Pro mini



  • Hi guys.
    I recently discovered mysensors and arduino.
    Im still waiting for stuff to build my gateway but today i recieved my first pro mini bought on ebay
    This is in the mysensors store.
    In the description on ebay it say 3.3V
    On the back on the board it say
    *8Mhz
    *16Mhz
    *20mhZ
    *3V3
    *5V
    in a comment on ebay someone say "3.3 or 5v flexibility"
    Can i feed this with 5v on the VCC?



  • Hello and welcome @xydix,

    the back of the board is to mark the actual model you have, it is often not marked by the factory.
    The description clearly says that it is the 3.3V 8Mhz Version.
    The VCC pin is to directly feed the microcontroller and should be regulated to 3.3V.
    The RAW pin runs into the oboard voltage regulator and can be feed 3.3V - 12V (Be aware that most china clones don't withstand the full 12V)



  • @Oitzu
    Thanks for the quick reply.
    Nice to got that sorted out.
    Thank you.


  • Contest Winner

    @Oitzu said:

    The RAW pin runs into the oboard voltage regulator and can be feed 3.3V - 12V (Be aware that most china clones don't withstand the full 12V)

    Do not forgot about stabilizer dropout. I saw three variants on pro mini boards:

    1. LDO (low dropout) stabilizer like LM1117/AMS1117 - dropout is about 0.9-1V, so you can feed 4.4-18V. I think it is the most popular variant.
    2. Ordinary stabilizer like 78L03/78L05 - dropout is about 1.6-2V, so you can feed 5-18V. Be careful - these boards are popular.
    3. Ultra LDO stabiliizer like XC6202 - drouput is about 0.25mV, so you can feed 3.5-6V (!maximum voltage is limited).
      :smirk:


  • But if i want to save battery, shall i cut the regulator on the pro mini even if i am planning to feed it with 3v (2 AA) to VCC?
    Or is it better with a 9V to the RAW and keep the onboard regulator?


  • Contest Winner

    @xydix
    Of course remove LDO :wink:



  • This post is deleted!


  • @Oitzu said:

    The RAW pin runs into the oboard voltage regulator and can be feed 3.3V - 12V (Be aware that most china clones don't withstand the full 12V)

    I can attest to this fact, since in the last few weeks I fried 3 clones building my 12v led controller before realizing they just can't handle 12v on the raw/vcc pin.


  • Admin

    @micah I have had this happen to a couple of mine too. It only takes a few times before I learned never to apply 12v to the raw pin :grimacing:
    I have been able to revive all of my pro minis by soldering on a new capacitor here:
    0_1478302519907_upload-0e34ea93-e569-4bda-a128-01f155ebb85e


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