The horse shoe crab from Fay Rhodes' "One-Kit Creatures"

Some weeks ago I built a customized version of the horse shoe crab from Fay Rhodes' great book "LEGO® MINDSTORMS NXT 2.0 One-Kit Creatures". Today I have taken the time to produce a small video on it:

A Plethora of Pressure Sensors

It used to be there were very few ways to sense air pressure with the NXT… but over time a number of different companies have come out with third party pressure sensors for the NXT. It’s something that I’ve been interested in for a while: I’ve used pressure sensors for determining altitude during hikes, monitoring high-altitude balloon flights, technical geyser investigations, and lots of other things… so it seems natural to try to compare some of the sensors currently out there in the NXT market. Warning – this is my own personal testing and opinions. It may be wrong. And in the interest of full disclosure, most of these companies have been extremely helpful to me by providing sensors to test and responding to feedback… but still, this is as closeas I can come to an unbiased position. I have pressure sensors from four companies currently: HiTechnic, Vernier, Mindsensors,and Dexter Industries. All of them interface easily with the NXT, using NXT-G blocks, NXC code, or other drivers. Most of them (all except HiTechnic’s) can be “plugged in” to an air line like the LEGO pneumatic tubes or standard aquarium/sized tubing, which is handy for a lot of things. For this I tested all of them under NXT-G 1.0, and used whatever way seemed best to get the highest resolution readings I could from the sensors (sometimes using manufacturer-supplied blocks, sometimes reading the sensors in a “raw” format, etc.). So, without further ado… here we go.

A comparison of four sensors all on the same NXT, attached to the same manifold. I could pump air in and out using a pump based on a large syringe with two one-way valves. First the pressure was reduced (you can see the individual pump cycles in some cases) and held low, then the seal was broken to bring the pressure up as rapidly as possible, before the same pump was used to increase the pressure.

A detailed graph of the very first depressurization event, showing how the four different sensors respond to a sharp change in pressure. The Dexter Industries sensor was not involved in this test (due to software issues), but was tested and is described below. Notice how the Vernier Barometric sensor (purple line) stops dropping even as the pressure continues to be reduced, "bottoming out" at the lower end of its range.

Dexter Industries dPressure250 and dPressure500:

http://dexterindustries.com/Products-dPressure.html

Cost: $28 for the 250 kPa version (up to 30 psi), $32 for the 500 kPa (70 psi) sensor.

Response time around 1 ms, analog, stated resolution of 250 Pa, although this varies across the range slightly (sensor reads all the way down to at or very near 0 kPa). The only true differential pressure sensor, with two ports (one for “negative pressure”, one for “positive pressure, clearly labeled”), this is the only sensor that can do an on-the-fly comparison of the pressure in two separate systems of tubes (if you want to build a Pitot air-speed sensor, this is the sort of thing you want. Non-linear response really makes it easiest to read this with the stock NXT-G blocks (but I couldn’t do this under NXT-G 1.0, this was not tested equally to the other sensors here). The 1/8th inch ports are easy to use (if small for some uses). This sensor reads fastest of all in this review, as it is can be read as a simple analog sensor (with a light sensor block, for example) once every 7 ms, although the sensor seems to have a longer physical lag time than that so it is not “really” as fast… but it’s still faster than any other sensor it seems. The biggest drawback may be the low pressure resolution… while fast, this isn’t as detailed as the other sensors here. The dual ports however are a unique feature that may be exactly what you need in some cases. Some care needs to be taken with the bare circuit board design style, but the sensor element itself is well mounted and I had no worries about it breaking off.

