nRF24L01 not working with basic sketch

Projects Programming
1

I am using 2 x Arduino Nanos and have uploaded the basic sketches as shown:

Transmitter end

/*
* Arduino Wireless Communication Tutorial
*     Example 1 - Transmitter Code
*                
* by Dejan Nedelkovski, www.HowToMechatronics.com
* 
* Library: TMRh20/RF24, https://github.com/tmrh20/RF24/
*/

#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>

RF24 radio(7, 8); // CE, CSN

const byte address[6] = "00001";

void setup() {
  radio.begin();
  radio.openWritingPipe(address);
  radio.setPALevel(RF24_PA_MIN);
  radio.stopListening();
}

void loop() {
  const char text[] = "Hello World";
  radio.write(&text, sizeof(text));
  delay(1000);
}

Receiver end

type /*
* Arduino Wireless Communication Tutorial
*       Example 1 - Receiver Code
*                
* by Dejan Nedelkovski, www.HowToMechatronics.com
* 
* Library: TMRh20/RF24, https://github.com/tmrh20/RF24/
*/

#include <SPI.h>
#include <nRF24L01.h>
#include <RF24.h>

RF24 radio(7, 8); // CE, CSN

const byte address[6] = "00001";

void setup() {
  Serial.begin(9600);
  radio.begin();
  radio.openReadingPipe(0, address);
  radio.setPALevel(RF24_PA_MIN);
  radio.startListening();
}

void loop() {
  if (radio.available()) {
    char text[32] = "";
    radio.read(&text, sizeof(text));
    Serial.println(text);
  }
}

I get nothing on the serial monitor of the receiver side, the baud rate is set correctly.

Connections have been checked and double checked, they are as follows:

Same for both TX & RX

CE - Pin 7
CSN - Pin 8
SCK - Pin 13
MOSI - Pin 11
MISO - Pin 12

If anyone can point me in the right direction, I would be much obliged.

2

Hello
I remember having trouble dealing with those also.
What you can try do to do is

  • don't put the devices to close to each other
  • try to use external power supply
  • add a capacitor between Vcc and Gnd, the closest possible of the radio module
  • set the radio power to the maximum just to test

Are you using fake Arduinos? You can. Just asking because when I tried (a few time ago), it was working with some arduinos, and some others no ; without changing anything but the board

3

Add one bullet point in Post #2:

  • Do not use in a solderless breadboard (because the 2rowx4col pins will be shorted).

(maybe post a picture of your configuration)

4

Anthony,

Many thanks for your very quick reply.

I don't have any capacitors at the minute, will need to order some.
The transmitter side was plugged into a USB charger away from the computer.
They are Nano Clones, I bought a complete kit with two Nanos, two nRF24l01s with separate antennae and two adaptor boards.

Thanks
Steve

5

Thanks for the quick reply, the leads are all directly wired, no breadboard used at all.

Cheers
Steve

6

But where do the radios get their voltage? If you are feeding it from the 5 volt pin, it may not matter what you feed the USB gazinta.

Use a decent power supply and power the module directly if you aren't.

And by "away", just how much distance is between the two radios?

a7

7

a7,

Thanks for your reply, I and using a 3A usb charger for the transmitter, with the receiver being plugged into a USB port on my computer.

The two units are about 1500mm apart.

Cheers
Steve

8

You can't plug the receiver into a USB port! Unless you've omitted something in between the two.

Just confirm you are feeding 5 volts directly from a power supply, not using the 5 volt output of the Arduino board.

OK, that's a start. 3000mm would be better. Even though you

  radio.setPALevel(RF24_PA_MIN);

a7

9

As the RX is displaying data on the Serial Monitor, I fed the Nano of the RX from my computer using the USB lead.
The TX is fed from a 3A USB charger.

To check that the Nanos were working, I loaded the blink sketch onto each and all was well. Following that, I uploaded the TX and RX sketches again. This time, I made sure only the sketch being uploaded was open. Everything is now working correctly.

Thanks for the help
Steve

10

A couple of questions if you don't mind:
1 - Are the power options just MIN and MAX?
2 - Is it trial and error to see what option works? the project I am looking at needs to transmit about 10m maximum through a window.
3 - What size capacitors works best? I have seen a few posts, some use 10 microFarads, some 47 microFarads and others 100 microFarads

Thanks
Steve

11

You can find the answers to most of your questions here:

& here

  1. Also RF24_PA_LOW & RF24_PA_HIGH You can also enable/disable the LNA if using a high powered module: radio.setPALevel(RF24_PA_HIGH, 0); to disable it via the 0.
  2. Pretty much, radio/wireless systems pretty much need to be tested in real life scenarios to see how they function in the environment.
  3. I typically use 10uF, but 47uF will work. 100 is a bit overkill. You see it depends on your power supply, you might not even need them with a solid power supply. In theory you could have a small (100nF) cap, + a large (10-47uF) cap to filter out noise and provide power. If running off batteries for example, a 0-10uF cap should be good.
12

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