Thursday, December 31, 2009

Freaky Cool Off-Road Vehicle

Now here is an off road vehicle with all the bells and whistles.  He put tons of effort into the user interface with a great realistic dashboard.  Absolutely incredible.

What, no heated seats???  You're just not trying hard enough.

Tuesday, December 29, 2009

My Favorite From 2009

Thank you from the bottom of my heart for following my blog in 2009.  It's been great fun for me to bring you Tinkernology.  I plan to keep bringing you cool stuff in the future, but I can't do it unless you guys keep building stuff so keep it up.

My favorite post from this year was the stuff that superbird28 posted back in 2008.  I looked back and I realized that I missed possibly the best of his creations.  For your viewing pleasure... Brickline 1

Monday, December 28, 2009

Robotic Glockenspiel

I just love this...

Saturday, December 26, 2009

More Robots and Lego

Mitsubishi is the latest company trying to make children obsolete. *sigh*

Friday, December 25, 2009

Angled Beams

Have you ever wondered why these beams are at an angle of 143°? More precisely, 143.1301°.

It’s a good question, and I wondered for a long time as well. Then I discovered why, and it's actually pretty simple. It’s because of the Pythagorean Theorem. You know,

I discovered it while I was building a long truss, much like this one.

If you look closely at this simple truss and count not the holes but the hole spaces. The hole spaces are the length between the holes. For example, if you have a nine hole beam, there are eight spaces, a fifteen hole beam, there are fourteen holes spaces, etc. When you count them up, you'll find you have a common 3-4-5 right triangle.

Remember that the Pythagorean Theorem only works for right triangles, so the formula works out to be

3^2 + 4^2 = 5^2
9 + 16 = 25

I know that once I figured this out, life got much better and I began to use these oddball beams a whole lot more often.  The 3-4-5 right triangle is very useful in engineering and especially useful in building with Lego. I have used it several times, and I hope to share some constructions with you soon.

Merry Christmas

I hope all of you woke this morning in this fashion.

Tuesday, December 22, 2009

Robotic Prank

One underutilized function of robotics is the good ole’ prank. There’s nothing like a robot with a hidden surprise. I have a few in mind that are pretty simple but effective.  Here’s a video that’s not a gut buster, but certainly a light chuckle.

Monday, December 21, 2009

High Bay Warehouse at LEGOWorld 2009

I have been waiting a long time for this video, and it just leaves me wanting to see more.

Absolutely incredible.  I WANT MORE VIDEO!!

Friday, December 18, 2009


Want a good, extremely challenging Free Lego Technic game to play over the holidays? Check this out!  It's called Cogitate.

Note: My security software returned this note;  “In our tests, we found downloads on this site that some people consider adware, spyware or other potentially unwanted programs.” There is also other feedback from others saying they had no problems, and I had no problems. I have my security set pretty high.

Here’s another Lego game that I found fun too. It starts out pretty easy, but over 40 or so challenges, it gets harder. It's called Lego Junkbot.

Thursday, December 17, 2009

iPod-NXT Analogy

I caught this photo recently of the developers of Lego Mindstorms at work.  The banner in the background really caught my eye.  I am interested in knowing your thoughts whether or not Lego has achieved this or if they ever will.

Two Motors-One Rotation Sensor

As I mentioned several times before, I really like the PF motors. I like everything about them except the fact that they don’t have built-in rotation sensors. So I thought long and hard about how to incorporate the old RCX rotation sensor into the drive wheels of a bot. I am not crazy about using up the input ports with RCX rotation sensors. The idea I came up with is to read the rotation of two motors with a single rotation sensor.

(Click to Enlarge)

I did it by running a chain from the driving axles of each wheel back to the axles of the differential gear. Then the outer gear of the differential gear turns the rotation sensor. As each wheel turns, the rotation of the driving shaft is transferred back to the sensor through the differential gear. There is no power “leakage” from one wheel to the other because the rotation sensor easily turns and doesn’t transmit through the differential. The lightweight chains can be used because the power transmitted is very small. I ran it around the floor some and it seems to work.

Pretty nifty, but interpreting the sensor output takes some thought. First, when both wheels are turning, the readings are twice as fast as if only one wheel is turning. This is because of the nature of the differential gear. Not really a big deal as long as the programming takes that into account. Second, if the wheels are turning in opposite directions as in a “zero radius turn,” the reading will not change because the axles on the differential gear are turning in opposite directions. Again, you have to take that into account with your programming. Third, if both motors are turning at different speeds, the reading doesn’t make sense. I think that this condition can be avoided most of the time. So for a general reading of straight forward and reverse, left and right, this crude solution should work just fine.

