10 replies to this topic

[CopMike]

Hi all!

I´m really really new to this so I will show my ignorance here in public ! I need to have my NXT to perform these easy tasks:
* Have a Power Functions motor to turn a number of 360´s - stop for a while - and then turn back to starting position.
* Work as a switch for getting light-emitting diodes turned on/off - two different set of LED´s at different times.
How do I go about it?

Thanks in advance / Mindstorms Rookie Copmike

[JopieK]

Arduino might be easier and cheaper, but.

Using some convertor cables you could attach PF to NXT. A PF motor is not a servo, so you need to compute what 360 degrees is.

For the LEDs: http://www.tau.ac.il.../lego/i2c-8574/

[DLuders]

@ CopMike:  Have you seen Artifex Creations' Brick Lights?

P.S.  Thanks for donating all of the wonderful Unimog parts for the TSATS contest winners!  

[Blakbird]

CopMike, on 11 April 2012 - 10:01 AM, said:

I´m really really new to this so I will show my ignorance here in public ! I need to have my NXT to perform these easy tasks:
* Have a Power Functions motor to turn a number of 360´s - stop for a while - and then turn back to starting position.
* Work as a switch for getting light-emitting diodes turned on/off - two different set of LED´s at different times.
How do I go about it?

Power functions motors don't have any position feedback, so there is no way to know for sure how many times they have turned. You'd have to program the NXT to just run for a certain number of seconds, but no matter how careful you are it would off after a few cycles and would not return to starting position. With a NXT motor you can command a specific number of degrees of rotation so what you are suggesting would be easy.

As long as you can convert the LEDs to plug into a NXT connector through a converter cable, turning them on and off at whatever time you like should be pretty easy. You could probably just program them as motors and tell them to go to 100%.

[CopMike]

Thanks for the input guys - I really appriciate it ! Now I just need to understand it also !

* Which NXT motor should I get instead of the PF one?
This one- 53787
or this one 9842

* I´ll need to read through your supplied link again (and again) JopieK to get it, but I also wonder what I need to program it. So far I only have a black NXT !

Again I apoligize for the rookie questions!

[legolijntje]

I would go for the 53787, because that are the most recent ones from the nxt 2.0 set.

Edited by legolijntje, 11 April 2012 - 08:19 PM.

[DLuders]

9842@ CopMike:  There is no difference between the two NXT motors you found, just as there is no difference between these Power Functions motors:

58121c01 and 8882 are both "Power Functions XL Motors".  Bricklink lists both numbers, although Shop.Lego.com only lists the 8882.



58120c01 and 8883 are both "Power Functions M-Motors".  Bricklink lists both numbers, although Shop.Lego.com only lists the 8883.



You can get the 53787 "Electric, Motor - NXT" or the  9842 "Interactive Servo Motor" -- they're the same!      Shop.Lego.com sells the 9842.

      

Edited by DLuders, 12 April 2012 - 12:10 AM.

[Blakbird]

CopMike, on 11 April 2012 - 08:13 PM, said:

* Which NXT motor should I get instead of the PF one?
This one- 53787
or this one 9842

The motors are the same so just get whichever is easier for you to find. They will have a wire that plugs directly into the NXT and is capable of tracking number of revolutions.

Quote

* I´ll need to read through your supplied link again (and again) JopieK to get it, but I also wonder what I need to program it. So far I only have a black NXT !

The color of the NXT doesn't matter either. They are both the same, just a different color. In fact, the black is much more rare and collectible!

To program it you need the NXT Software with comes with the NXT. If you don't have the software, you'll have to buy it on Bricklink or try to get a replacement from LEGO customer service..

To connect your lights you will need this adapter cable.

I am by no means a NXT expert. In fact, I only bought the NXT, built the first model, and then sold it. Even so, I'm pretty sure I know how to program what you are trying to do. My point here is that the language is really easy and all you need to do is follow the instructions for one or more of the sample models and you'll know what to do.

[DLuders]

@ CopMike:  If you don't have the Lego Mindstorms NXT software, you can download the Lego CD-ROM images on this Brickfactory webpage.  The zip files will have the same files as the original CD-ROMs.  

  

Edited by DLuders, 12 April 2012 - 01:22 AM.

[Steamrunner]

Probably safest to download the software direct from Lego themeselves: http://service.lego....questionID=2655

This is also the best way if you're a Mac user; the disc that came with the NXT 2 doesn't install on Lion, but the version you can download from the Lego site does.

[CopMike]

Thanks everyone for the useful information ! Motors and stuff ordered, and program downloaded.
I´ll be back with updates (and maybe for sure more stupid questions) !