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433 Mhz RF Nexa. Transmitter and receiver with Arduino.

Arduino projects to send and receive RF signals at 433 Mhz. Decodes the same protocol that uses the Nexa.

Arduino A
Velleman TX433N
velleman RX433N
You can also use 433MHz RF transmitter and receiver link kit mä of which is cheaper.

Control a Nexa PB-3.

Code to read the remote control from Nexa:
(AM-HRR3 receiver test)

To send to Nexa-breaker:

Adding the code goes here if the other links fail:

Posted in Arduino
28 Comments »433 Mhz RF Nexa. Transmitter and receiver with Arduino.
  1. JSP007 says:

    Hej Sebastian,
    I did download your files (excellent that you post them here!) and it works fine über controlling NEXA.
    First, one must of course find out the codes that apply to their own remote control with receiver file, change the line and then everything works, ie it clicks wonderfully in NEXA receiver in the slot.

    However, I had done wrong the first time. Thought I would load the Control Easy-library first but then I could not even compile. Nay, Just click on your homeeasyhacking.ino and everything gets going!

    Fun, tack!

  2. HULK says:

    Fail to compile homeeasyhacking.ino example. Has zipped up and put it as a folder in libraries.
    Some tipps on what you are doing wrong?

  3. Jonas Franklin says:


    Snyggt! Jag har försökt få till detta men lyckas inte med kopplingen. Har du möjlightvid ett kopplingsschema eller ett foto på din installation?


  4. Simon says:

    If you do not have a receiver to read the codes so you can send the code 0 - when the lights / turn off everything. Even neighbors nexa receiver.

  5. Patrick says:

    Interesting, but I think it is a shame that they put so much work but then explain how to use it. Here there is not even a proper description of what the code is good for.
    I can Arduino, programming and electronics and would like to control the Nexaenheter with an Arduino, and I think this blog post shows how to do. But there is no information!

    • Sebastian Nilsson says:

      The code can be used to read and send nexa commands. The code and the video explains how to use it. But I can agree that the documentation is not in top class.

  6. Robert Nilsson says:

    Howdy, thanks for an interesting video. I hold myself to get to a similar solution that ultimately govern heater to the car based on temperature and lighting switches (all based on NEXA). But I have never used Arduino before and would like to have some info on how you connected the stuff on your breadboard. I have the following equipment:
    Arduino Uno Rev3
    Velleman TX433N and RX433N

    According to the documentation in rf_receiver and Homeeasyhacking you should use a pin 8 input and pin 13 för output. So I have attached the following but have no input in serial console when I press the remote-NEXA:

    Recipients > Arduino
    Pin 1 > GND
    Pin 2 > Pin 8
    Pin 3 > no
    Pin 4 > 5 V
    Pin 5 > 5 V
    Pin 6 > GND
    Pin 7 > GND
    Pin 8 > ANT

    Transmitter > Arduino
    Pin 1 > GND
    Pin 2 > Pin 13
    Pin 3 > 5 V
    Pin 4 > ANT

    I've opened. Ino files you attached on our website in the Arduino SDK:n and since these uploadat to Arduinon. Arduinon flashes when I press the upload as serial port seems Meeting (running MAC so this is the name / dev/tty.usbmodem471).

    Any tips you can give is welcome.



  7. Erlend says:

    Beginner Question: Now I get the receiver to flash on and off, as in the original sketch. But what is a simple on command, and what is a simple on command?

    (I want to use Nexa-thing in a thermostat of the type
    if(temperature>=17.00) { //turn on Nexa }
    if(temperature<=17.00) { //turn Nexa }

  8. Oskar says:

    Hi I have all the equipment and it works but I would like to write tex a h1 so illuminates a particular lamp and l1 so turns off the lamp, How should I write it in my code? Thanks also for the very inspiration!

  9. Karl says:

    you need an aerial for the transmitter? and what is the link to the arduinon out?

    • sebnil says:

      No but one antenna makes sending and receiving better. The connection to the Arduino is not documented but it should be relatively simple to read out from the Arduino code.

