Sending data from Arduino to Raspberry Pi via NRF24L01+

  • I am trying to send some ultrasonic data from an arduino uno to RPI3.
    My Arduino Code is:

    // Enable debug prints to serial monitor
    #define MY_DEBUG
    // Enable and select radio type attached
    #define MY_RADIO_NRF24
    // Set LOW transmit power level as default, if you have an amplified NRF-module and
    // power your radio separately with a good regulator you can turn up PA level.
    #define MY_RF24_PA_LEVEL RF24_PA_LOW
    // Enable serial gateway
    // Define a lower baud rate for Arduino's running on 8 MHz (Arduino Pro Mini 3.3V & SenseBender)
    #if F_CPU == 8000000L
    #define MY_BAUD_RATE 38400
    // Enable inclusion mode
    // Enable Inclusion mode button on gateway
    // Inverses behavior of inclusion button (if using external pullup)
    // Set inclusion mode duration (in seconds)
    #define PARK_OFF_TIMEOUT 20000 // Number of milliseconds until turning off light when parked.
    #include <MySensors.h>
    #define SEND_STATUS_TO_CONTROLLER  // Put a comment on this line for standalone mode
    //#include <NewPing.h>
    // Enable debug prints to serial monitor
    #define MY_DEBUG 
    #include <SPI.h>
    #include <MySensors.h>
    #define CHILD_ID 1
    MyMessage msg(CHILD_ID,V_TRIPPED);
    unsigned long sendInterval = 5000;  // Send park status at maximum every 5 second.
    unsigned long lastSend;
    int oldParkedStatus=-1;
    #define echo_Pin 6 // Echo Pin
    #define trig_Pin 5 // Trigger Pin
    int blueledPin = 3;      // the pin the LED is attached to (use one capable of PWM)
    int greenledPin = 7;
    int redledPin = 2;
    int a = 850;
    long duration, value;
    void setup() {
      // initialize serial communication:
      Serial.println("Starting distance sensor");
      pinMode(greenledPin, OUTPUT);
      pinMode(redledPin, OUTPUT);
    void presentation()
      sendSketchInfo("Parking Sensor", "1.0");
      present(CHILD_ID, S_DOOR, "Parking Status");
    void loop() {
      //and the distance result in centimeters:
      pinMode(trig_Pin, OUTPUT);
      digitalWrite(trig_Pin, LOW);  // Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
      digitalWrite(trig_Pin, HIGH); // The sensor is triggered by a HIGH pulse of 10 or more microseconds.
      digitalWrite(trig_Pin, LOW);
      // Read the signal from the sensor: a HIGH pulse whose duration is the time (in microseconds) 
      // from the sending of the ping to the reception of its echo off of an object.
      pinMode(echo_Pin, INPUT);
      duration = pulseIn(echo_Pin, HIGH);
     // value = microsecondsToCentimeters(duration);  // convert the time into a distance
     value = (duration/58.138);
      Serial.print ("cm");
      Serial.println(); // Displays readings one beneath other.
      delay(500); // Rate of displaying the readings
       // Update parked status
        int parked = value != 0 && value < 54;
          if (parked)
            { Serial.println("Car Parked");
              digitalWrite (redledPin, HIGH);
              digitalWrite (redledPin, LOW);
            { Serial.println("Car Gone");
              digitalWrite(greenledPin, HIGH);
              digitalWrite(greenledPin, LOW);
            #ifdef SEND_STATUS_TO_CONTROLLER
            oldParkedStatus = parked;
            //lastSend = now;

    While this code runs succefully (I Hope)

    I would like to send the collected data on to a wordpress site from the Raspberry Pi 3 (RP3 is hosting one already). I would prefer to send it to an OpenHab or a controller to implement some functions.

    But the main issue I am facing is this error.0_1484644214264_Screen Shot 2017-01-17 at 1.04.16 PM.png

    The configure used is 0_1484644245687_Screen Shot 2017-01-17 at 1.04.53 PM.png

    Some help would be appreciated.

