ESP32: nRF24L01 receives no data

Question

Using two, nRF24L01 with two, ESP32 DEVKIT V1. Trying to setup RF24 Library example, "Getting Started". Able to transmit on both nodes, however, there is no payload received when switching to receive while transmitting on both nodes.

SPI pins used:
MOSI = GPIO23,
MISO = GPIO19,
SCK = GPIO18,
CE = GPIO21,
CSN = GPIO5,
IRQ = No connection,
Vcc = 5.0 V using piggyback adapter with 3.3 V regulator,
GND = Ground.

Are the SPI pins used correctly for the ESP32 DEVKIT V1?

<script src="https://gist.github.com/Tech500/b57d4d356baaec48adc41196117c02aa.js"></script>
nRF24L01 Project for use with ESP32 DEVKIT V1
Details.txt
//Getting Started exammple: Details Radio_0 and Radio_1.
RF24/examples/GettingStarted
Which radio is this? Enter '0' or '1'. Defaults to '0'
radioNumber = 0
*** PRESS 'T' to begin transmitting to the other node
SPI Frequency = 10 Mhz
Channel = 76 (~ 2476 MHz)
Model = nRF24L01+
RF Data Rate = 1 MBPS
RF Power Amplifier = PA_LOW
RF Low Noise Amplifier = Enabled
CRC Length = 16 bits
Address Length = 5 bytes
Static Payload Length = 4 bytes
Auto Retry Delay = 1500 microseconds
Auto Retry Attempts = 15 maximum
Packets lost on
 current channel = 0
Retry attempts made for
 last transmission = 0
Multicast = Disabled
Custom ACK Payload = Disabled
Dynamic Payloads = Disabled
Auto Acknowledgment = Disabled
Primary Mode = TX
TX address = 0x65646f4e31
pipe 0 ( open ) bound = 0x65646f4e31
pipe 1 ( open ) bound = 0x65646f4e32
pipe 2 (closed) bound = 0xc3
pipe 3 (closed) bound = 0xc4
pipe 4 (closed) bound = 0xc5
pipe 5 (closed) bound = 0xc6
-------------------------------------
radioNumber = 1
*** PRESS 'T' to begin transmitting to the other node
SPI Frequency = 10 Mhz
Channel = 76 (~ 2476 MHz)
Model = nRF24L01+
RF Data Rate = 1 MBPS
RF Power Amplifier = PA_LOW
RF Low Noise Amplifier = Enabled
CRC Length = 16 bits
Address Length = 5 bytes
Static Payload Length = 4 bytes
Auto Retry Delay = 1500 microseconds
Auto Retry Attempts = 15 maximum
Packets lost on
 current channel = 0
Retry attempts made for
 last transmission = 0
Multicast = Disabled
Custom ACK Payload = Disabled
Dynamic Payloads = Disabled
Auto Acknowledgment = Disabled
Primary Mode = RX
TX address = 0x65646f4e32
pipe 0 (closed) bound = 0x65646f4e32
pipe 1 ( open ) bound = 0x65646f4e31
pipe 2 (closed) bound = 0xc3
pipe 3 (closed) bound = 0xc4
pipe 4 (closed) bound = 0xc5
pipe 5 (closed) bound = 0xc6
Radio_0.ino

RF24 Library example "Getting Started":

