Electromagnetic field from step-up regulator interferes with NRF24

  • I am experiencing issues with the NRF24 radio module when powering the Pro Mini off a step-up regulator, stepping up from two 1.5 volts batteries to 3.3 volts. When I connect the Pro Mini to an FTDI programmer everything works as normal.

    A while ago I read that regulators created an electromagnetic field that could cause interference with the radio module. My tests seems to confirm this.

    Is there some way I could eliminate , limit or somehow "enclose" the electromagnetic field generated by the regulator?

  • Hardware Contributor

    I am not sure if the fields are what actually interferes with your NRF24. The module is just very dependent on a clear power source. Step up regulators often generate much noise though. Adding some caps might help though. There are also some tips about building some kind of low pass filter to prevent this somewhere in the forum.
    I would just try to remove the voltage regulator and run the pro mini of of the 2 batteries though. Both mini and NRF work down to 1.8V (with the right fuses).

    If its really the electromagnetic fields some ground plane or a metal enclosure might help as far as I know.

  • Mod

    You can run the nrf24 radio directly from batteries and use step up for arduino

  • Thanks to both of you @LastSamurai and @gohan, that seems to solve alot of issues regarding the noise.

    However I experience some strange values when connecting Arduino directly to the battery. The power to the LED not 0 volts (as it is when powering Arduino and radio from FTDI programmer), but 2.8 volts. And around 3 volts when pressing the doorbell button. I can't quite figure out why it acts like this. Not only that, but the digital pin connected to the anode side of the LED gives power to the Arduino itself.. Even when I disconnect VCC/Ground on the Arduino from the batteries, the Arduino gets power through the digital pin. I didn't even know that was possible.

    Not sure what doorbell type it is, but it's a cheap one bought at my local supermarket.

  • Mod

    I advise you to make a fritzing diagram so we can understand how you connected everything, otherwise it is quite hard.

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