Relay or something else?

Discussion in 'General Electronics Chat' started by xeuse51, Nov 4, 2013.

  1. xeuse51

    Thread Starter New Member

    Nov 4, 2013
    Hey everyone,

    I have a question regarding what I need to use in the following layout. I am brand new to circuitry in my Engineering 100 class, so this is coming from a total noob.

    Our project is to build an autonomous hovercraft using a NXT controller to do line following. Here is the issue. I don't know what I need to use to have the NXT to switch on power on from the 12v batteries we are using. The NXT signal will be used to tell our steering fans to be on or off. The 9v from the NXT is not enough power to push our fans to operate at max capacity, so we have some 12v's for that. What type of control switch can I use when the NXT sends the signal for a fan to be on or off, but have the fan use the 12v batteries? I hope I have worded this problem in the correct fashion and I am sure there is another forum with an answer for this. Any help would be much appreciated.
  2. crutschow


    Mar 14, 2008
    If the NXT signal and the 12V batteries have a common ground then you should be able to use a power MOSFET to switch the fan power.
  3. MikeML

    AAC Fanatic!

    Oct 2, 2009
    Do you have a link to the NXT controller? I am assuming that it is some kind of ucontroller project board. If so, it most likely only puts out 5V; not 9?

    Transistors, bipolar NPN/PNP or MOSFETs NFET/PFET are most commonly used to switch motor loads on/off.
  4. tubeguy

    Well-Known Member

    Nov 3, 2012
    What is the current required for each fan?
  5. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    Google "NXT relay driver"
  6. adamclark


    Oct 4, 2013
    a 5 pin automotive relay could easily do what you need,,, but the mosfet is probably a better idea because you can just figure it into your circuit,, but the relay would take 5 minutes to wire in and could easily be removed for testing or other things...