I like this solution for a few reasons. It means that the driving wheels can be controlled by the NXT and the HiTechnic IRLink. You will have used only two input ports while leaving three motor ports open for other tasks! They can also be controlled by the IR remote control although the sensor readings won’t make sense. So you have an intelligent robot that can drive itself and you also have a robot that you can drive remotely without making any hardware changes.

Wednesday, December 16, 2009

Children Are Now Obsolete.

There is finally video of the Motoman robot assembling Duplo bricks at IREX 2009.

Tuesday, December 15, 2009


There is a growing group of people who are buying and building a scratch built 3D printer called MakerBot.  The technology is based on Stereolithography which is “is an additive manufacturing technology for producing models, prototypes, patterns, and in some cases, production parts.” (Wikipedia)

Basically, it is a computer controlled machine that builds parts out of material by adding several layers over and over until a 3 dimensional “thing” is produced. It’s pretty cool stuff and it is becoming more and more popular among scientists, engineers and professionals. It used to be very expensive and not many people knew how to use it. With the popularity and ease of use of many 3D solid software packages and off-the-shelf electronics, it is becoming much friendlier to the hobbyist. The MakerBot retails for under $1000.

In fact, some futurists believe that one day, rather than going to the store to buy certain things, you can go to your machine and “print out” what you need. That technology is far off in the future, but here is an example of someone using their MakerBot to create Lego pieces.

Here's a video of the machine in action.

And now a word from our sponsor....

Monday, December 14, 2009

Incredible Festo

I have to give it to Festo. They are really thinking outside the box on their creations. Check all these out and you will see what I mean.

First of all, Festo BionicTripod mit FinGripper. It resembles a parallel robot.

Then there’s the CyberKite. Just in case you have become too lazy to go fly a kite.

But don’t forget the Festo Molecubes...

And then finally, the Air Ray.

There’s more too. Just go to the FestoHQ channel on YouTube.

Sunday, December 13, 2009

Game Idea

I was sitting around tonight thinking about the really cool game that is showcased on  They have built a Guitar Challenge Game based on the very successful game Guitar Hero.  My idea is pretty rudimentary, but I think it could be a great start to some cool game development.  It is based on the game that started it all, PONG

The unique part of the game is that it can be played with more than one person and more than one NXT.  Using a little bit of algebra and the Bluetooth capability, two people (or more) could battle each other.  I have conjured up my best MS Paint skills to illustrate the idea.

I am a builder and not so much of a programmer, so I thought I might share this idea with the hope of inspiring someone.

I should have known.  Somebody has done it already.

RobotC Cool Projects

The guys over at RobotC have created a page where they showcase some cool projects that have been programmed in RobotC.  One of them looks vaguely familiar to me..

Saturday, December 12, 2009

Philo's Fast Ball Sorter

Philo has made me smile. He has created a ball sorter that is very fast, very accurate and very smooth. He threw in some cool linkages to boot. Give it up for the expert.

Friday, December 11, 2009

Cool Coasters

Here’s a crazy thought. Adult’s spending lots of money on a kid’s toy and making really cool stuff.

Thursday, December 10, 2009

Don't Be A Jerk and a commercial

OK, so I have two kids under five years old, so needless to say, I get to watch lots of cartoons.  Nickelodeon has played two versions of this video.  The Lego version is by far better.  And I tell ya, when you hear this song several times a day, it sticks.

On the same note, Lego has started running this commercial.  I have been in this position...exactly.

Mechanical Art

This is not Lego related, but it is certainly inspiring.

MechanicalSculptor has several short Kinetic art videos on YouTube

Wednesday, December 9, 2009

Lego Stewart Platform

Here is my version of a Stewart Platform. Stewart platforms have applications in machine tool technology, crane technology, underwater research, air-to-sea rescue, flight simulation, satellite dish positioning, telescopes and orthopedic surgery. (from Wikipedia).

It is powered by six medium PF motors with six linear actuators and three IR receivers. It is controlled by a single NXT with the HiTechnic IRLink. My version doesn’t have any feedback, so the motors linear actuators are turned on and off based on time. It took a few hours of research to get the linkages and joints down, but once I did that, building and programming took only one night.

Movement is sloppy because of the PF motors. I want to try to build this using servo motors, but mounting the huge motors is a problem.

Here is what a well built Stewart Platform should look like...

Sunday, December 6, 2009

HiTechnic Sensor Multiplexer Review Part 2

I spent the weekend messing around with programming the SMUX in RobotC. It was pretty intimidating at first, but after I found the sample programs and the drivers found on the HiTechnic web site, it was just a matter of spending some time staring at the code.