Vernier Gas Pressure sensor:

http://www.vernier.com/products/sensors/gps-bta/

Cost: $83, (but you need to use $39 Vernier adaptor as well, potentially making this a $122 sensor)

Very fast response (purported to be 0.1 ms, but there’s no way to verify this on the much slower NXT). Reads from about twice atmospheric pressure all the way to zero (range of 210 kPa to 0 kPa), with a measured resolution of 240 Pa (note that Vernier lists a much higher resolution almost 5000 times better… but this isn’t available using the NXT’s internal analog-to-digital ability). Damaged above 4 Atm (60 psi or 405 kPa), this is a sensor that can handle high pressure and give you reasonable accuracy, considering the range. As an analog sensor, can be read as fast as any other (about 7 ms in my testing set up), but using the Vernier stock blocks it takes slightly longer at around 9.5 ms. The provided tube rapidly twist-locks to the sensor, and has a good valve and a universal adaptor at the end common to chemistry and physics departments (almost certainly the best supplied tubing set-up of the bunch, a feature shared with the sister Barometer sensor below). While the sensor housing is bulky, the long cables (this is an analog sensor) allow it to be used in a variety of situations… although for exactly the same reasons, using Vernier sensors with small mobile robots tends to be a problem. The very linear response, and high speed of this sensor are fantastic… but you certainly have to pay more for that. It should also be noted that there’s a reason for the higher cost… the Vernier sensors have very high resolution compared to the others here, but Vernier has never come out with a stand-alone AtoD converter that would allow the NXT to access this. I keep wishing; a basic 16-bit AtoD reader would make these (and a host of other analog sensors) potentially much higher resolution, really justifying (for NXT users) the higher cost. Does anyone at Vernier read these J ?

Vernier Barometric sensor:

http://www.vernier.com/products/sensors/bar-bta/

Cost: $71, (but you still need that $39 adaptor, making the effective cost perhaps $110)

Again, very fast (on the order of 1 ms) response time. Almost identical to the Vernier gas sensor in look and function, but with a higher resolution (and more range-limited) sensor inside (everything I said for the cables, form, and tubing supplied with the Vernier gas pressure sensor holds for this as well). Instead of reading from zero to a high pressure, the sensor is limited from a lowest reported pressure around 84 kPa, to a highest reporting pressure of about 121 kPa… but that means over that range (about 80% of normal pressure up to 120%) the resolution is much better, around 25 Pa (again, it could be better… Vernier claims this sensor has resolution at the level of 1 Pa or so, but you can’t get this with the NXT’s lower resolution AtoD conversion). This comes with a caution – the sensor can be broken if subjected to more than around 2 Atm (203 kPa) pressure, so this is not a sensor for high-pressure environments… but for detecting small rapid changes at or near normal pressures, it’s hard to get better than this, period. Again the tubing kit, valve and adaptor are superior, and very handy. This is probably my most frequently used pressure sensor… but I must admit it comes with a large pricetag (note: this is one of the sensors I had to spring for myself… and even at the over $100, I’ve never regretted it. Your mileage may vary).

Both these Vernier sensors require an adaptor to interface with the NXT:

http://www.vernier.com/products/interfaces/bta-nxt/

Cost $39

Bulky with a long cable. Not for compact mobile robots, but used with all Vernier sensors, so you can at least swap it in and out of different experiments (i.e. – no need to get one with every Vernier sensor you own… you just need one for each port that’s going to be hooked up to a Vernier sensor. And Vernier has… a lot of nice, unique, sensors).

