5V MCU in 12V system

Discussion in 'Embedded Systems and Microcontrollers' started by rambohenke, Aug 28, 2014.

  1. rambohenke

    Thread Starter New Member

    Aug 28, 2014
    1
    0
    Hi!

    Iv'e gotten my hands on an old broken cnc router.
    I'm trying to switch out the old controller and work on a tight budget.
    There are 2 problems atm.
    TL;DR; versions.

    The buttons have internal lightning that requires 12V to light up.
    The lightning and switch has a common ground and one pin each.
    I'm not sure how to interface the buttons with a 5V MCU?
    Especially without risking of burning some component.
    Functions wanted, be able to control the light and sense the switch via the MCU


    I want to build a PSU that generates a regulated/switched 5V linear output.
    I'd rather it would stepdown the 12V from the PSU in the machine thats just been changed.
    Whats easiest/cheapest, to buy a 12V->5V psu or to build one?

    To make it a little more challenging it's supposed to be able to take cranks from the input, Meassuered to about 10-16V when starting and stopping the motors. And still deliver a stable linear output, just to make sure the MCU doesn't go bananas.
     
  2. shteii01

    AAC Fanatic!

    Feb 19, 2010
    3,377
    494
    Use computer psu. They have 12 volts and 5 volts already.
     
  3. shteii01

    AAC Fanatic!

    Feb 19, 2010
    3,377
    494
    Are the lights led?

    They might light up with 5 volts.
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,500
    2,365
    What CNC router and what/who's is the controller?
    Max.
     
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