The first thing I found was Xander Soldaat’s “HTSMUX-Tutorial-LATEST.pdf” file found linked on the HiTechnic site. Reading this file actually scared me because it gets into the internals of the SMUX. This document does little more than confuse the lightweight programmer, but if you are a heavyweight, this document is for you. I am not a programmer, so I just look for the easiest way to use the code and hardware.

Then I downloaded the RobotC Drivers and Examples found on the HiTechnic downloads page. I spent some time looking at the SMUX examples and felt a heavy relief. All of the hard core programming has been set up in drivers, and the sample programs do a great job of showing how to access and use the drivers. Xander has done a great job of making the sample programs easy to understand. All of the programs are very similar, so switching back and forth for different sensors is pretty easy once you figure out his methods.  There is also a great video showing how to set up the drivers so they can be easily accessed within your RobotC programming environment.

The only real problem that I encountered was some of the timing issues. I hooked up four sensors; an acceleration sensor, an ultrasonic sensor, a sound sensor, and a light sensor. I put them all in a loop and took readings from all of them every 50ms and had great success. The problem that I encountered was initializing a couple of the sensors. I tried to set the light sensor in both Active and Inactive modes (light on and light off). I found that I had to put a 200ms WAIT statement after changing the mode. If I didn’t do that, the light wouldn’t respond and the previous mode would be used. No big deal, but it took some work to figure it out. The sound sensor has a mode selection of dB and dBA. Knowing that the light sensor had an issue, I assumed that the sound sensor would be similar and I added the same 200ms WAIT statement.

UPDATE: I discovered that this problem is an issue that currently exists in RobotC 2.0 and not with the SMUX and drivers.  I found that I was modifying the code, but new program was not being properly downloaded, thus the Light sensor was not getting the updated program to toggle the light on the sensor.  Xander has been gracious enough to work with me to identify the problem. 

RobotC has issued the following statement on the subject:
There is one primary known issue that we are working on, involving the "Compile and Download" command. The issue seems to be caused by ROBOTC incrementally downloading the program to the NXT and a memory issue on the PC-side where it is not recognizing changes in the program. We're close to a fix and an updated release - but in the mean time, try a suggested work around:

1. Open or modify your program inside of ROBOTC.
2. Save your program by going to "File - Save" (or use ctrl-S keyboard shortcut)
3. Go to "Robot - Compile Program" (or the F7 keyboard shortcut) - This step forces ROBOTC to regenerate the code from scratch.
4. Now go to "Robot - Compile and Download" (or the F5 keyboard shortcut) to download your program to the NXT.
5. Repeat these steps whenever you make modifications to your code.
HiTechnic has not released NXT-G blocks yet, and I look forward to seeing how they work. I hope it will give me even more insight that I can carry over to RobotC.

None of the legacy sensors are supported on the SMUX.  The HiTechnic IRLink is not supported because you cannot send commands though the SMUX, but that is not necessarily a bad thing since you still have three other ports available.

In an earlier post, I mentioned that there is an indicator light on the battery box. I was wrong. There are actually two indicator lights and they are actually on the SMUX. The green indicator shows that the battery box on/off switch is on and the red light shows that the NXT is turned on and connected. The SMUX will not operate unless both lights are on. Both lights turn off when the NXT is powered down. It’s actually a pretty handy feature.

Overall, I like the HiTechnic SMUX. I would recommend it, at least if you are a RobotC user.

NXT Base

If you are unlucky like me, your vision is going and the light in your computer area is dim. My computer station is in my basement and the lighting down here in the dungeon is just a couple of fluorescent lights. It makes reading the NXT screen difficult and results in having to hold the NXT up to see it clearly.

I have designed a standard base that I keep all my NXT bricks on all the time. It works great, it’s very stable, and allows easy access to all the ports. The NXT can be easily pulled off to change batteries. The best part is that it puts the NXT screen at an angle that makes the screen easy to read when working at the computer.

If you look at my Flexpicker, you will see that I used a similar mount to hold the bricks.

Lego Education 2010 New Releases.

TechnicBricks has a great article on some outstanding new releases coming in 2010 from Lego Education.  I highly recommend checking it out in case you have missed it.  Good stuff.

And while on the subject of Lego Education, their Clearance rack is full of great stuff right now.  CHEAP!

Saturday, December 5, 2009

HiTechnic Sensor Multiplexer Review Part 1

I just got the Sensor Multiplexer from HiTechnic the other day. I haven’t even plugged in a cord yet, but I wanted to share a few initial thoughts.

