I’ve been lucky enough to have had the pleasure of trying out the new Firgelli Linear Actuator (LA) for a little while now and it’s awesome.  It’s based on one of their pre-existing LAs and is completely NXT compatible.  It connects to the standard NXT motor port like a regular motor and has encoders, too.  The LA comes in two sizes, 100mm and 50mm and extend at an unloaded speed of about 12mm per second. 

The thing that struck me the most is the accuracy of it.  With 200 encoder ticks over the entire length of the LA for the 100mm version, you can position the end point with a 0.5mm accuracy.  You’ll have a hard time trying to duplicate that level of accuracy with the regular motors. 

I took some pictures of the 100mm version next to some studded beams so you can get an idea of how big it is in its retracted and extended positions.  You can click on the images for a larger version.

There is an easy to use NXT-G block available on the website that has built-in stall detection to protect the LA.  Danny Benedettelli has written an NXC library for it and you can expect a driver to be included in the next release of the 3rd Party ROBOTC Driver Suite.

For more technical details, have a look at the datasheet which you can find here: [LINK].

I’ll be posting a video of my little test robot in the next few days on my blog, so keep an eye out for that.

We recently picked up one of those Aquasaurs kits for the kids – which lets you hatch and care for some neat little aquatic fish (or shrimp) that date back to pre-historic times. After reading the instructions we got everything set-up and all was good, until we read the part about the temp of the water needing to remain between 72 – 80F. Problem is, we tend to keep our house around 70ish, and during the day, we have our automatic thermostat drop the temp to more frigid temps (to conserve you know!). We quickly realized that these things would likely not get past the larvae stage at those temps. For the first two days, we had the tank propped up on the stove under the halogen lights to keep the water warm. However, over time, they would heat the water too much and need to be monitored / turned off for periods of time.  We needed to come up with a longer term solution.

One option would be to simply go out and drop $$ (insert cost here – I don’t know) on a aquarium heater – but that would be too easy.  I’d rather take my $300+ extra NXT & temperature sensor and make them work for a bit. Now you ask yourself, how the heck would the NXT heat the water.  Well, that’s where dSwitch from Dexter Industries comes in. Interestingly enough, the dSwitch did not come to me with the intent of using it to heat the Aquasaurs tank. It was more like irony and good timing that I just received the dSwitch and we got the Aquasaurs going.

For a full description and pictures, visit my site at www.plastibots.com.

Hey folks,

It’s been a while since I last made a bot.  My latest is DualGrip - NXTRover (or DG for short).  I wont go into great detail as all info (with videos) can be found at my site http://www.plastibots.com, but DG has both tracks and wheels and uses an acceleration sensor to determine when it is climbing and deploys the
drive system to angle itself to engage the rubber wheels.

The NXT 2.0 retail set comes with a new color sensor.  It is an analog sensor rather than I2C like the HiTechnic color sensors.  The LEGO color sensor requires the firmware that comes with the retail NXT 2.0 set (version 1.28).  The firmware that comes with the recently released NXT 2.0 education software (version 1.26) does not include support for the LEGO color sensor.

NXC and BricxCC now support the new color sensor in the pre-release (aka test release) build that you can download via the following URLs:

http://bricxcc.sourceforge.net/test_release.zip

http://bricxcc.sourceforge.net/nbc/beta/nbc-1.0.1.b36.tgz

http://bricxcc.sourceforge.net/nbc/beta/nbc-1.0.1.b36.osx.tgz

Read the rest of this entry »

It’s hard to program when you’re dosed down with cold medicine and you keep coughing over and over again until you’re not only sick you’re sick of coughing.  That’s me right now, unfortunately.  Fortunately, I’ve been able to string together enough coherent thoughts and coordinate my fingers sufficiently to upload another update to the not-yet-officially released b36 version of NXC.

Read the rest of this entry »

Several people have posted questions on the nxtasy forums asking for help connecting to their NXT via Bluetooth using the Bricx Command Center (BricxCC).   

First, make sure you have the latest test release of BricxCC.  You can always download it from this link:

http://bricxcc.sourceforge.net/test_release.zip 

Extract the zip over your existing BricxCC installation. 

Read the rest of this entry »

I have uploaded a new test release of BricxCC and NBC/NXC tonight (11/30/09 at 9:00pm CST).

http://bricxcc.sourceforge.net/test_release.zip

The biggest change is support for enums.  At the moment NXC does not enforce types on enums so you can define a variable of an enum named type and then assign to that variable any integer value rather than only enumerations that are a member of the named enum type.

http://bricxcc.svn.sourceforge.net/viewvc/bricxcc/tests/enums.nxc?revision=264

Read the rest of this entry »

National Instruments has just released the

LabVIEW Education Edition,

http://digital.ni.com/worldwide/bwcontent.nsf/web/all/D281AF3F29196D83862576470065AE02

the best stuff I’ve ever worked with in the context of LEGO robotics. The features are so fantastic that we have succeeded with few efforts in implementing a Kalman filter to our infrared/ultrasonic indoor GPS system for the 2D-positioning. The very first tests are very rudimentary, but all this is extremely promising.

