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Can I tap into an existing 5v to power my own project?

Discussion in 'General Electronics Discussion' started by dippnerd, Apr 11, 2018.

  1. dippnerd

    dippnerd

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    Apr 11, 2018
    Hello! I'm working on a project to make my "dumb" AC smarter by using a NodeMCU to transmit IR codes remotely. I'd love to hide the NodeMCU inside of the AC to keep things tidy, and realized there's a 5v and Ground easily accessible. This got me thinking, why not tap into that 5v and power the NodeMCU without needing a second power supply? I'm curious if there are any reasons this might be a bad idea. The 5v is to power the control panel for buttons, LEDs etc. The only problem I was thinking is if the AC compressor causes a power surge, but it seems to handle that part for the panel, but is there anything else to be concerned about? Thanks in advance!
     
  2. kellys_eye

    kellys_eye

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    Jun 25, 2010
    Depends on the power rating of the supply and how much extra you intend to draw from it.

    If your circuit doesn't cause the existing power supply to overload then there's no reason why you can't use it.
     
    dippnerd and Cannonball like this.
  3. dippnerd

    dippnerd

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    Apr 11, 2018
    I haven't done any tests yet, but it sounds like it's not terribly power hungry, and all I'm doing with it is lighting up an IR LED on occasion (though it does have wifi which i can see being power hungry). I'm going to do some tests but wanted to make sure I wasn't forgetting anything obvious, I haven't done this kinda stuff in a while :)

    Thanks!
     
  4. kellys_eye

    kellys_eye

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    Jun 25, 2010
    I shouldn't think an additional 20mA (LED) would do any harm. No PSU I know of is THAT power critical!
     
    dippnerd and Cannonball like this.
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