/*
 * See documentation at https://nRF24.github.io/RF24
 * See License information at root directory of this library
 * Author: Brendan Doherty (2bndy5)
 */
/**
 * A simple example of sending data from 1 nRF24L01 transceiver to another.
 *
 * This example was written to be used on 2 devices acting as "nodes".
 * Use the Serial Monitor to change each node's behavior.
 * 
 * TX Code --Radio 0
 */
/* 
 Coded for a ESP32 DEVKIT V1 board type to make use of a pair of 
 nRF24L01+ 2.4 GHz. Transceivers
 SPI Pins used MOSI = 23, CE = 21, MSIO = 19, SCK = 18, CSN = 4
 This code is for Radio 0.
 William Lucid
*/
#include <SPI.h>
#include "printf.h"
#include "RF24.h"
#define CE_PIN 21
#define CSN_PIN 5
// instantiate an object for the nRF24L01 transceiver
RF24 radio(CE_PIN, CSN_PIN);
// Let these addresses be used for the pair
uint8_t address[][6] = { "1Node", "2Node" };
// It is very helpful to think of an address as a path instead of as
// an identifying device destination
// to use different addresses on a pair of radios, we need a variable to
// uniquely identify which address this radio will use to transmit
bool radioNumber = 0; // 0 uses address[0] to transmit, 1 uses address[1] to transmit
// Used to control whether this node is sending or receiving
bool role = true; // true = TX role, false = RX role
// For this example, we'll be using a payload containing
// a single float number that will be incremented
// on every successful transmission
float payload = 0.0;
void setup() {
 Serial.begin(115200);
 while (!Serial) {
 // some boards need to wait to ensure access to serial over USB
 }
 pinMode(CE_PIN, OUTPUT);
 pinMode(CSN_PIN, OUTPUT);
 // initialize the transceiver on the SPI bus
 if (!radio.begin()) {
 Serial.println(F("radio hardware is not responding!!"));
 while (1) {} // hold in infinite loop
 }
 //radio.setAutoAck(false);
 // print example's introductory prompt
 Serial.println(F("RF24/examples/GettingStarted"));
 // To set the radioNumber via the Serial monitor on startup
 Serial.println(F("Which radio is this? Enter '0' or '1'. Defaults to '0'"));
 while (!Serial.available()) {
 // wait for user input
 }
 char input = Serial.parseInt();
 radioNumber = input == 1;
 Serial.print(F("radioNumber = "));
 Serial.println((int)radioNumber);
 // role variable is hardcoded to RX behavior, inform the user of this
 Serial.println(F("*** PRESS 'T' to begin transmitting to the other node"));
 // Set the PA Level low to try preventing power supply related problems
 // because these examples are likely run with nodes in close proximity to
 // each other.
 radio.setPALevel(RF24_PA_LOW); // RF24_PA_MAX is default.
 // save on transmission time by setting the radio to only transmit the
 // number of bytes we need to transmit a float
 radio.setPayloadSize(sizeof(payload)); // float datatype occupies 4 bytes
 // set the TX address of the RX node into the TX pipe
 radio.openWritingPipe(address[radioNumber]); // always uses pipe 0
 // set the RX address of the TX node into a RX pipe
 radio.openReadingPipe(1, address[!radioNumber]); // using pipe 1
 // additional setup specific to the node's role
 if (role) {
 radio.stopListening(); // put radio in TX mode
 } else {
 radio.startListening(); // put radio in RX mode
 }
 // For debugging info
 printf_begin(); // needed only once for printing details
 // radio.printDetails(); // (smaller) function that prints raw register values
 radio.printPrettyDetails(); // (larger) function that prints human readable data
} // setup
void loop() {
 if (role) {
 // This device is a TX node
 unsigned long start_timer = micros(); // start the timer
 bool report = radio.write(&payload, sizeof(float)); // transmit & save the report
 unsigned long end_timer = micros(); // end the timer
 if (report) {
 Serial.print(F("Transmission successful! ")); // payload was delivered
 Serial.print(F("Time to transmit = "));
 Serial.print(end_timer - start_timer); // print the timer result
 Serial.print(F(" us. Sent: "));
 Serial.println(payload); // print payload sent
 payload += 0.01; // increment float payload
 } else {
 Serial.println(F("Transmission failed or timed out")); // payload was not delivered
 }
 // to make this example readable in the serial monitor
 delay(1000); // slow transmissions down by 1 second
 } else {
 // This device is a RX node
 uint8_t pipe;
 if (radio.available(&pipe)) { // is there a payload? get the pipe number that recieved it
 uint8_t bytes = radio.getPayloadSize(); // get the size of the payload
 radio.read(&payload, bytes); // fetch payload from FIFO
 Serial.print(F("Received "));
 Serial.print(bytes); // print the size of the payload
 Serial.print(F(" bytes on pipe "));
 Serial.print(pipe); // print the pipe number
 Serial.print(F(": "));
 Serial.println(payload); // print the payload's value
 }
 } // role
 if (Serial.available()) {
 // change the role via the serial monitor
 char c = toupper(Serial.read());
 if (c == 'T' && !role) {
 // Become the TX node
 role = true;
 Serial.println(F("*** CHANGING TO TRANSMIT ROLE -- PRESS 'R' TO SWITCH BACK"));
 radio.stopListening();
 } else if (c == 'R' && role) {
 // Become the RX node
 role = false;
 Serial.println(F("*** CHANGING TO RECEIVE ROLE -- PRESS 'T' TO SWITCH BACK"));
 radio.startListening();
 }
 }
} // loop