The first thing I noticed is that it is slightly bigger than I imagined. No big deal, I just imagined it to be a little smaller. It’s about 2 ¼ inches square and about 1 inch high or 7 studs square by 3 studs high. It is built to standard Lego dimensions so it will easily fit into your mounting.

HiTechnic carefully avoided infringing upon the Lego stud design my making all the protrusions and the distance between them one stud wide so a standard beam fits between them. You cannot snap the SMUX into your project so it must be captured between regular elements.

The second thing I noticed is that it has an external power source of a 9 volt battery box. There is a rather small red and black wire about six inches long connecting the battery box to the SMUX. I didn’t realize it required an external source because I was using the Touch SMUX as a reference which does not have the battery box requirement and I guess I didn’t look closely at the picture on the HiTechnic web site.

There is an indicator light on the battery box which has some functions related to the state of the SMUX and I will get into that more when I start to program it. There is a small on/off switch to turn the SMUX on during operation. You must use a small screwdriver to install the battery.

The battery box isn’t built to Lego dimensions, which makes mounting a little more cumbersome, but not overly difficult. The best way to mount is right now is probably using a couple of rubber bands and strapping it to other Lego elements. Personally, I wish that the battery box was incorporated into the SMUX. That way all the mounting could be done at the same time and I wouldn’t have to worry about breaking the small wires connecting the two during construction.

The distance between the ports on the SMUX are just wide enough for a beam to fit between them, but it is tight.

Wednesday, December 2, 2009

I am out of the office.

I won't be posting again until Saturday or Sunday, I am going to be out trying to get an awesome job I have lined up.

I did receive my HiTechnic Sensor Multiplexer today.  I haven't tried it yet, but I definitely have some comments I want to share about it.  I hope to do that this weekend.

Tuesday, December 1, 2009

More: Lego + Robot = Pretty Cool

Some video from the 2009 International Robot Exhibition in Japan.

Monday, November 30, 2009

Useful Lego

I found this pic on There, I Fixed It.  I thought it might make you smile.

Candle Making Kinetic Art

I considered building a robot that makes candles. This would be done by dipping the candle in different colored wax using some sort of overhead gantry to create a multicolored effect. Then using some sort of CNC lathe to create different diameters that would show off the different colors.

Then I get on YouTube, a natural source for learning and ideas. I didn’t find any real good “How To” videos, but I did find one interesting video. Someone actually turned the task of dipping candles into a sort of kinetic art.

Amazon Deal on NXT 2.0

Pretty good deal on NXT 2.0 from  $227.99 for the set.

Sunday, November 29, 2009

RobotC 2.0 Now Available.

After what seemed to be decades, the programmers of RobotC have announced they have finally released version 2.0. If you know anything about the program, it has been updated in the 1.xxxx realm many times and sometimes created more problems than were fixed. If you have paid the $30 for a previous version, the license is still valid and upgrading is free. If you want to try RobotC, you can download it and use a fully functional version for 30 days before you are required to pay the $30 license fee.

RobotC is my preferred programming environment when I need more power than can be found in NXT-G. I always recommend it, but the only real drawback I can say is that they don’t support Bluetooth communications between more than 2 NXTs. I am getting ready to download and install it, so I can’t really speak too much about the upgrade. In the past I have been pretty happy with updates, so moving up to 2.0 should be pretty easy and rewarding.

The upgrade can be done through this link.

From the RobotC website.

ROBOTC, a C-Based programming language for robotics
ROBOTC is the premiere language for educational robotics. It is a C Programming Language with an Easy-to-Use Development environment. It supports several different robotics platforms, including popular platforms such as the LEGO MINDSTORMS NXT and Innovation FIRST VEX. Download its blazing fast, High Performance Firmware to your robot. Using its Interactive Run-Time Debugger, you can easily pinpoint the problems in your programs. Try it out today by going to the Downloads section and choosing your platform.

Learnin' for Free

I found something incredible. The Ministry of Human Resource Development for the government of India has funded a program called The National Program Technology Enhanced Learning. It is an extensive program to help people get training in technology. I haven’t investigated the full reach of the program, but I have looked through the videos on and it is very impressive.

Incredibly, they have posted 4,251 videos. Most are one hour classes on different college level classes covering 117 different topics. Basically, it is a full college education on video free for everyone. All the videos are surprisingly in English, but the professors are Indian. Some are done very well, others not so much.