  • Mod

    Are you trying to use the arduino with the SerialGateway sketch to send data over NRF24 to the Rpi3, or do you have 2 arduino boards connected over NRF24 and one of them is the serial gateway connected to the Rpi3?

  • @gohan
    Using Arduino with Serial Gateway sketch using NRF24L01+ to a Rpi3

  • Mod

    The serial gateway is supposed to be connected via USB and it is sending data over the usb serial port, so for your project you would need an extra Arduino as a sensor node where you will connect the 2 sensors (look at the MySensors library examples) with a NRF24 module that will be sending data to the other Arduino with the other NRF24 configured as serial gateway and connected to the RPI3 via USB. MySensors library allows you to setup your gateway also as Ethernet (with a W5100 shield) or Ethernet with MQTT client (also need the W5100 shield).
    If you want to add a controller, consider starting with Domoticz as it is very easy to connect to whatever gateway mode you chose.

  • @gohan

    So what gateway would be chosen if the data is sent from the Arduino to the rpi3 using these modules?
    I mean I saw a youtube tutorial to send it directly from an arduino to the rpi3 and I figured the same would be possible using a my sensors library and instruction.

    I don't wish to add an Arduino to the rpi3 just for data collection.
    Any suggestions?

  • Mod

    No idea actually. So far I have only made experiments on these libraries. If I were you I'd spend 6-7$ for an additional Arduino and save you a lot of time.

  • @mfalkvidd

    Any solution?

  • Mod

    @LaMB95 I am not sure I understand what you are trying to do but maybe you can use on the rpi3 and remove the gateway part from your Uno.

  • Mod


    If I understood correctly he is trying to send data directly from an arduino in the garage, that is checking if car is parked, over nrf24 to a raspberry, but of course the serial gateway sketch is not gonna work.

  • Mod

  • Mod

    @gohan better to use which is compatible with MySensors 2.

  • @mfalkvidd @gohan

    What I am trying to do is to put the arduino in my garage and send this data to something like OpenHab or Wordpress such that I can see the parking status from another location.

    And a couple of youtube tutorials I saw were able to send the data from an arduino to a pi (without any USB cable) using this radio.
    I was hoping such a method is possible using the MySensors library.

    Another question I have is what aout using a virtual serial port ? But I think I would need an ethernet shield on the arduino. Am I right?

  • Mod

    @LaMB95 I don't know about virtual serial ports but sensing data from one Arduino to a gateway (which can be a raspberry pi) is exactly what MySensors is about. describes how MySensors works. I suggest you start there, especially the part labelled "The sensor network"

    In MySensors terminology, the arduino in the garage will be a sensor and the raspberry pi will be a gateway.

  • @mfalkvidd

    I checked the page!
    It was quite helpful and I realise that a serial gateway is not something that I need.

    I need some help to understand the working of a virtual serial port.

  • Mod

    As a beginner as I am, I'd go with 2 Arduino boards and use one as gateway; it really simplify the initial setup even if you you actually have more hw. Meanwhile you could study how to use the nrf24 on the rpi3, that's more complicated and if you are not experienced it is easier to make mistakes

  • @gohan

    Well considering how difficult it seems at times I think I will stick to it for now.

    Could you point me towards the tutorial you used for your project?
    I might try to create something for the time being with your help!

    Thanks !

  • Mod

    For the serial gateway just read , it's quite straight forward as you just need to use the code in the example in the library and choose your customization options in the #DEFINE at the beginning of the code (DEBUG, type of radio, power level, if you want the 3 monitoring blinking leds); things get a little more complicated for the sensor nodes if you want to have more sensors attached to a single node, because you need to copy multiple code from examples and try to blend everything together; but if you start with a simple sensor node and tinker a little with it, then you can add more and more complexity looking for ideas around the forum or just google around.
    To me the most difficult part has been getting the radio working because I bought some crappy modules that I had then replaced with working ones and that cost me a lot of time because I was afraid I was doing mistakes but I actually did everything correctly (as soon as I plugged in the new modules it started to work).
    After I got communication established I just configured in domoticz a new hardware and I could choose either serial/Ethernet/mqtt mysensors gateway and that was it. As soon as you add new sensors that present themselves you can find them as "unused" sensors in the controller; after that it's all up to you. If you don't like the controller just install a new one and connect the gateway to it and you are ready to go.