HiTechnic Barometer NBR-1036

http://www.hitechnic.com/cgi-bin/commerce.cgi?preadd=action&key=NBR1036

Cost: $55

Very slow response… while the sensor can be polled rapidly (once every 16 ms or so), the response to changes in pressure (as can be seen on the graph) is much much slower... not in 10’s of milliseconds, but in tens of seconds! Actually, for a barometric sensor, designed to respond to slow changes in pressure, this is the sort of response you want – the sensor is averaging out all sorts of short-term changes & noise to give you the best estimate to the true, ambient, weather-related pressure. On top of this the sensor also returns the ambient temperature (the only one in this review to do this), so in a real sense this is a “two for one” sensor, still taking only one sensor port. It is also fairly high-resolution, returning the pressure at a 10 Pa level (as HiTechnic claims, and is demonstrated by testing), better than any of the above. It can do both these things because it is not an analog sensor, but a true digital sensor, retuning information to the NXT via the I2C interface. On top of this the NXT-G block has been designed to make it very easy to interpret the pressure changes as elevation changes, making this the most transparent “digital altimeter” available as well. The next time I go hiking and want to log my elevation changes… this is likely the sensor I’d turn to. The casework is the standard high-quality HiTechnic model, LEGO-certified and indistinguishable (except for a small label) from any other LEGO sensor. For fast responses, this isn’t the sensor to get, and it can’t be easily connected to a tube or pipe to measure those sorts of pressures (the only one without a port of some type, probably related to being LEGO-0certified in LEGO-certified casework). But a really nice sensor for weather & altitude related measurements.

Mindsensors PPS58-Nx

http://www.mindsensors.com/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=150

Cost: $40

Rapid response, about 16 readings a second… but testing reveals that it will actually read the sensor much faster than this, returning a cached value off the sensor until a new updated pressure reading is available internally. So, what’s the “real” response time? If you are worried about how long reading the sensor “stalls” your program, it takes only about 16 ms… if you are worried about how fast this sensor can report a change in pressure, the answer is closer to 60 ms (about 16 times a second). If you are worried about how fast mechanically the sensor system responds… it’s even a little bit slower than this. If you look at the response comparison, you can see that this sensor takes some time (about a second) to reach the new pressure during a sharp change. So the “real” response time here really depends on what you are curious about… a common problem when discussing things like sensors. The sensor measures from 0 up to about 58 psi (0 to 400 kPa) very nicely, but as an I2C sensor this one, like the HiTechnic version, can have a high resolution: by reading the raw sensor output, it can actually measure the pressure to about the nearest 2 Pa (not exactly like the 1 Pa resolution mentioned in the website… but still amazingly high resolution, and it may have been due to how I was reading the sensor). In more common terms, it can detect a change in atmospheric pressure of just 0.002%, (equivalent to determining a change in depth beneath the ocean of a tiny 1/5th of a millimeter!). This is a ported sensor, and is packaged using the Mindsensors now-standard “doubled circuit board” approach that protects the components inside while making a very strong “sandwich” structure that’s perhaps more robust for damage (note: I’ve always worried about static damaging these exposed sensors… but I’ve yet to have it happen. Perhaps I worry too much). For the highest-resolution measurements on the NXT, this seems to be the best sensor available, and while not the fastest response, it’s a close fourth behind the three-way tie for first in this review.

The Conclusion

If you’ve bothered reading this far, you probably want to simply know “which should I buy”. So, here’s your answer:

I don’t know.

I’ve tested these sensors and used them in a lot of different ways. In robots, altimeters, weather stations, and physics experiments. Weighing objects, determining water depth, and analyzing how a balloon inflates. Each of these sensors has strengths and weaknesses, and which you want really does depend on what you need it to do. Do you need the least expensive (Dexter Industries is the lowest cost option on the market right now)? The fastest (Dexter Industries or Vernier sensors)? High-resolution that’s got a response of a few milliseconds (Vernier)? Ultra-high precision (Mindsensors)? Pressure & temperature at the same time, in one compact sensor (HiTechnic)? Something else? If you want the right sensor for your application… you first have to understand what your application is.

Swarm robots

Robot swarms are an area where LEGO® MINDSTORMS NXT could fit in very well. However, they sadly have played a very minor role in the NXT universe so far.

Here's a great inspiring video on a 4 year swarm robot  research project that connects a couple of (non-NXT) robots from different European universities:

NXT camera dolly

Whenever I made images and movies of my NXT robots previously, I always have been unsatisfied with the quality of my recordings. Hence, I decided to build a stable camera stand to avoid at least wiggly images. Of course, as a NXT builder I ended up not with a simple stand but with a programmable camera car on rails (which is, as I learned, in lingo called a "camera dolly"):

 

I am still lacking the skills to produce such excellent robot movies like some of my NXT colleagues; but at least I might be able to make some with smoother tracking shots now.