The list of topics looks just like a syllabus from any university. They include Electrical, Mechanical, and Civil Engineering, Mathematics, Physics, Computer Science, Electronics, and on and on. I have a couple that I am particularly interested in; Mechanical Robotics and Mechanical - Kinematics of Machines.

Here is the playlist for the entire program.  Very impressive.  To give you a taste, this is the video for Introduction to Robotics.

Friday, November 27, 2009

Thursday, November 26, 2009


This is a pretty cool robot. I have thought about building a bot that shoots, but haven’t really figured out a good way of locating the target. Shooting at a light source or something might work.

The best part is the builder gets shot at by his own creation.

Monday, November 23, 2009


Some years ago, I worked several times (mostly unsuccessfully) to build a pendulum clock. I had no problems with the hand movements, the gearing, the weights, the pendulum, the structure; I had it all figured out. But I had lots of problems working out the escapement. An escapement is a device which converts continuous rotational motion into an oscillating or back and forth motion. This creates the familiar tick tock sound.

Very generally speaking, the pendulum, the weight and the escapement work together to create the power of the clock. The weight pulls on a drum which turns the escapement wheel. The escapement wheel transfers very small impulses of force to the pendulum to keep it swinging. The pendulum will always swing at a constant pace or period, thus a pendulum is a great way to keep accurate time.

The tricky part is creating an escapement that will work regularly, have enough power to keep the pendulum swinging, and not too much so the pendulum is over powered and swings wildly. YouTube user BenVanDeWaal seems to have this problem licked. It seems he has devoted his entire Lego building existence to building escapements, and I might say he has done a very nice job.  He has several videos of several escapement types, but here are a few of my favs:



There are many more, and if you like these, go visit BenVanDeWaal's site.

Wednesday, November 18, 2009

Short Dry Spell On Posts

Sorry about the short dry spell on posts.  We are dealing with the flu bug all around us, plus I am preparing for an interview for a really great job.

But here is a neat video of some non-robotic kinetic sculptures.

Be back soon!

Friday, November 13, 2009

Friday's Idea-Omnibot

Omnibot was every boys dream in the mid 1980’s. If you had one, then you also had a complement of jealous friends, me included. Just another example of how 25 years takes away the feeling of “I have to have one” and replaces it with the feeling “I don’t want that junk, I have something much better.”

Building this out of Lego would be pretty cool, and the best part is that we could make it with many, many more functions.

Thursday, November 12, 2009

Mechanisms and Linkages

As I have mentioned over and over, I am a fascinated by motion and movement. I have posted a few kinetic art videos of which I am a huge fan, and there will be more. A few of my favorite classes in college were Kinematics, which is “the branch of classical mechanics that describes the motion of objects without consideration of the causes leading to the motion,” Dynamics, which is “the mathematical analysis of the motion of bodies as a result of impressed forces,” and the course that applies the two in real world applications, Kinematics and Dynamics of Machinery.

Much of the applied course was devoted to linkages and mechanisms. There are several classes of linkages and probably hundreds of named linkage arrangements. I own several books which verbally and mathematically describe many of the linkages. I get a kick out of looking at a machine and finding a linkage or mechanism that I recognize.

But I have a feeling that many of the linkages and mechanisms will be replaced by more mechanically simple servo motors and linear actuators. If you look at old machinery, you will find all kinds of cool movements generated by cams, levers, mechanisms and linkages, but with robotics and complex mathematics, some of those devices are obsolete. But they will never go away, and even more complicated linkages are being developed which I really like.

You can find tons of videos of many of linkages on and similar sites. One of my favorites is of course Theo Jansen’s Strandbeest.

The Strandbeest has been duplicated in several mediums including Lego. I’m not going to link to any of those videos out of respect for the artist, but some of those are quite impressive as well.  If you are not familiar with Jansen and the Strandbeest, I highly recommend visiting the link.

I have found several really interesting pages devoted to sharing linkage and mechanism designs and graphics. Here are a few;

RoyMech. This is a detailed page including all kinds of engineering resources, but my favorite is Mechanisms.

KMODDL. “KMODDL is a collection of mechanical models and related resources for teaching the principles of kinematics--the geometry of pure motion. The core of KMODDL is the Reuleaux Collection of Mechanisms and Machines, an important collection of 19th-century machine elements held by Cornell's Sibley School of Mechanical and Aerospace Engineering.”

Brock Institute for Advanced Studies. This page shows animated graphics for several linkages.

Kanagawa Prefecture’s Linkage mechanism simulator is a downloadable linkage simulator.

