I2C Interfacing Part 2: Analog-to-Digital, Pressure Sensing, and 5V Power
Saturday, December 30th, 2006
A pressure sensor allows you to stop a motor that operates a Lego pneumatic compressor when the pressure is high enough to actuate pneumatic cylinders and to start it when the pressure is too low. This prototype sensor uses an analog pressure sensor chip to measure pressure. The analog measurement is converted to a digital value and sent to the NXT using an I2C analog-to-digital converter chip. A slight complication is caused by the pressure sensor, which needs a 5V power supply. But thanks to I2C, the sensor is still very simple.
The full details are available here.
Posted in hardware, hacking | 3 Comments »
Omni Teaches Physics
Wednesday, December 27th, 2006
Ever since I saw Steve Hassenplug’s “Omni” (see also in NXTLOG), I wanted to make one of my own. Last week, I finally obtained enough wheels via Bricklink to make the three “omni-wheels” needed. Working on Omni, I soon realized that controlling the three motors is actually the toughest problem with this type of robotic motion. If you want Omni to move in any one direction, you should (in general) operate all three motors in varying speeds. The videos showing Omni in action suggest that Steve controlled each motor independently using a second NXT sending BT commands to the Omni NXT brick. I wanted to use my PSP-Nx PS2 Controller Block and maneuver Omni with a wireless PS2 controller. In this post, I’ll describe how this is done and how Omni can be used to teach students something on elementary rigid body kinematics.
Posted in personal, video, projects, news | 45 Comments »
Hi-Technic Color Sensor on Shop@Home
Tuesday, December 26th, 2006
The holidays bring the NXT community a nice little gift on the LEGO Shop@Home site - the Hi-Technic Color Sensor.
See a rainbow of color!
Using the NXT Brick (sold separately), the Color Sensor enables your robot to distinguish not only between black and white, but also a range of bright and pastel colors.
Does not include connector cable.
This is the individual component, and does not include the NXT Intelligent Brick, software or any accessories. It requires the complete LEGO® MINDSTORMS® NXT set (#8527) for use.
Posted in hardware, news | 3 Comments »
Mindsensors Infrared Distance Sensor
Tuesday, December 26th, 2006
Coming soon from mindsensors.com - a high precision infrared distance sensor. Available end of January.
Introducing series of high prevision infrared distance sensors using I2C bus digital interface. These sensors will provide reading directly in millimeters.
These sensors will have built-in calibrations to provide high resolution readings. When not in use, the sensor can be powerd down to conserve battery.
The sensors will come in ranges as follows -
Short range sensor: 4cm to 30cm
Medium range sensor: 10cm to 80cm
Long range sensor: 20cm to 150cmScheduled to be available by end of Jan 2007.
Posted in hardware, news | 2 Comments »
PSP-Nx Block example
Tuesday, December 26th, 2006
I was asked for a simple PSP-Nx sample program. Since this may be of common interest, I post it here. As you can see from the image the program is trivial, controlling motor B and C using the two joysticks Y axis. You can download the .rbt file here.
Posted in projects, news, software | 52 Comments »
NBC/NXC new beta
Thursday, December 21st, 2006Beta 15 of NBC was released yesterday morning for Linux, Mac OSX, and Win32 platforms. In this beta there are literally hundreds of new NBC API macros (~250) defined in NXTDefs.h. Wrapper macros for all the drawing system functions are now available (PointOut, RectOut, LineOut, CircleOut, GraphicOut) as well as IOMap-based wrapper macros for drawing directly to normal and popup screen memory.
Also available are several macros which allow direct access to the High Speed input and output buffers, the USB input, output, and poll buffers, the Low Speed input and output buffers, and the Bluetooth input and output buffers. New macros have been added which provide full access to the 30 element Bluetooth Device Table as well as the 4 element Bluetooth Connection table and Brick Data information.
New NBC opcodes have been added to the compiler (strindex, strreplace, strlen, shl, and shr). There is new support for compile-time checking of variable sizes (via sizeof and compchk operations).
NXC has a number of new API functions, including several for string variable manipulation (with support for strings of any size). The new string functions in b15 are NumToStr(value), StrCat(str1, str2, …, strN), SubStr(str, idx, len), StrReplace(str, idx, newStr), StrToNum(str), StrLen(str), and StrIndex(str, idx).
http://bricxcc.sourceforge.net/nbc/
BricxCC has also been updated to support the expanded NXC and NBC APIs. The latest test release is available from the main BricxCC page in the NXT News section.
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LEGO plays hidden camera with the NXT
Monday, December 18th, 2006LEGO has put out two marketing videos (Robot Power and Robot Attack) where they placed 2 NXT robot demos and a hidden camera to record people’s reactions… Have a look for a good laugh….
Direct Link: http://5×5m.com/files/mindstorms/
Posted in general, video, news | 1 Comment »
Feed Me! Feed Me! Feed Me!
Sunday, December 17th, 2006
What can I say? This hungry little fellow is a very picky eater. He is very hungry. If you don’t feed him often, he demands food. But when you feed him, he says that the food is disgusting and spits it out.
If you are looking for a compact robot with a strong personality, then you have found your match.
More details and a video are available.
Posted in news | 4 Comments »
DynaTrax - What to do with those Cool Technic snowmobile tracks
Saturday, December 16th, 2006Sometimes my robot building ideas are spurred by nothing more than wanting to make use of one or more cool items that I get from time-to-time. In this case it’s two - tread tracks that can be had if you own the Technic Snowmobile (8272) and a TechnoStuff Tilt/Accel Sensor. I was fortunate to have received a huge bag (a few hundred segments along with cog wheels) of the new tread tracks a while back and begun playing with them to see how they compare to their smaller black Technic counterparts.
I like these ones better as they are larger (more suited to the size of robots and Technic creations I build) and stronger - they dont come apart as easy. They also have pin holes in them to boot, so the sky is the limit if you want to expand the width of the tracks using pins and beams, or technic plates. Imagine the possibilities!
So, what do you do with a load of these tracks? Build a robot that uses almost all of them - DynaTrax. This bot is not so much practical as it is just cool (at least I think it is….). I also thought it would be cool to make the tread carriers dynamically expand and contract and shift the tread length with a 3rd remote channel. You can also use the tilt sensor to detect slope and dynamically change the tread length to suite… Find out more and watch a video at www.astolfo.com.
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