Debugging with the NXT screen: Displaying numbers

If you're a programmer like me, your programs won't work perfectly when you run them the first time. Sometimes it's a simple mistake on the programmer's part, but sometimes the problem is not so obvious.

In some cases you can analyze part of your program by displaying some of the program's variables on the NXT screen. For example, you can do this to determine whether a sensor works or not.

Displaying such a number on the NXT screen is not very difficult, but it can be a bit cumbersome if there's multiple things you would like to display. To make it a little easier I'd like to share an old trick (a My Block) that will make it simple to do this.


The NXT screen will show "Sensor: 47" if the ultrasonic sensor measures 47.

Installation Instructions
- Just open the packed example program:

Click here to download. Be sure to open it with the Mindstorms software, not as a zip archive! Alternatively, use "Right Click" and click "Save as" first. The My Block is included and will automatically be added to your other My Blocks.

Using the block
- Run the example to test your block and try it out. (Then just skip the info below).

- Use the "Number to Display" setting to specify the number you would like to display. You would normally supply the value through a Data Wire as in the example.

- "Text Line (0-7)" specifies on which line the number should be displayed. 0 is at the top of the NXT screen, 7 is at the bottom.

- "Text (Optional)" lets you optionally add some text to the number. This is useful if there's multiple things you want to display on the screen. For example, putting "Sensor:" in the example results in "Sensor: 47" on the NXT screen if the value is 47.

- The block will always erase the text line in question before showing something new, but you can check the "Clear Screen (Yes/No)" to empty the whole screen if necessary.

---

Update: Steve Hassenplug reminded me of a custom NXT block (Not a My Block) that he made that does just the same (find it here).

Whether you want to use this block or the My Block is up to you. Steve's block can nicely be added to your other Action blocks, right next to the Display Block if you wish. The My Block on the other hand is easier to share because the person you share it with does not have to install a custom NXT block.

RobertaLAB | CAD Animation

Cool CAD animation of the Roberta Ant included in Roberta Series 1 - NXT.

158 parts to make this ant designed by A. Green 

I: /. 7.

NXT yoghurt opener

Nice little NXT device by pasquentmax that opens a typical yoghurt container. I'm sure you could adapt the approach to a bunch of other food packaging.

 

Google gives back - to NXT

Every year around Christmas Google sponsors with 40 million $ some projects around the globe in areas that are close to the heart of the company: education in science and technology, education for girls, promotion of technology and projects against human trafficking and modern slavery.

In 2011 gone by, there was a NXT-based project amongst them!
The German project Roberta is an initiative by the Fraunhofer Institut that aims to promote interest and education of girls in science and technology by using LEGO® MINDSTORMS NXT.

The NXT STEP that has now and then blogged about Roberta in the past wishes to compliment Roberta for that achievement and acknowledgment of its great work.
Cudos!

The Dynaway Sorting Plant

From the guys who brought you the C5 NXT Blimp, have a look at this awesome industrial color and size sorting plant commissioned by Dynaway. This model is used to demonstrate their manufacturing execution system.

It sorts 2x4 and 1x2 bricks in size and color. The bricks get sorted directly into pallets in a high bay storage system. When a new color is detected, an empty pallet in the high bay storage is assigned to the color. When a pallet is full, a robot retrieves it, and returns a new empty pallet. 

There are 7 NXT’s in the plant, and they all communicate with each other and a PC application over Bluetooth. The software written in leJOS, with is a java language for MINDSTORMS®.


Full details can be found on the BrickIt  team's website

Skype Car - Follow up statistics

Leon have just finished his initial Skype Car experiment and followed up with some great statistics.

Here is the original post we published - http://thenxtstep.blogspot.com/2012/01/skype-controlled-robot-yes-you-can.html

He kept it running for a 2 weeks and got people from all over the world connecting in.

