PID Controller and the NXT

Fellow MCPer Philo emailed me this link to a tutorial involving PID controllers and NXT (written by James Sluka)... take a look and let us know what you think.

It's got some math (not too heavy) and some very good discussion on robot control.

Don't lose your head, drive safe!

The schools started again, and the UK this PSA ( UK: Public Service Ad) for the cycling safety organization Biking Rules, a little yellow Lego fellow takes a massive hit in the name of raising awareness about riding through a red light.

He’s lucky – he can reassemble himself and carry on about his business, which is fortunate as he’s a reckless idiot. However you, dear reader, are not made from Lego. So be careful out there.



Martyn

Fellow blogger gets some attention

He would never toot his own horn... so I'll do it for him! Congratulations to one of our bloggers, Jonathan Daudelin... out of over 1000 NJIT freshman students, he was picked as one of the freshmen this article focuses on.

Way to go, Jonathan.

Manty, third bonus model NXT 2.0 (8547)

Proudly we announce the third bonus model for the NXT2.0 box. Laurens Valk (blogger at this blog) and creator of various interesting walking models has designed a praying mantis “Manty”. This model shows up next to Morph on the back cover of the box.

The model has a touch sensor to automatically synchronize its legs and an ultrasonic sensor to detect your hands, so it can avoid you.

Enjoy building

Martyn

new NXT blog

From reader Chris S.:

I want to announce my new Lego NXT blog, www.tinkernology.blogspot.com. My goal is to show several of the techniques I have learned over the 20 or so years that I have been building with Technic and Mindstorms.

I have started my blogging with a project that I think is really great. It is a system that uses the HiTechnic IRLink sensor and some PF motors to control several air valves. Basically, it is a cool way to control up to eight pneumatic valves with one NXT using only one port.

Are you Linkedin?

Anyone using Linkedin might want to check out a new group for LEGO Mindstorms Enthusiasts and Fans. It is hosted by Martin Alvarez Milan, a curriculum developer and owner of Robots4Kids.

Minimalistic remote control for the NXT

When using Philo's great NXT joystick remote control for my basketball-playing NXT robots at Fana'Briques in June, I noticed that the very young users had some difficulties in getting along with it (in particular due to the size and the problems they had with understanding how to manage turns). So for the SteinCHenwelt LEGO® event ten days ago, I decided to come up with a more simplified one that met the reduced requirements of my soccer robots that debuted there.
The result was the rather minimalistic Remote Control No 3, a Bluetooth-based NXT remote control that uses the four buttons on the NXT Brick itself to control the movement of a remote NXT robot (forward, backward, left, right).
The two attached touch sensors can be optionally used to trigger special functions on the controlled robot (in the case of the soccer robots, it was kicking the ball).

At SteinCHenwelt, the gamepad-oriented style of the remote control and its comparatively small size went down well with the youngsters (you can see its usage in the SteinCHenwelt movie).

Remote Control No 3 is a good option when you do not need to control the actual speed of the remote robot. For the SteinCHenwelt, I programmed it with leJOS NXJ, the Java platform for the NXT (the programs can be downloaded from the associated page at my NXT web site); however, writing NXT-G programs for it should not be that difficult, also.

Snow Leopard issues - an interim fix

There have been a number of people who have had problems with the NXT-G environment installations, and the newest Max OS 10.6 (Snow Leopard). Installations that either don't work or don't seem to do anything, etc. There is a interim solution I've been told about, but I've not personally tested it, as (for various reasons) I've not installed 10.6 on my Mac as yet. But, here's the steps I've been told should allow NXT-G 2.0 to install on a 10.6 machine:

1. Copy the contents of the installation CD onto the Desktop
2. Open the copied folder and look under "Parts". Under Parts, location the "MindstormsUnivEdu.pkg" (if you are trying to install the Educational version) or "MindstormsUnivRet.pkg" (if you are working from the Retail install CD).
3. Control-click (or right-click, if you have a two-button mouse) on the package, and choose "Show Package Contents" from the pop-up menu. This allows you to poke about in the normally "sealed" installation package.
4. Go into the revealed Contents/Resources directory and delete the "preflight" file (toss it in the trash)
5. Close this package and then run it like a normal install from this modified version on your desktop. Mindstorms NXT should install properly.

