what do you think about my first simple circuit?

Discussion in 'General Electronics Chat' started by cmrincon, Apr 14, 2018.

  1. cmrincon

    Thread Starter New Member

    Oct 25, 2017
    26
    1
    Hi!

    I'm a electronics student who is making a garage door opener. Im using a pre-made ask transmiter module with 50 ohm matching network, and a pic12f675. As power source im using a 12V LR23 battery and a LDO regulator. It has 2 buttons and only it is useful for 1 door..but with more free time i will add a receiver ask module and make a programmable garage door oppener.

    I'm worried about leaving vcc pin of the TX module in open circuit...IO1 is at low level ALWAYS that IO3 is at high level. What do you think about this? will i have any problems?

    If everything is ok i will start making the pcb tonight. Thanks


    Regards.
    Cesar
     
  2. cmrincon

    Thread Starter New Member

    Oct 25, 2017
    26
    1
    i noticed one error. U1 has 4 pads, there are 2 missing in the schematic! 1 of them goes to ground and the other one to 12V
     
  3. kubeek

    Expert

    Sep 20, 2005
    5,292
    995
    don´t forget some way to program that pic, and maybe an oscillator if it needs it.
     
  4. AlbertHall

    AAC Fanatic!

    Jun 4, 2014
    6,648
    1,556
    The battery life may not be too good. Even if the PIC is sleeping the battery will still be supplying power to the supply regulator.
     
  5. DickCappels

    Moderator

    Aug 21, 2008
    5,003
    1,518
    Leaving the transmitter VCC open should not be a problem, but AlbertHall it might be best to keep the transmitter VCC connected to the output of the regulator and switch power to the regulator. You can get 3.3 volt regulators that draw only a few microamps quiescent current if the regulator's current is a concern.


    Microchip MCP1702-3302E/TO Low IQ Regulators <== pdf datasheet
     
    ebeowulf17 likes this.
  6. cmrincon

    Thread Starter New Member

    Oct 25, 2017
    26
    1
    Hi!

    Thanks you all! ;)

    My idea was avoid using switches. About the regulator..i liked the MCP1702 LDO regulator, it's a great idea!

    About the current consumption, i didn't notice that big mistake about the power regulator!
    Finally im thinking about using a switch like DickCappels suggested, probably is the best solution.
     
  7. takao21203

    AAC Fanatic!

    Apr 28, 2012
    3,783
    502
    its quite wasteful to drop from 12 to 3.3v with such a small battery.
    Have you thought to use a CR2032 or LI-Ion?
     
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