Tuesday, November 10, 2009

Roomba Pac-man

The Roomba is a robotic household vacuum cleaner. It’s a favorite hacking target of some people and you can find several blogs and videos around the net. Most of them are pretty lame compared to even a basic obstacle avoidance NXT robot. But this one is pretty cool and very complicated.

It would be way over my head to program, but nonetheless, fun to think about building with a full set of NXTs.

Sunday, November 8, 2009

Feel Good Lego Article

Completely not robotics or engineering related, just a great feel good story about Lego and family interactions.  I have a 4 year old who just points at the drawers for what she wants.

A Common Nomenclature for Lego Families

Saturday, November 7, 2009

HiTechnic Infrared Receiver

HiTechnic has posted a video demonstrating their new HiTechnic Infrared Receiver along with a Lego Power Functions Remote. They have built a pretty cool car with Ackerman steering that as demonstrated is pretty impressive.

The description reads as follows;
The HiTechnic IR RC Car features the new HiTechnic Infrared Receiver. This sensor makes it easy for you to control your creations using a LEGO Power Functions Remote.

This model is based on the LEGO Mindstorms 1.0 set. It also requires a LEGO differential and that is not part of the Mindstorms set. If you do not have a LEGO differential, you can go to and search for "Gear Differential", the part number is 6573.

Remote control - Using the HiTechnic Infrared Receiver and LEGO Power Functions Remote

Steering uses a PID controller Both NXT-G and NXC sample programs implement a PID controller to steer to a specified target position.

Ackerman steering - Which means that it has a steering geometry so that in a turn the inside front wheel turns sharper than the outside wheel.

Geared up to differential - Geared up 3:5. The drive motor has a 40 tooth gear driving the 24 tooth side of the differential.

Building instructions and sample programs can be downloaded from

Friday, November 6, 2009

Fridays Idea-Lego Music

Most of us have seen the video of the mildly cool Lego Band.

There have been a couple of computer generated versions that generated a little buzz.


But my favorite by far is one that was actually built. It was also done on very large scale apparently as an advertisement for Absolut Vodka. It’s a version that uses mostly flying balls, but also a little percussion and some wine glasses.

Obviously this would be an incredibly difficult build. One would have to not only know Lego robotics, but music and some physics as well. But I think it would extremely impressive.

Wednesday, November 4, 2009

Secret Knock Detecting Lock

If you haven't figured me out yet, I love to post projects that I think could made using the Lego NXT system.  I found one today that is pretty cool.  More inspiration.

I don't see many projects using the sound sensor, so this one is pretty special.  Just keep those batteries charged, or keep your key handy.

This is why I am not going to Robodays...

Look closely at 0:20.  Hollywood magic at it's worst.

Monday, November 2, 2009

Lego Lip Synching Robot

I just posted my latest creation. I take no credit for the idea, I posted a version earlier in my blog. It is programmed in RobotC and uses simply one sound sensor and one servo motor.

It was a fun build, and I think I will be able to use it in future projects.

Sunday, November 1, 2009

Talking Robot

Wow, I just saw this simple little project a guy built, and I thought it would be pretty simple to make with a NXT, a sound sensor and a motor. Set the motor to position the mouth open or closed based on the intensity of the sound. Pretty neat.

If anyone does this, I would love to show it off, so let me know.

Update: I have already built one of these. It turned out pretty well. Am working on a video now and I expect to have it in a day or two.

Friday, October 30, 2009

Friday's Idea

Here’s an idea that I think is pretty cool, a robot that lays bricks. Not Lego bricks, but regular construction bricks.

There have been a few artists and companies that have actually commercialized this and create wonderful works of art. Here is another link to a different company.

Make Magazine recently did an article on some of the mathematics that is required to make some really impressive textures on some walls.

I have tinkered with some of the math, and it is pretty detailed. I hope to get into this project in the future (get in line, buddy). If I do get into this project I would probably use something like dominos or home made wooden bricks to mimic the bricks and I think a gantry style robot will be much easier to construct and program.
I want to be Titan the Robot for Halloween.

Wednesday, October 28, 2009

Rapid Prototyping Using Lego

Hey! This is cheating! Not fair!

Lego in Mainstream Blogs.

Many don’t know that lots of techy blogs often post Lego related posts. What’s nice is they usually don’t post junk, so most of the posts are something that will interest most AFOLs. If you find a big blog that you like, you can usually find all the Lego posts by searching around in the tags. Tags are key words like Lego, Mindstorms, and NXT.

A few of my personal favorites (with links to Lego tags) are Make Magazine, Gizmodo, Boing Boing Gadgets, Wired Magazine, BotJunkie, Engadget, Singularity Hub and Robot Dreams. (Don't forget to come back!)

