Lego and DAQ

[Jolanta]

SEarl: I am gonna try and build Lego X-Y table now such that it holds my laser sensor which is scanning the object and moves it in X-Y direction. I am still not sure about how to acquire three co-ordinates of an object???

[ESearl]

You can read the encoders of the of the lego motors using the same sensor node you were using to read the color sensor-- Just configure it to read rotation.

[Jolanta]

OK the rotation sensor gives me angle of rotation motor does, depending upon the rotation. So now I have the data from my encoder and my laser sensor. So I have the angle and height. So I need one more co-ordinate??

Thanks

Jolanta

[ESearl]

I'm assuming you will be using two motors to move your sensor around, one motor for the x coordinate, and one for the y. You will need to read both angles independently.

[Jolanta]

yes i m using two motors independently. But I m not sure of how to get x,y,z co-ordinates of the object scanned by laser.

So the story is: Laser sensor is scanning any object and Lego X-Y table is holding and moving the sensor. Now Laser gives output in the form of voltage and two motors will give me the rotational angle values. Now the concern is how to convert these three values and get a X,Y, Z co-ordinates of object in the form of graph? These 3 co-ordinates will be used to get the 3D shape of an object.

The bigger picture is to use laser and lego to get 3D shapes of an object. 

[ESearl]

Hey Jolanta,

I imagine you can just scale the rotation value to get a linear value. The scaling factor will depend on the specifics of the linkage from the motors to the xy table. Just turn the motor until its encoder reads 1000 and then measure the distance the sensor moves . The quotient of distance/1000 will be the scaling factor.

[Jolanta]

Hi sorry I am a baby to LabView but what does it mean by "The scaling factor will depend on the specifics of the linkage from the motors to the xy table."

I suppose I should first build the X-Y table to hold and move the Laser, get voltage and 2 rotational angular values of the motors and then think about the later part of converting these values into linear x,y,z co-ordinates.

But just frank question. Do you think I will be able to get x,y ,z co-ordinates of an object after scanning by this laser and lego X-Y table?

[ESearl]

Sorry, I assumed you had already built the table. What you are describing sounds possible to me though. Good luck!

[Jolanta]

Ok I will get back very soon.

Thanks for your help and suggestions.

[Jolanta]

Dear benjamin

You were nice to introduce me to NXT toolkit.

Now I will try and build the XY-table to hold and move my laser sensor.  As I will have the angular rotation values and voltage from laser I will get back to you if thats ok?

Thanks again

Jolanta