Note also that the latest 3D sound localization robot also has been programmed with the brand-new software.

http://www.convict.lu/Jeunes/RoboticsIntro.htm

Hey everyone,

 As you probably have noticed, the forums were down for the last few days.  From what I can gather the ISP hosting nxtasy.org, aplus.net, has recently been sold to a new owner.  As part of the sale, sites hosted on a shared server are all being “upgraded” to a new datacenter in Florida.  There are messages from many disgruntled aplus.net customers who have experienced numerous problems as a result of this move.

http://forum.aplus.net/showthread.php?t=481

“Aplus.net is currently upgrading customers to an enhanced hosting platform which will allow you to take advantage of a variety of new services over the coming months. The upgrade is over halfway complete and has been successful overall.”

“As with any platform change there have been a few bumps along the road though. If you are experiencing account problems during this process, we would like to apologize for any inconvenience this may have caused you.”

“We recognize that many of you use this forum to express your frustrations. However, due to privacy concerns we will no longer address account issues on the Aplus.net forum. If you need additional account assistance, please email escalations.support@cs.aplus.net and a member of the Aplus.net escalations team will follow up with you.”

I began a series of strongly-worded emails with the above email address on Monday.  Yesterday evening I finally received a response.

“Good evening, I’m the Escalation Manager for Aplus.net and will be taking over your issue from support to make sure we have our migration team take a look into this tomorrow.  Since it’s the holiday we will email you updates unless your request otherwise.  Our teams will be working tomorrow so we’ll get you an update throughout the day as soon as we have it.”

As of Thursday, 11/26/2009, at 6pm CST the forums are back up and running again. Hopefully aplus.net will get their act together and avoid breaking them again as they continue their “upgrade” process.

John Hansen

I am sure I am not the only one who has run out of sensor ports before on their NXT.  Well now you need not worry about that problem anymore.  HiTechnic brought out their long-awaited Sensor MUX today.  It’s not just a port splitter but it also takes care of polling the sensors for you, so it will work with I2C and analogue sensors.  You can have up to 4 of these SMUXs connected to your NXT in all.  The following sensors are currently supported:

• Analogue (EOPD, light sensor, gyroscope, sound sensor)
• Lego Ultra Sonic Sensor
• HiTechnic Compass Sensor
• HiTechnic Colour Sensor, both the new and the old one
• HiTechnic Accelerometer Sensor
• HiTechnic IR Seeker Sensor, both the new and the old one

I’ve had the pleasure of owning one of these beauties for a few months now, so I could work on a ROBOTC driver for them.  I will be releasing a new version of my suite later today, so keep an eye out on the project page.

HiTechnic have come out with a new sensor today.  This time it’s a sensor that will allow you to control your brick with one of the PF remotes.  The  IRReceiver can be used with both the PF IR Remote Control and the newer PF Speed Remote Control.

It would allow you to use your PF remotes to control your NXT motors in a very precise way.  How about a robot that won’t run into a wall, even if you accidentally steer it towards one?  I’ll be building mine into the holonomic drive robot I’m currently working on to allow manual control for demoing purposes.  I can’t wait to get my hands on it!

There have been a number of reports that a fresh install of the LEGO MINDSTORMS NXT software on Snow Leopard (Mac OS 10.6) fails.  From LEGO support comes the following instructions for a work around:

“Copy all files from the Mindstorms CD to a folder on your desktop. Open that folder and look under “Parts”. Locate MindstormsUnivEdu.pkg or MindstormsUnivRet.pkg. Right-click and choose “Show Package Contents”. Navigate into the Contents/Resources directory and delete the “preflight” file. Close this package and run the meta-package from the [folder on your] desktop to install Mindstorms NXT.”

If you use a Mac to program your NXT then do yourself a favor and check out the new build of my NeXT Tools application for Mac OS X. In this application you now have at your disposal the tool windows from the Bricx Command Center (BricxCC) IDE that have historically only been available for Windows PCs.

This native carbon application gives you Mac versions of the direct controller tool, diagnostic info, watching the brick, the brick piano, the brick joystick, the remote tool, messaging, memory map, MIDI conversion, Wav to RSO conversion, firmware download, and the NeXT Explorer and NeXT Screen tools. It supports communication via both USB and Bluetooth. And it’s a universal binary that runs on Tiger as well as on Leopard or the recently released Snow Leopard OS.

Download the application from the utilities page on the BricxCC site.

Here’s a message from Ralph Hempel, developer of pbLua:

I’m pleased to announce the release of pbLua Beta 18a. Yes, I’m still calling it Beta, but the feature set is pretty much frozen and I’m just fixing bugs as they come up. I expect to do a non-Beta release Real Soon Now…

The main pbLua site is now easily found here

You can download the latest zip file with firmware and sample code here

There are tutorials here

Here is a summary of the new stuff - and I think I’ve got the last of the really ugly bits cleaned off…

1. Reduced image size (134.5K) - more room for file and log storage (121.5K)

2. Support for the NXT 2.0 color sensor

3. Generally improved sensor handling - just specify the type, no need to fiddle with the direction and value of the digital I/O

4. Preprocess sensor values in raw, pct full scale, edge, pulse and other modes. Support (untested) for RCX angle sensor

5. Support for the synchronise mode on motors

6. Selectively load portions of the NXT library to save RAM space

Have fun, and please feel free to email me with any questions.

Ralph