starting to write a program, and a brief discussion of using (data) wires and parallel threads with nice pictures of examples. Garber mentions the use of the Stop block and that it really is not required, which it not, but when teaching Mindstorms programming to novices is a nice touch and a reference point indicating the end of a program.

The chapter on Sensors covers all the different LEGO® sensors found in both editions, as well as, third-party companies such as, HiTechnic, Mindsensors, Dexter, Verner, etc., which is nice because it lets you know what sensors are found in the two kits and the possibilities of other third-party sensors. Note, only the Educational edition has programming blocks for all the EV3 sensors that LEGO manufactures, including the Energy Meter, Temperature sensor, NXT Sound sensor, and Bluetooth Messaging, but the author does not discuss the programming of these – sigh.

Moving from the basic introductory aspects of the EV3, chapter 5 covers Interacting with EV3; brick buttons, IR  remote/beacon, bluetooth with a smartphone ( a later chapter discusses bluetooth communication between robots), Wi-fi communication, and intermediate programming. After covering image displays, brick lights, and sound output, the author introduces the reader to some advanced programming, data logging, and other programming languages for the EV3. And if you are interested in using the Gyro sensor, there is a chapter on the LEGO Gyro Boy and its programming.
Mr. Garber is a teacher, he teachers Physics and Engineering, and perhaps he is directing this book  to teachers and instructors of Mindstorms robotics and not just the hobbits. This book takes you past the “tutorials” of the LEGO Mindstorms software and accompanying, but limited manual. It helps the teacher/instructor of EV3 robotics understand the system and offers ideas for teaching it. If you purchased the printed book from Packt Publishing, you will have an account, which allows you to download, for free, example code files from the book. If you purchased the book elsewhere (for example Amazon) you can contact: and register to have the files email to you.

Note: On software compatibility, the author states, “As a caution, in version 1.1.0 of the LEGO MINDSTORMS software, Bluetooth communication for the EV3 brick is not compatible with newer versions of Mac OS X.” However, updates have remedy most of the problems except those using Snow Leopard for Mac OS X will experience problems in connecting to Bluetooth. Those with Maverick or above seem to have no problem with either the Home or Educational editions connecting to Bluetooth.

So far out of all the EV3 books I have perused, Learning LEGO Mindstorms EV3 by Gary Garber, Packt Publishing 2015, seems to be the most detailed book on using the EV3, which is excellent for the novice, in particular teachers/instructors, and even former users of the Mindstorms RCX and NXT. I feel the only drawback of the printed book, is that it is not in color. However, you download color images from Packt Publishing: