Issues between Wifi (router) and NRF24L01



  • Hi guys,
    I have an Arduino gateway very close to the wifi router (about 10 cm). The Arduino has a NRF24L01 PA LN (amplified) version. This antenna is feeded via the Raspberry 2 (that acts as controller of Domoticz).
    So, I don't think power is a trouble (clean energy from Raspberry, not using that poor USB cable). Energy taken from the 5V and using the socket for the antennas that step down the voltage to 3.3:

    alt text

    The antenna is the version from Aliexpress (CDEByte: https://it.aliexpress.com/item/E01-ML01DP5-Ebyte-2-4GHz-20dBm-2100m-nRF24L01-SPI-Wireless-transceiver-module/32638720689.html?spm=a2g0s.9042311.0.0.dT6b9h ) But I also did try the "standard black" version.

    On a node far about 5 meters, I have the same amplified antenna (it's a barebone atmega, antenna is powered from a 2A 5V supply powered down to 3.3V with LD1117T (so, clean energy to the amplified version).

    On the amplified version I did not use any capacitors.

    My issues are when a PC wifi connected download very big files and Wifi is stressed. The nodes lost theyr parent.

    If wifi is no used / light load, no issues.

    I have same issues if I use normal version (not amplified) with 4.7uF caps on the VCC and GND.

    I did try also move the wifi channel to #12, without any advantage.

    So, I would ask you:

    1. What channel do you hint for wifi OR NRF?

    2. I'm trying to search a good sketch to test the NRFs between 2 simple Arduino, to measure trip, delay and test with different capacitors and / or with different shield. Can you hint me some sketch?

    Thank you very much


  • Hero Member

    @sineverba The first thing to try would be to move your gateway further from the router. Even if they are on different channels being only 10cm away could be too close.

    If that is not possible then there are still things to try. Your Idea of a test node to sort the range issues is a good start. If you have a look at this post you can see the one I used for my initial testing, it has been very helpful in deciding where to locate my repeater nodes as well.

    I ended up running my network on a different channel to avoid crowded channels and reduce the risk of a possible clash with another MySensors network. To see what is happening on the 2.4GHz around you you could build the simple scanner shown in this post .

    Experimenting with the capacitor on the nrf is also a good idea. On my recent Aux battery node I found I had to go to a 100uF before the node became stable. Don't be afraid to throw a few .1uF ceramics into the mix as well just to see if that helps, you will see them used a lot on Vcc lines etc.

    On the unshielded NRF24L01+ PA LN devices it was found to be beneficial to wrap them in foil to stop feedback entering the circuit. Yours is shielded but again it doesn't hurt to try. There was a post on the method, can't find it at the moment though. I think they named it the ugly fix.

    Try a non amplified nrf as well.


  • Mod

    My nrf24 gateway is about 1 meter from my router but I am running on channel with frequency as far as possible from my wifi network. Also I'm using nrf24 adapter from gearbest that has built in caps and it is working perfectly.


  • Mod

    @gohan Same here:

    0_1510397010821_20171110_221154.jpg

    Netgear is the router, white box my MySensors nRF24 gateway.
    No issues whatsoever ;-)


  • Hardware Contributor

    I have a Wifi router, NRF Ethernet GW, a DHT22 NRf24 node, RFM69 GW and RFLink (yea, both 433mhz) all cramped in together within 60cm without issues in any freq.



  • Thank you to all for your efforts. I will try the @Boots33 methods and sketches, moving by @gohan method further away the NRFs channel from the wifi.
    Unfortunately I cannot move the PI (and gateway) far from the router, but I am very sure that the issues are for the wifi, when it is under heavy load.
    I know also that breadboard jumper are not the best cables to connect these antennas (waiting for custom pcb to remove them...) and they can create other issues.
    This is, btw, my current placing:

    alt text

    So, I hope that moving the channels will give me max stability.
    I will update the post with next tests.
    Have a nice day!

    OT: @Yveaux I want that box! Is it available from some place??? What is there inside? Arduino?


  • Mod

    I am going with the Pi hat that has both nrf24 and rfm69 on it


  • Mod

    @sineverba said in Issues between Wifi (router) and NRF24L01:

    OT: @Yveaux I want that box! Is it available from some place??? What is there inside? Arduino?

    It's just a generic project box I had on stock. Bit large, as it contains an uno, ethernet shield and proto board with nrf24 and some leds.


  • MySensors Evangelist

    @Yveaux Nice enclosure ;-) I don't dare to show my box. Always interested in visuals of the inside of this stock box of yours. Just for some old Chinese copy paste work ;-)



  • It seems that moving to last channel all nodes and gateways solved my trouble.

    In this moment wifi is under heavy load (upload several video from several phones and tablet) and traffic leds never light the infamous red... neither nodes lost their gateway :) :)


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