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Bring on the Heat: Thermal Imaging with the NXT

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Lookin' Hot!I built a pan and tilt rig for the Dexter Industries Thermal IR Sensor with a great deal of gearing down to allow me to take a lot of measurements as the rig moved around. Initially I had it set for about 40×40 measurements but those didn’t look that great and I wanted a bit more. I reprogrammed it and made it spit out data at a resolution of about 90×80.

The data from the thermal sensor was streamed to the debug output console in ROBOTC from which I copy and pasted it to an Excel worksheet.  I made some 3D graphs from the thermal data and it looked pretty cool.

Excel graph for cold glass Excel graph for candle flame

The left one is a cold glass and the right one is a candle.  I wasn’t really happy with the results of the graphs so I decided to quickly whip up a .Net app to read my CSV data and make some more traditional thermal images.  A few hours later, the results really did look very cool.

Thermal image for cold glass Thermal image for candle flame

Again, the left one is the cold glass and the right one is the candle.  Now that you have a thermal image, you can see the heat from the candle a lot more clearly. I made a quick video of the whole rig so you can get an idea.

A few days after the initial post about my thermal imaging system using the Thermal Infrared Sensor, I made some improvements with both the speed and accuracy of the whole thing. I made the sensor sampling interval time based, rather than encoder value based. This proved to be a lot better at getting consistent sampling rates. I also doubled the horizontal motor speed so I would be more likely to be still awake by the time it was done taking an image.

The left image was made with the old system, the right one with the new system. It’s a lot less fuzzy and there are no black gaps where the number of samples were fewer than the maximum number of samples in a row.

image_thumb7 image_thumb8

Perhaps there are other ways to improve the program but I am quite happy with how this has turned out.

The driver and program will be part of the next Driver Suite version. You can download a preliminary driver and this program from here: [LINK].  The .Net program and CSV files can be downloaded here: [LINK]. You will need Visual Studio to compile it.  You can download a free (Express) version of C# from the Microsoft website.

Written by Xander Soldaat

June 16th, 2011 at 4:47 pm

Dexter Industries dGPS Sensor with Google Maps and ROBOTC

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Ever wanted to plot your path on a roadtrip or walk through the woods? Wanted to see where your robots went while you were asleep?

Dexter Industries has just made it super easy to do this and even more with ROBOTC using their dGPS sensor for the LEGO Mindstorms NXT!

The dGPS Sensor is $105.00 and is available from Dexter Industries.
Note: ROBOTC users can save 10% by typing in “robotcdgps” (without quotes)  in the coupon code area at checkout and receive 10% off the price of the dGPS until March 1st, 2011!

Using ROBOTC, the NXT and the dGPS sensor, you can download the included sample program program, drag it all over the earth, and then snap! open the file in Google Earth and see where you went.  In five easy steps:

  1. Download and send the sample program to your NXT.
  2. Attach the dGPS sensor to sensor port #1 and wait until it gets a signal.
  3. Start the program and proceed to wander around.
  4. Stop roaming. Connect your NXT back to your computer and using the NXT’s File Management dialog  (Robot – NXT Brick – File Management), download the file “Path.txt” to your desktop.
  5. Rename the file to “Path.kml”.  Double click the file to open with Google Earth and…  Voila.

Here’s a short video produced by the guys over at Dexter Industries showing off the cool new technology:

Written by Tim Friez

January 4th, 2011 at 4:51 pm