• 700 people having a go
• Average 4 minutes per connection
• Over 20 countries

Get the full run down of statistics from his latest post -
http://worldofmindstorms.com/2012/01/18/skype-car-lots-of-numbers/

Congrats Leon, can't wait to see what you do next!

NXC tutorial in Portuguese

A good new for the Portuguese followers of the NXT STEP!
The NXC tutorial I originally wrote with John Hansen back in 2007 has been translated
also in Portuguese. Divirta-se!

MINDSENSORS Touch Panel Library for LejOS

The advanced users of the NXT could be happy to know that I wrote
the library to easily manage all the features of the NXT Touch Panel sensor device by MINDSENSORS. It is available from the Lejos SVN repository and in the next release of LejOS NXJ.

Google Science Fair 2012

Google has announced the Google Science Fair 2012, the largest Online Science competition in the world which takes place in partnership with The LEGO Group, CERN, National Geographic and Scientific American.
Any youngster between 13 and 18 years, either alone or in teams up to for persons, can take part and hand in his or her Science project, presenting it on its own Google web site.
At the end, the best projects will be awarded with great prizes.



At the first Science Fair last year, over 7500 projects were handed in from 90 different countries, with a lot of LEGO® MINDSTORMS NXT amongst them.
Take part!
This is how you enter:

Lesson plans from Dexter Industries

Dexter Industries (who makes all kids of cool NXT sensors) has just submitted a few lesson plans / ideas to http://www.k12lab.com (an part of National Instruments who created NXT-G in conjunction with LEGO)

So far they've submitted lessons for:

Thermal Infrared Sensor (TIR) -Measuring Heat from a Laptop exhaust fan -
http://www.k12lab.com/lesson-plans/Monitor-Computer-w-NXT-TIR

and their Solar Panel - Constructing a Solar Car
http://www.k12lab.com/lesson-plans/NXT-Solar-Car

They've included sample programs for LabView for LEGO Mindstorms (LVLM), but even if you're not using that language, you could adapt to NXT-G or any other one.

NXTAVATAR a Tele-presence robot

The NXTAVATAR  is a Tele-presence robot which is visually remote controlled using the internet.

It is easily build. You need: a LEGO® MINDSTORMS® 2.0 set, an iPhone® 4 (or other Smartphone) with Skype® installed, a Windows PC with Skype® installed, 2 Skype® accounts and 2 NXTAVATAR programs (which are open source). You can download building instructions & NXTAVATAR programs at www.nxtavatar.com. You can easily adjust the robot and programs to fit your own demands.
Have fun!



Below are the controls as seen on the PC side, The frame in red is what is shared on the mobile device via Skype screen sharing.

Features
- Remote control using the internet
- Face to face interaction
- Full audio & video communication
- Moves forward & backward
- Turns left & right
- Looks up & down
- Gets & drops small objects









It was created by Andreas (NXTwallet) the father of the first transformable NXT WALL-E, and a good friend of mine, I was thrilled when he asked me if i wanted to try his NXTAVATAR!!!  He lives in the Netherlands but thanks to his new LEGO Mindstorms robot, i was able to visit his house, meet his family and play with his dog bobby ;) 

Here is me, bazmarc, on the NXTAVATAR thousands of miles across earth!!!

NXT + HMI/SCADA interface

Leistungsfähiger Panel PC für Standard-Industrieanwendungen by Green_Mamba
Attribution-NoDerivs License

SCADA (supervisory control and data acquisition) is a robotics system that is found in factories and industry around the world.  It takes in sensor information from sensors and then coordinates processes to make things happen.  Think BMW's car factory as the chassis are moved from workstation to workstation.

COPADATA is a company the specialises in SCADA software and they have put together an interface with the NXT.  This means you can program in any of the IEC 61131-3 languages (typical SCADA programming languages) and then run the code on a NXT device.  This sounds like a great way to test out your code before putting it out onto multi-million dollar industrial robots :)

You can write programs that interface with the motors and all standard sensors as well as Gyro, Accelerometer and Compass.