This is not by any means a permanent fix - LEGO and NI are working on that, and hopefully will have a patch or something to fix this properly. But hopefully this will allow the folks who have had trouble with 10.6 and NXT-G to continue playing.

Please let us know if this fixed your 10.6 problems, or brought up new ones.

NXT 2.0 "Gadget of the week" in Ireland

gadgetrepublic.com, "Ireland's top source for gadget news and reviews", has selected the LEGO® MINDSTORMS NXT 2.0 kit its "Gadget of the week", stating that "robot hobbyists" were

"the reason for the existence of Lego's 'NXT' iteration of Mindstorms kits back in 2006 as their enthusiastic 'modding' inspired the advanced 'build your own robot' gear".

Nice to hear. :)

Read the complete article here.

Guest Blog - Team Robo Boogie

From David C. in New Zealand:

The boys in the team are primary school students, ages 10 and 11, and they had lots of fun creating and running these robots over a period of about 3 months. The robots used Mindstorms NXT and a Rainbowduino (Arduino) board for the robot face and matrix display. They won the Primary Dance part of the competition.

SteinCHenwelt 2009: the Movie

Last weekend, the SteinCHenwelt 2009 LEGO® event took place in the Swiss Technorama Science Center at Wintherthur, Switzerland.
Here's the movie I made about it; though I could be present on Saturday only, it was worth the journey to Switzerland.
Also the NXT 2.0 soccer robots performed quite well at their first mission.

NXT Combination Lock Box

It's been a while since I have posted something fun for the original NXT, as I have been distracted by NXT 2.0 recently... So here is something fun. This Combination Lock Box keeps the blue and red balls locked inside until you enter the correct combination using the dial wheel and Enter button, then it will unlock and open automatically. The first time you run the program, it will ask you to set your combination of three numbers, then it will remember this combination even when the NXT is off and only open the box when the correct combination is entered.

The building instructions and program are for the original NXT, and it is not buildable as designed here with NXT 2.0, but maybe some NXT 2.0 users will give a try at modifying it. The program should work on NXT 2.0 (like all NXT 1.X programs).

Here is a video of the box in action:

NXT Wii Bowling robot

If you're anything like me, you enjoy the Wii bowling game, but haven't quite mastered how to bowl the perfect round.

Never fear, the guys over at BattleBricks have your solution!


One motor presses the 'A' button and the 'left' to setup up the perfect line. It then swings right around to press the 'B' trigger button on the back of the Wiimote. The other motor swings back and then forward, and the 'B' button is released at exactly the right time.

More info including the program used and building instructions can be found at
http://www.battlebricks.com/wiigobot/

--
Damien Kee

Sept 11

We will not forget.

Article on Dean Kamen invention

The Slingshot isn't new - it's been seen on TV and Kamen has talked about it quite often, but this article indicates that the time is nearing for it to be put to actual use in the world.

During a very brief meeting at World Fest in 2008, I suggested to Dean that he consider putting a challenge to every FLL team (or FIRST robotics team of any sort) to raise money to purchase one Slingshot for donation. Of course, I didn't realize at the time that these machines cost well over $100,000 each... but with manufacturing methods and some improvements, according the article the price should drop to around $2000 per unit. That price is certainly within a reasonable range for FLL teams to consider doing fundraisers (or partnering with other teams to sponsor a Slingshot).

What do you think? FLL is such a great competition, and it gives students an opportunity to show their technical stuff... but how about asking teams to try and help focus attention on the lack of clean water in many countries by raising money during FLL season to "buy" a Slingshot?

Next weekend: SteinCHenwelt event in Switzerland

Some weeks ago, we posted some announcement for the SteinCHenwelt already.
On next weekend, the 12^th and 13^th of September, it finally will take place in the Swiss Technorama Science Center in Wintherthur, Switzerland, hosted by the Swiss LEGO® Users Group.
Next to a lot of LEGO® stuff there will be also some NXT robots attending, including a GBC and a soccer pitch where the visitors can match against each others with two remotely controlled NXT 2.0 robots (created by me).
And, of course, questions can be dropped to the present NXT experts (including three MCPs).

The event will start at Saturday 9:00 AM and last until Sunday around 5:00 PM.

A very special feature of the SteinCHenwelt is the possibility to inspect and try out the fantastic gadgets of the Technorama also in the same run - and that is always worth a visit!

