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

    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
    Use computer psu. They have 12 volts and 5 volts already.
  3. shteii01

    AAC Fanatic!

    Feb 19, 2010
    Are the lights led?

    They might light up with 5 volts.
  4. MaxHeadRoom


    Jul 18, 2013
    What CNC router and what/who's is the controller?