  10. Daniel Åkesson says:

    Har provat med två olika mottagare, en från ebay samt en från kjell som var identisk med den du använde. Använde ditt arduino exempel och får det att fungera med de båda men räckvidden är urusel, funkar stabilt kring 10cm och ostabilt upp till 1m.

    Har monterat antenner och provat lite olika längder, 17cm samt 30-35cm men hjälpte inte. Några tankar? Har gjort experimenten med arduino UNO inkopplad på USB-ström.

    • sebnil says:

      Test the external power source that is more powerful. Some usb charging current is weak. Otherwise, it is difficult. I put their antennas on both receiver and transmitter. Keep in mind that the length should match the frequency on the one you want to send (433 Mhz). It can also be another device that interferes with out.
      Good luck!

      • Daniel Åkesson says:

        Great Tips, but no luck sorry :S Tried with an external power supply at 12V 1A but it didn't still lower at ~ 5 cm.

        Use the nexa transmitter in the apartment with telldus etc. and there are no problems otherwise with the transmitters/receivers and the scope is sufficient throughout the apartment.

  11. Henry says:

    It was not right to work directly. A problem seems to be scope. Right now, the remote control must be within 10 centimeters from mottagararen but I'll test with an antenna. 17 cm stripped-down kulo-cable is a tip I found.

    Then I adjust the timing a bit. I use the values from this sketch:

    Used a Nexa remote control

  12. Gustav says:

    Thanks for the great example!

    Have a little problem though. I've got a Telldus Tellstick as remote but I am unable to read the code it sends to my Nexa switch. What I wonder is if you used the Nexa self-learning system? Understand that the self-learning system using a trust different protocol. To the code in the homeeasyhacking function of self-learningsystemet?

    Or maybe a real Nexa remote control would solve the problem.

    Tacksam för svar 🙂

  13. sebnil says:

    Unfortunately, the answer is that I don't know. I have not tested against self-learning.

  14. Frederick Hjärpe says:


    Interesting project which I was going to try me on. My thoughts are:
    1 - I've been using the Arduino Mega instead of buying the expensive Telstick Net but it,
    most thought to use it as a timer?!

    2 - Räckviddsproblemen, it has to do with the distance between the Arduino - remote control
    or Arduino - Nexamottagarna?

    3 - I've been meaning to have 16 St. nexa recipients but is there any limit on the number of?

    I have two Arduino Mega card and it is ideal for this purpose, it takes care of itself after the programming, which neither Tellstick Duo or Tellstick, do not depend on enn computer is on 24/7 If you want timer!

    Mvh Fredrik

  15. sebnil says:

    1. Yes.
    2. Has to do with bad antennas. May also impact and that the application code is not optimized.
    3. No practical limit what I know.

    Good luck!

  16. Frederick Hjärpe says:


    What I've seen, it is easiest to use a: Breadboard for putting all the components on or build any kind of box!

    In the hardware path do I need only:
    1 - Arduino cards
    2 -
    3 -
    4 - An antenna, the longer the better?
    5 - Something to build everything into!
    6 - Koden du har lagt upp 🙂
    7 - Tålamod 🙂

    It is not so expensive with 150:-, already have the arduino cards and wires, etc..

    Mvh Fredrik

    • sebnil says:

      All right except 4an. The antenna is made to match a rate which in this case is 433 MHz. I think it gives a length of approx. 17 cm but I can remember errors.

  17. cecilia says:

    I wrote a tutorial about this one. You might be able to find some details there.

    • Mattias says:


      Jag får inte min nexa-fjärrkontroll (den som ingår i setet NEYC-3, 3 strömbrytare och enkel fjärr). Du skriver i rf_receiver.ino att man eventuellt behöver "relaxing the timers". Kan du utveckla hur man bör gå tillväga för att ringa in signalen? Jag använder förresten XD-RF-5V köpt via ali med 17cm antenn, funkar kanon med andra kinaprylar på 433mhz så som brandvarnare och kontrollers.

      • sebnil says:

        Kan tyvärr inte hjälpa till. Har inte hållit på med nexa på ett bra tag så jag är inte riktigt up-to-date längre. Men lägg gärna en kommentar om du får det att fungera. Det finns säkerligen andra som är intresserade.

        Lycka till!

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