NXT Path Measurer

FLL season is upon us again, so I decided to post a tool that FLL teams (and other NXT users) may find useful. This Path Measurer project for NXT 1.0 and for NXT 2.0 gives you an easy way to plot and measure a path for your NXT to travel, so that you can quickly determine how many degrees to use as the duration for your Move and Motor blocks, for the portions of your navigation that use "dead reckoning".

Hopefully this will save teams some time on this more tedious task and give them more time to spend on something else, like learning how to use sensors. As most teams knows, the degrees needed for segment durations depends on the actual robot used (wheel diameter and spacing, etc.), so it is best to determine this by experimenting with your actual robot.

Mechanically, the Path Measurer is just a touch sensor on a wire, which you can hook up to your robot (any robot using the normal 2-motor drive) and use it as a wired remote control to guide the movement of the robot by remote control when you are measuring the path using the programs provided. You select the type of movement for each segment of your path using the NXT buttons, then press and hold the touch sensor to drive in that direction. The NXT screen will read out the degrees travelled by the motors for that segment, which you can then record and have your teammate type into the configuration panels of your Move and Motor blocks of your autonomous program. This should be much faster and more accurate than rolling the robot by hand and using the View Motor Degrees feature of the NXT (or just using trial and error).

The NXT 1.0 and NXT 2.0 versions are essentially identical, except that the 2.0 version uses the newer Rotation Sensor blocks, which behave slightly differently: In 2.0, a rotation sensor will report negative degrees for "backward" movement, whereas in 1.0 you get positive degrees in both directions.

Color Sensor not allowed in FLL

For any FLL teams using the NXT 2.0 kit, note that the color sensor is not allowed in the FLL competition. The FLL rules allows for up to 2 "Light Sensors", and this refers to only the original NXT light sensor or the older RCX light sensor. The Color Sensor is not allowed, even if you only use it in "Light Sensor" mode. I verified this with FLL to be sure, and they confirmed. So if you have the NXT 2.0 kit, you can buy the original NXT light sensors separately from LEGO Retail or from LEGO Education.

"Smart Move" FLL Resources - TechBrick

TechBrick has posted some new items for download for this season's FLL challenge, Smart Move, including movies, summaries, and scoring sheets. Check it out here.

Google Teachers—

Teachers, check out the Google group, legoengineering. It's moderated by Damien Kee.

NXT 2.0 Five Minute Bot

Sometimes you need a basic robot vehicle that you can build quickly in order to run some experiments, or whatever. This Five Minute Bot for NXT 2.0 can be built very quickly, but it still has good basic driving and turning performance on smooth surfaces (not designed for carpet), so it should give you reasonably pure experiment results.

This design is a variation on the NXT 1.0 Five Minute Bot project I posted last year, and although this one is designed for NXT 2.0, it can also be built with NXT 1.0 retail (8527).

I hear that many FLL teams have found the 1.0 Five Minute Bot design useful for their teams to experiment with, for example, to start learning programming and driving/navigation before the team has designed their own robot, or just to get off the ground if they are having trouble getting started.

Product Demo LEGO store Oberhausen

Today (Saturday 5 Sept 2009)

Come to the LEGO store in Oberhausen for a product introduction and demonstration, of the NXT2.0

the Address is:
LEGO Store im CentrO
Centroallee 228
Shop C 125
D-46046 Oberhausen
Germany

Martyn

Robotic Events in NZ

I do not normally blog about local events related to MINDSTORMS NXT here in New Zealand. However, given the increasing NZ readership the NXTStep has now, I thought I would mention some exiting events coming up. If you are in New Zealand and of school age and have access to a NXT kit, then this should be of interest to you:

First one is this Saturday:

The teams will be competing for trophies in Robot Rescue, Robot Dance and Robot Soccer.

More details (including registration info / costs etc.) in here.

I spoke to Mildie Meyer-Els from Toshiba (sponsor) – who has been working really hard getting everything organised. She is expecting big things this year. With over 100 teams competing on the day (of which 55 will be competing for the Auckland titles and the rest competing against the Auckland winners for the national Competition in the afternoon), this should be an exciting event tomorrow. I will certainly be there – feel free to twitter me at the event if you want to meet up.