I haven't had the chance to give it a go (you need to order their free software DVD), but it certainly looks like a great way for universities / colleges to teach SCADA with low-cost hardware.

http://www.copadata.com/index.php?id=1838

Thanks to Olov who brought this to my attention!

Huge mobile robot arm

One of our readers Aris just sent through this enormous robot arm he has been working on.

It manages to lift a cup of water (heavy glass, not light plastic!) off a table, and then follow a black line through the house setting the cup down on another table.

Some quick specs

• Total weight: 4.2kg
• Maximum load: 1kg
• 7 Motors (NXT and PowerFunctions)
• 1 NXT
• 1 RCX
• Pneumatic Gripper

Fantastic work Aris!

Usage of NXT at the NASA

On brickengineer.com, there's a nice online article today on the usage of LEGO® MINDSTORMS NXT for prototyping at the NASA: the KnuthLab LEGO Exploration Rover developed by the Knuth Cyberphysics Lab acts

"as a testbed for robotic intelligence and navigation software", 

as the page states.

Read the full article here.

Skype controlled Robot (yes you can drive it!)

One of our readers Leon just sent me through this amazing project he's been working on.

He has built an NXT robot that you  (yes you!) can control over Skype.  It's set up to work between now and January 18th and I'm just had a great time making it cruise around Leon's setup.

How it works.

• You make a call to Leon (details at the bottom of the post)
• You share your screen with Leon
• The Webpage has 4 buttons (forward, left, right, stop)
• Each time you click a button, your screen changes to a different shade of grey.
• A NXT with light sensor at Leon's end picks up what colour you have (because you're sharing a screen) and then transmit via blue tooth to the NXT robot what to do.

Leon has a great writeup on his blog with lots of technical details on how he achieved it.

http://worldofmindstorms.com/2012/01/04/interactive-skype-controlled-mindstorms-nxt-car/

Hopefully we'll get an update from Leon when it's finished with some stats about how many people connected, what the average length of connection was etc!

My Wonderful Steam NXT

During the days around New Year, I have performed a finger exercise in LEGO® MINDSTORMS NXT Steampunk: the Wonderful Steam NXT. It can be built with a single NXT 2.0 set and three Rotacaster® wheels:



A Rotacaster® wheel allows for movement in two directions; they are produced and sold by the Australian Rotacaster® company and compatible to LEGO®.  For the Wonderful Steam NXT, Rotacaster sponsored three of them (Thanks, Rotacaster!) , which enables it to turn on the spot.

I like these wheels a lot - they are reliable, very useful for building holonomic mobile robots (have a look at previous posts on our blog for further examples of NXT robots equipped with them) and last but not least look cool.

Update: Building instructions for the vehicle can be found on my web site.

NXT biped from China

Here's a new great biped walker created by the team of the Chinese NXT blog cmnxt.com:



Some more pictures can be found here.

LabView for LEGO Mindstorms

Along with the popular NXT-G and NXC(RobotC) programming languages there is LabView for LEGO Mindstorms (LVLM).  Those who played with RoboLab in the RCX days will find it very familiar.

Rob Torok spent some time at Tufts University working with LVLM and has put together a series of great tutorials to get people up and running.  For those of you possibility hitting the limits of NXT-G, LVLM is certainly a good step up in capability.

Here is the first tutorial and you can see all of them here -https://sites.google.com/site/robtorok/lvlm-tutorials/



More info about LVLM here - http://www.k12lab.com/products/NI-LabVIEW/

NXT-ified LEGO Crane

Loyal reader Justin Chan just sent through his conversion of the LEGO Technic 8421 model 2.  He's done an excellent job and by the looks of it has crammed a lot in such a tiny space.  It still has all the original functions of driving, steering, rotating / lifting/ extending the boom arm and even lowering the ground supports.