  • @gohan

    SO what changes did you make to the gateway arduino in order to recieve the data from a sensor node?

  • Mod

    Here is the code of my ethernet gateway, so for serial just ignore all the part about network and w5100

    // Enable debug prints to serial monitor
    #define MY_DEBUG
    // Enable and select radio type attached
    #define MY_RADIO_NRF24
    //#define MY_RADIO_RFM69
    #define MY_RF24_PA_LEVEL RF24_PA_MAX
    // Enable gateway ethernet module type
    #define MY_GATEWAY_W5100
    // W5100 Ethernet module SPI enable (optional if using a shield/module that manages SPI_EN signal)
    //#define MY_W5100_SPI_EN 4
    // Enable Soft SPI for NRF radio (note different radio wiring is required)
    // The W5100 ethernet module seems to have a hard time co-operate with
    // radio on the same spi bus.
    #if !defined(MY_W5100_SPI_EN) && !defined(ARDUINO_ARCH_SAMD)
    #define MY_SOFTSPI
    #define MY_SOFT_SPI_SCK_PIN 14
    #define MY_SOFT_SPI_MISO_PIN 16
    #define MY_SOFT_SPI_MOSI_PIN 15
    // When W5100 is connected we have to move CE/CSN pins for NRF radio
    #ifndef MY_RF24_CE_PIN
    #define MY_RF24_CE_PIN 5
    #ifndef MY_RF24_CS_PIN
    #define MY_RF24_CS_PIN 6
    // Enable to UDP
    //#define MY_USE_UDP
    //#define MY_IP_ADDRESS 192,168,178,66   // If this is disabled, DHCP is used to retrieve address
    // Renewal period if using DHCP
    #define MY_IP_RENEWAL_INTERVAL 60000
    // The port to keep open on node server mode / or port to contact in client mode
    #define MY_PORT 5003
    // Controller ip address. Enables client mode (default is "server" mode).
    // Also enable this if MY_USE_UDP is used and you want sensor data sent somewhere.
    //#define MY_CONTROLLER_IP_ADDRESS 192, 168, 178, 254
    // The MAC address can be anything you want but should be unique on your network.
    // Newer boards have a MAC address printed on the underside of the PCB, which you can (optionally) use.
    // Note that most of the Ardunio examples use  "DEAD BEEF FEED" for the MAC address.
    // #define MY_MAC_ADDRESS 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED
    // Enable inclusion mode
    // Enable Inclusion mode button on gateway
    // Set inclusion mode duration (in seconds)
    // Digital pin used for inclusion mode button
    // Set blinking period
    // Flash leds on rx/tx/err
    // Uncomment to override default HW configurations
    #define MY_DEFAULT_ERR_LED_PIN 1  // Error led pin
    #define MY_DEFAULT_RX_LED_PIN  2  // Receive led pin
    #define MY_DEFAULT_TX_LED_PIN  3  // Transmit led pin
    #if defined(MY_USE_UDP)
    #include <EthernetUdp.h>
    #include <Ethernet.h>
    #include <MySensors.h>
    void setup()
    void loop()

    In MyConfig.h i changed these so it applies to all nodes/gateways

    // Enables RF24 encryption (all nodes and gateway must have this enabled, and all must be personalized with the same AES key)
    #define MY_RF24_ENCRYPTKEY 0x15,0x12,0x11,0x08,0x01,0x07,0x01,0x03,0x016,0x14,0x15,0x05,0x03,0x09,0x16,0x07
    #ifndef MY_RF24_CHANNEL
    #define MY_RF24_CHANNEL	1

  • @gohan
    Thanks for the code!

    I have been trying to send data from an Uno to a pro mini. Unfortunately, I have been receiving symbols and gibberish on the mini as it has be assigned as a receiver.
    Any clue why?
    I was hoping to send the collected data from the pro mini to the RPi3 via serial gateway and then to Domoticz.

  • Mod

    You probably got the serial port speed wrong on the serial monitor

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