I would love to know if anyone else has found any good ones.

Tuesday, October 27, 2009

Early Factory Design Pictures

Here are some very early pics of the Factory so far..

This is the pallet. The pallet is pushed along the conveyor by a lug on the belt. The pallet actually slides on the smooth plates on the side.

The stop is used to position the front of the pallet. A device yet to be developed will push the pallet from the back into the stop. The conveyor will only get the pallet near the station. It will not put the pallet in the final location.
This is the downstream view of a cell. The grey bars on the side are where the pallet will rest. The pallet rides up on them as it enters the cell.
This view is the pallet beginning to ride up onto the cell.
This is a pallet with a very early version of the car sitting on top. The pallet is in position for assembly work by the robot to begin.

Keep in mind that all designs are completely open to redesign!!

Saturday, October 24, 2009

Robot sympathy

Halloween is great. Lots of horrifying animatronics come out and crazy robot costumes get shown off. Here is a video I enjoyed because for a moment I had sympathy for some wires, nuts and bolts and some wood. It's great because the builder personified the robot simply with eyes, teeth and some strange movements.

Somebody please do something to help!

Reality producer lands Lego

I have always wanted a show, a documentary, a series or something on TV about Lego. Looks like it is going to happen. has an article (Reality producer lands Lego) that states that there is something in the works

Five bucks says that Mindstorms won't get much air time. Just a hunch.

Friday, October 23, 2009

Fridays Idea

This is what I would build if I had 200 NXT sets and about 5000 hours of spare programming time.

Thursday, October 22, 2009

My Factory-The Plan

I wish I could say that I have as many bricks and Mindstorms parts as shown in the two videos below. I have far less, so I am going to have to be efficient in mimicking them. I have 4 NXTs, 2 RCXs, loads of sensors, and quite a few PF motors and accessories, lots of pneumatic stuff, and lots of 9V stuff. Every good project starts with a good plan.

Here are just a few ways I plan to be efficient;

1. I will build several cars at the same time.
I don’t want to be limited to building only one car at a time. I will have a continuous stream of cars going through the factory. At each cell, another piece will be added. All cells will work simultaneously and when all cells are complete, the process will cycle to the next car.

2. I will use a single stream to construct the vehicle.
On both of these video, you see grippers picking up assemblies and moving them to a different operation. I will be using a single long conveyor belt. Any construction to the vehicle will be done on that conveyor belt. This will force me to standardize, which will make constructing the whole factory easier.

3. All vehicles will be built on a pallet.
As the vehicle construction happens, each car will be placed on its own pallet or sled to move through the factory. This will mean that each cell will locate the pallet exactly the same way following a standardized system.

4. I will use a common pneumatic compressor.
I will build a large air compressor that powers all pneumatic actuators. This will have a standard pressure switch that will be used to turn the compressor on and off. The switch and motor do not use any control ports of the microprocessors.

5. I will excessively use PF motors and the HiTechnic IRLink.
Not all motions will need to have precise locations. I can use a PF motor much like a pneumatic cylinder. I will use a clutch gear and timing in the program to shift the motor from Point A to Point B.

6. I will use a single pneumatic interlocking pusher system.
In the videos, they show several locations where a motor is connected to a spur gear that drives a pusher down to interlock the Lego pieces. I will use a single air system that will push down at all cells at the same time after all parts are laid in place on all cells. This will use one motor to flip the switch.

7. I will use a single system to lock all pallets in place.
This will more than likely be a pneumatic system. As a pallet arrives at a cell, perfect alignment of all pallets at their cells would impossible. I will create a pneumatic system the will lightly push each pallet exactly into place and hold it while the robots work on the car. This will use one motor to flip the switch.

8. I will use a card system to input car details.
In the videos, the user chooses each car color by pushing a series of buttons. I will be creating some sort of card reader that will tell the factory which colors or details to place. This will use one motor and one sensor.

I think I have prepared a plan that will allow me to build a large factory with four to six cells. I have researched some automated car factories and my system mimics their facilities. I think what you will see if this plan works is an orchestra of moving parts. It’s going to take a pretty good conductor, and I hope I am up to the challenge.

Now the plan is in place, time to build. That’s fun part.

Tuesday, October 20, 2009

My Next Project is a Big One!

Well, the DominoBot is torn apart and I am thinking about my next project. I like big things, really big things, and I don’t mind spending months working on a project.

I haven’t posted in a few days because I have been thinking about tackling a project that I have wanted to do for a long, long time. Here are two videos that I have watched dozens of times.