---

The second one is still three months away - but if you are interested you should register ASAP:

FIRST (For Inspiration and Recognition of Science and Technology) is quite a well known robotics competition held in the U.S, and many international teams compete every year. However, this is the first time schools (and individuals 9-16) can take part in FLL in NZ.

More details (including registration info / costs etc.) in here.

I also spoke to Jason Kyle from Kiwi FIRST who is organising this pilot event. They are expecting about 26 teams working on challenges that transform the way we look at transportation. Jason told me that the trust has made available some loan MINDSTORMS NXT 9797 sets for schools that are new to robotics. They have also structured the fees differently from other parts of the world to make it more affordable for schools with multiple teams from same school who can practice with the same challenge set.

If you are in NZ, and you are into NXT robotics - please get involved: If you are of school age, you can talk to your school about taking part (if you are not already). If you are an adult, consider volunteering to do some mentoring with the kids and help out with your local schools. Trust me - it is great fun!

Tim

Guest Blogger - Home Automation

Reader Koldo sent the following:


My 16 years old son and me, we have done a project using Hitechnic Experimenter's kit and 9795 set (Intelligent Building Set). The goal of the project was the automation of a house. My son has used and adapted some circuits he found in the Experimenter's kit handbook.

The construction is the model anyone can find in the set instruction's book but he has added to the model one temperature sensor, one magnetic sensor, one LDR and some LEDs. The circuit is built in a solderless breadboard, is a fast way to build it, and easier than start learning soldering.

The model has the following features: The ventilator start running when the temperature go down; the ligths turn on when the light sensor detects the lightness go down; if the sound sensor that is inside the house detects the noise go up the sistem activates the alarm (lights and siren); the door can be opened with a magnet and the system opens the garaje door when it detects a car.

I've used RobotC for the program, is a program with several tasks, and we had some problems with NXT-G 1.1. The program is in my website http://lrobotikas.net and the translation into English here (http://translate.google.es/translate?hl=es&sl=es&tl=en&u=http%3A%2F%2Flrobotikas.net%2Fes%2Fmodelos%2Fnxt%2F92-instalacion-de-vivienda).

NXC Tools for Mac OSX

John Hansen, the author and maintainer of NXC, the C-style programming language for the NXT, has now published a set of tools for the NXC development on Mac OSX.
NeXT Tools is

"a universal binary Mac OS X application which provides many of the tool windows that are part of the Bricx Command Center IDE. Included are: Direct controller, Diagnostics, Watch, Piano, Joystick, Remote, NeXT Explorer, NeXT Screen, Messages, Memory Map, Clear Memory, MIDI Conversion, Wav->RSO, Find Brick, Turn off brick, Close communication, and Firmware download",

as John states on the site from which the tools can be downloaded for free.

Nice stuff for Apple users!

Free Robotics Workshop at Wichita State

On Saturday, September 19, 2009, WSU’s College of Engineering will offer a free robotics workshop to parents and teachers who are interested in coaching a robotics team to compete in the 2010 Shocker MINDSTORMS Challenge on March 6, 2010.

The workshop will be held on the WSU campus in the Engineering Research Building Lobby from 9:00am-3:00pm. Steve Smith, who has coached a robotics team for the last 8 years, will introduce attendees to the LEGO NXT equipment and software, and talk about his experiences in forming a team and preparing them for the competition.

Robotics kits and laptops will be provided for the workshop. Space is limited and registration is required. Registrations will be accepted on a first-come-first-serve basis, but preference will be given to individuals interested in starting a robotics team, or expanding a current robotics program in preparation for the 2010 MINDSTORMS Challenge.

A flyer you may print and distribute to anyone interested is located at the website.
A link to the online registration form can be found at: www.wichita.edu/shockermindstorms/Workshop2009

Article on Geekdad on NXT programming options

geekdad has published a new article on the NXT where the author announces his plans to "explore its capabilities" by trying out some of the programming options out there for it.
Though I do not understand why Mr. Olsen dismisses Java-based options from the start (he gives no reason for it), while I am considering for instance leJOS NXJ as one of the best, mature, structured and easy-to-use programming platforms for the NXT out there and am using it regularly, the article nevertheless provides a nice overview.

I'm curious to hear about geekdad's further experiences with some of the options listed there.