Looks likes he's got the Mindsensors Motor Mux to get all 6 motors to talk to the 1 NXT onboard.

The whole thing is controlled by another NXT connected via bluetooth.

All this from a secondary school student.  Well done Justin!

NXT Bowling alley

Not the most intricate of constructions but I love how the pins are reset, so clever!



via @dexterind

*** UPDATED ***
A much more refined version using the same priciple - Thanks Philo!!

Top NXT creations for 2011

So here it is..... The most popular NXT creations for 2011 (as determined by pageviews from our amazing readers!)

#5 - UNIMOG NXTification by Anika

http://thenxtstep.blogspot.com/2011/08/unimog-nxtification-by-anika.html

#4 - CubeStormer II: A NXT machine that solves a Rubik's Cube faster than any human

http://thenxtstep.blogspot.com/2011/10/nxt-machine-that-solvesa-rubiks-cube.html

#3 - MindCuber: Build a Rubik's Cube Solver with a single NXT 2.0 set!

http://thenxtstep.blogspot.com/2011/11/mindcuber-build-rubiks-cube-solver-with.html

#2 - LEGO® MINDSTORMS digital clock

http://thenxtstep.blogspot.com/2011/10/lego-mindstorms-digital-clock.html






And the most popular creation (with double the pageviews of #2) goes to....

#1 - Amazing Mindstorms 3D printer

http://thenxtstep.blogspot.com/2011/08/amazing-mindstorms-3d-printer.html




Which was your favourite?  Let us know in the comments!

Countdown for Possible NXT Tool on Kickstarter

The NXT comes with a nice collection of sensors that most Mindstorms fans, kids and adults, have figured out. Most anyone who has spent any time tinkering with NXT robots has figured out how to use the Touch, Ultrasonic, Sound, and Light sensors among others. You build your robot, program it, and run it... and watch the results, whether it's avoiding walls, following a line, or catching a ball.

But as with most NXT robots, the robot is typically running while you're in the room, so to speak. Many have designed robots to automate certain tasks while the owner is away, but it's not the norm. Yes, our NXT robots are autonomous, but they more often than not require a human presence close by to monitor the action. For anyone wanting to give their robot real autonomy and an ability to communicate with its owner no matter where that owner may be... well, that's been complicated. Yes, you can do it, but it often requires some serious electronics skill to wire up a separate circuit that can communicate via Twitter or maybe posting data to an HTML website. What's been needed for a while is the ability for our NXTs to let us know what's going on when we're no where close by... maybe even on the opposite side of the globe. Imagine wanting to build a small NXT device that detects when your bedroom door is opened (or closed) using a Touch sensor or maybe the Ultrasonic sensor and alerts you with a text or email message. Again, not so easy to do with a basic NXT kit.

Until now.

If you've got a nice collection of sensors for your NXT, you might be interested to know that a new Kickstarter project has a device that's being funded (with your help) that will allow your NXT to communicate with you via email, text messaging, and a few other options. It's called Twine, and it's a small, battery operated device (waterproof, too) that has a built-in motion sensor and temperature sensor. You configure the "rules" for the sensors using an online, cloud-based application the Twine team has created called Spool.

Let's consider the idea I mentioned above -- a detection device that lets you know when your bedroom door is opened. You'll first want to build a robot that will detect that door being opened using maybe the Touch or Ultrasonic sensor. Easy enough. But here's the trick -- you'll also want to build a small, flat bed on your robot that will rock left or right when the door is opened. On this bed you'll place the Twine device that you've configured to send you a text message (or an email) when the built-in motion detector is triggered. How easy is that?

Twine developers are busy creating a number of other sensors that will be able to be plugged into the basic Twine device, but you'll also be happy to know that they're offering a breakout board add-on that will allow external sensors to be wired in -- you probably won't want to break open your NXT sensors and expose the wiring, but... you can. With the breakout board, I imagine someone would be able to easily wire Mindstorms sensors directly to the Twine device.