Car Factory

Airplane Factory

These are great; they show lots of creativity and teamwork. It looks to me like an individual or small team constructed a station or cell and then all the cells are brought together to form one large construction.

I am going to give this a try. I think that both can be done with fewer processes and bricks, although I am truly impressed by the massive overbuilding of some components.

I am now trying to construct a vehicle that can be relatively easily mass produced. I am inventorying my wheels and other vehicle components. I don’t really want to purchase a bunch of parts that won’t be used in other projects, so I am trying to stick with what I have on hand.

Over the next few days, I will share some of the engineering choices I have made and why. I have put a lot of thought into this already, and I have some ideas that some of you may be interested in seeing.

By the way, this is a great team project and I am willing to work with others to expand!

Friday, October 16, 2009

The Lego Flexpicker

I realized today that I haven't linked to may current claim to fame, the Lego Flexpicker.

I had a great time with this build. I got tons of links from several big blogs and websites and was even invited to take it to an ABB Robotics show in Michigan. Check out this video and you will see the Lego robot at about 5:50

Mechanical Ecstasy

I became an Engineer because I have a great fondness for moving things. Lego allows me to quickly throw together ideas and realize thoughts in only a few moments. I easy get transfixed on complicated machines.

Then I found videos from superbird28 on This person is a mechanical God in my mind. Their creations absolutely mesmerize me. I will link to just one, but I strongly recommend that you check out all of this persons work. It is amazing.

Wednesday, October 14, 2009

DominoBot Video is now available

Thanks for checking it out!

Monday, October 12, 2009

Universal Joint Trivia

Look at the two shaft assemblies below. Identical, right? Not exactly.

Another name for a Lego universal joint is a Cardan joint. One of the drawbacks of a Cardan joint is that even when the input axle rotates at a constant velocity, the output shaft rotates at a variable speed. This can cause vibration in shafts that turn fast and inaccuracy in precision machinery. It’s not typically noticed with Lego because of several reasons. There is not a good way to very precisely measure rotational velocity and angle, there is torsion (twist) in the shafts and the gearing has a lot of backlash or slop, so we don’t see it or even care.

One way to partially overcome this error is to align the hinges on the universal joint as shown on Shaft A (90 degrees apart) and align the input and output shafts so that they are parallel. This is called a Double Cardan Shaft. This arrangement will result in an almost constant velocity in the output shaft.

Reference: Wikipedia
Wikipedia’s article on Universal Joints nicely shows the Equation of Motion for a universal joint along with a graph.

Sunday, October 11, 2009


Here are some pictures and information about the DominoBot.

DominoBot lays dominoes in a pattern to spell out a message. The basic premise is the same as a very very slow dot matix printer.

DominoBot uses one NXT, two servos to drive, one servo to open and close the gate, and eight medium PF motors controlled with the HiTechnic IRLink to push dominoes out of the magazine. The code is written in RobotC and the pattern and array are created in MS Excel.

Inspiration for this project, as I mentioned was Chalkbot. I considered several different mediums to spell out the message including spray paint, bricks, water and finger paint. I chose dominoes because I have two very large sets of dominoes (272 dominoes total), and it would be easy to pick up and reload.

The robot weighs over 25 lbs., so I had to carefully build the structure and drive train to be able to support that much weight. It will only work on level, flat surfaces. I once pulled it across the table and broke a gear, so when I move it I have to completely pick it up and place it, even very small distances.

DominoBot needed to be able steer and the wheels have to be extremely robust. I devised two pivoting trucks with four wheels each connected by a differential gear. The differential gear allowed a very wide base for each driving motor while still allowing it to turn.

The PF motors are used basically the same way a pneumatic cylinder would be used. I cycle the motors forward for 1.5 seconds to push out a domino and reverse for 1.5 seconds to retract the pusher. A clutch gear is used to “bottom out” the pusher on both movements, so a cycle actually takes less than 1.5 seconds.

The gate at the domino exit chute is an afterthought. I found that when the dominoes slide out, they tended to slide four to eight inches and made the message incomprehensible. The gate stops them at the bottom of the chute and releases them at the same time.

I used MS Excel to create the pattern. This worked great because I could size and fill in the cells to see exactly what the pattern would look like. Then I used a couple of Excel formulas and created the actual code that I could copy and paste over to my RobotC program.

Each magazine slot can hold 32 dominoes, which allows for about 10-12 characters to be created. The message programmed right now is “LEGO RULES.” Originally I made the magazine so that it would be filled from the top, then I figured out that it would be much easier to fill from the back.