Game Idea

I was sitting around tonight thinking about the really cool game that is showcased on http://www.nxtprograms.com/.  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.

UPDATE:
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..

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.

Cool Coasters

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

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

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.

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

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!

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.

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.

More: Lego + Robot = Pretty Cool

Some video from the 2009 International Robot Exhibition in Japan.

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 Amazon.com.  $227.99 for the set.