πŸ’¬ Easy/Newbie PCB for MySensors



  • Dear All!

    I would like to use this PCB. I would like power it with 5V, but I would like to use a 3.3V version mini Pro. How should I do it? I would like to use it from 5V (USB adapter) or battery 2xAA . Could I do it?

    Best regards,
    T


  • Mod

    just power it from the usb adapter, the pro mini can work at 5V. If you have other HW not 5V tolerant you need to use the RAW pin and let the pro mini regulator to its job. It all depends on what you want to do with the node



  • Dear @gohan !

    Thank for your help!
    Which configuratation should i use? Or do i have to modify one of the above configurations? (3.3V , 5V regulated, or 6-12V) ?


  • Mod

    There is no right answer since without knowing what you want to do, they could be all wrong or even all correct. :)


  • Hardware Contributor

    @Tommas 5v + 3.3v pro mini there is no example for this. Add your 3.3v pro mini and radio. Connect 5v to raw and put a jumper/connect both reg and bat.

    If you want to use to for 2xaa please follow the example.



  • @sundberg84 I do have the same problem with my setup. As soon as power drops below 2.8 the radio will have problem connecting to gateway. Sometimes it connect after 10-15 tryes. Is there any way to see if nrf sending or any outer way to test stuff? Any ideas are welcome //HΓ₯kan


  • Hardware Contributor

    @keldandorin - are you using a booster as mentioned above?
    The problem is in that case noice introduces in the radio from the booster (a known issue). I will in the future try to buy me a oscilloscope and diagnose more... but for now, if you add a "bad/cheap" booster it will be this problem. 2.8v sounds really bad though, and most likley a really bad clone.

    You have two options.

    1. Try another booster, and/or try to filter with capacitors.
    2. Load a new bootloader that can handle lower voltages accoring to link above.

    Let me know if I can assist you in any way.



  • Dear @sundberg84 !
    Thank you! ANd which example should i follow with this modification?
    Thanks
    T



  • @gohan

    Dear gohan!
    I would like to power all my nodes from a central power source with 5V . I would like to use 3.3V microcontroller with 3V sensors... because of the voltage drop down caused by the distance (5-15m from the power source). Maybe there will be 1-2 battery powered sensor nodes..
    This is my plan.
    I dont like using battery. It is too hard for me to optimize the sensors for battery...

    Best regards
    T


  • Mod

    In that case you could also go for rs485 bus. Voltage sources could be also 7 or 9v since you will be using the internal regulator anyway. Most sensor can operate at 5v too, so you don't actually need 3.3v. Optimizing for battery isn't that bad too. Since you are powering the nodes you could also use esp8266 nodes



  • Dear @sundberg84

    If i use 5V regulated example, has it got 3.3V output for the sensors?

    Thanks
    T


  • Mod

    if you install the voltage regulator in the top left area, you will have the 3.3v ( if I got your question right)



  • @gohan

    Oh OK! Thank you! The decision is hard for me, which solution i should use:) .



  • @Tommas If you are using 5 volts in and not using a 3.3v pro mini that has the 3.3v regulated output, then you have to add a TO92 case style 3.3v regulator and two capacitors to the board. Here are some that should work. Whatever one you get, make sure you check the pinout against the markings on the board as not all regulators have the same pinout.
    http://www.mouser.com/Semiconductors/Power-Management-ICs/LDO-Voltage-Regulators/_/N-5cgac?P=1z0y3jsZ1z0wa2e&pop=88zz




  • Hardware Contributor

    @Tommas - this is the voltage regulator that the board is designed for so the markings/pinout will be right for you. If you put 5v on the PCB input and use 3.3v pro mini though, the only choise you have is to put 5v on RAW and let the onboard voltage regulator on the PCB regulate it down to 3.3v. The voltage regulator on the PCB only regulate the voltage to the radio and are meant for a 5v input on a 5v pro mini. Using raw means there is no need for the LE33.



  • @sundberg84 Is there any way to say if booster is a bad one or not before ordering them?
    The one I ordered was the one on shoping list from aliexpress. Will try I capacitator and see if I can get a new booster from kjell&Comany tomorrow just to try. Build a setup on bread bord where I powered radio with 2 AA and got the same result. Got a fju places where I like to put some sensors with no power so realy need to get this working :). Could the radiomodules be bad to?


  • Mod

    Bad quality from cheap Chinese suppliers, is always an option 😁


  • Hardware Contributor

    @keldandorin - could be a weak clone radio yes.
    Just to get your hopes up, I got booster driven nodes all around the place with Nrf24l01+ radio and they works great!
    I change battery every 1-1.5 years but as I said, the experience is that the radio - booster needs a good teamwork :)



  • @sundberg84 Sounds good, Thats what I'm looking for. Have never worked with tinkers like this befor so everything is new. But this place is great thx for taking time.



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