But if you prefer not to open up your sensors, the Twine device by itself offers up lots of options:

1. Use the Light sensor and the previously mentioned "flat bed" to trigger the Twine when the Light sensor detects a light being turned on and get a text message sent to your phone.

2. Use the Ultrasonic sensor and "flat bed" to trigger the Twine's motion sensor when the Ultrasonic sensor detects the food level in your dog's bowl is too low. When it gets low, you get an email saying "FEED ME!"

3. Want to know if your little brother or sister disturbed something in your room? Put it on top of a Touch sensor that triggers a slight movement of the Twine and have a Tweet sent to your Twitter account telling the world "My nosy brother/sister just picked up my guitar."

As the Twine team releases more and more sensors (a few are already in the works, including an IR sensor) you can expect the Twine device to open up a lot more options for your NXT robots to communicate with you while you're away. Yes, the NXT isn't doing the actual communication, but if you've built a solid robot that can trigger whatever sensor (motion, temp, IR, etc) is connected to the Twine, you can rest easy knowing you'll get a text or email or Twitter message letting you know that something has occurred while you were away.

Now, the basic Twine is $99... not cheap. But then again, neither is the NXT. If you've been looking for a way to give your NXT robots a way to "talk" to you when you're not around, this is definitely one of the easiest ways to do it. At the $115 level of backing, you get the breakout board... higher levels provide you with additional sensors. But the basic Twine at $99 will automatically provide you with temp and motion sensors built into the actual device.

Now here's the bad news -- the Twine Kickstarter project only has 17 hours left as I write this... less by the time you're reading it. They've already raised enough money for the device to be built and shipped, so all that's left is to get more backers who want to get one (or more) before the time expires. The team hasn't said when the Twine will be sold to the public yet, so this may be your only chance to grab one without having to wait a long time. Delivery of the Twine device is estimated to be in March 2012, and I've already got my backing in place to grab one (with the breakout board).

I'll be interested to hear what others think they might use the Twine to do in collaboration with an NXT robot.

You can read complete details of the project here as well as watch some videos.

NXT High Noon Duel

Quoting Back to the Future II:
Marty McFly: [showing the two boys how to play the shoot 'em up video game] I'll show you, kid. I'm a crack shot at this.
[shoots a perfect score with the electronic gun]
Video Game Boy #1: You mean you have to use your hands?
Video Game Boy #2: That's like a baby's toy!
Well, this is not at all a baby's toy! That's the kind of projects I love: simple, and effective!

You can challenge yourself, measuring your reflexes, or play with a friend,
to see who is the fastest. You can build it and program it
using the material the author shares on his website.
REMEMBER! Guns are not toys at all. Play safe, play well, play with LEGO!

A subjective NXT retrospective to 2011

2011 is drawing to an end, and it's a tradition to have a look back at this time of the year. With THE NXT STEP, the focus of such a retrospective naturally is on LEGO® MINDSTORMS NXT; so I thought about my very personal annual highlights in that regard.

It was an amazing NXT year, to be sure!
After being 5 years on the market now, instead of cooling down LEGO® MINDSTORMS NXT seems to gain even more momentum every year.

Hence, there are a lot of candidates for "The NXT Model of the Year 2011", and most likely everyone will have his or her very special favorite.
As for me, I did not have to ponder long over the one I personally like best:  the outstanding Blimp of the two Danish NXT dudes Lasse and Kenneth (see left). A great project, even more when one had the privilege to face it "in realiter" (as it was granted to me at WRO).

From there, it is not far to my very personal "NXT Photo of the Year 2011"; it shows Lasse helping an Arab boy controlling the Blimp at said WRO in Abu Dhabi - a photo that in my opinion notably conveys the spirit of LEGO® MINDSTORMS NXT.

(©  by bazmarc

So, what's your personal "NXT Model of the Year 2011"? Or your "NXT Photo of the Year"?
Tell us!