Radio_1.ino:

/*
 * See documentation at https://nRF24.github.io/RF24
 * See License information at root directory of this library
 * Author: Brendan Doherty (2bndy5)
 */
/**
 * A simple example of sending data from 1 nRF24L01 transceiver to another.
 *
 * This example was written to be used on 2 devices acting as "nodes".
 * Use the Serial Monitor to change each node's behavior.
 */
 /* 
 Coded for a ESP32 DEVKIT V1 board type to make use of a pair of 
 nRF24L01+ 2.4 GHz. Transceivers
 SPI Pins used MOSI = 23, CE = 21, MSIO = 19, SCK = 18, CSN = 4
 This code is for Radio 1.
 
*/
#include <SPI.h>
#include "printf.h"
#include "RF24.h"
#define CE_PIN 21
#define CSN_PIN 5
// instantiate an object for the nRF24L01 transceiver
RF24 radio(CE_PIN, CSN_PIN);
// Let these addresses be used for the pair
uint8_t address[][6] = { "1Node", "2Node" };
// It is very helpful to think of an address as a path instead of as
// an identifying device destination
// to use different addresses on a pair of radios, we need a variable to
// uniquely identify which address this radio will use to transmit
bool radioNumber = 1; // 0 uses address[0] to transmit, 1 uses address[1] to transmit
// Used to control whether this node is sending or receiving
bool role = false; // true = TX role, false = RX role
// For this example, we'll be using a payload containing
// a single float number that will be incremented
// on every successful transmission
float payload = 0.0;
void setup() {
 Serial.begin(115200);
 while (!Serial) {
 // some boards need to wait to ensure access to serial over USB
 }
 pinMode(CE_PIN, OUTPUT);
 pinMode(CSN_PIN, OUTPUT);
 // initialize the transceiver on the SPI bus
 if (!radio.begin()) {
 Serial.println(F("radio hardware is not responding!!"));
 while (1) {} // hold in infinite loop
 }
 radio.setAutoAck(false);
 // print example's introductory prompt
 Serial.println(F("RF24/examples/GettingStarted"));
 // To set the radioNumber via the Serial monitor on startup
 Serial.println(F("Which radio is this? Enter '0' or '1'. Defaults to '0'"));
 while (!Serial.available()) {
 // wait for user input
 }
 char input = Serial.parseInt();
 radioNumber = input == 1;
 Serial.print(F("radioNumber = "));
 Serial.println((int)radioNumber);
 // role variable is hardcoded to RX behavior, inform the user of this
 Serial.println(F("*** PRESS 'T' to begin transmitting to the other node"));
 // Set the PA Level low to try preventing power supply related problems
 // because these examples are likely run with nodes in close proximity to
 // each other.
 radio.setPALevel(RF24_PA_LOW); // RF24_PA_MAX is default.
 // save on transmission time by setting the radio to only transmit the
 // number of bytes we need to transmit a float
 radio.setPayloadSize(sizeof(payload)); // float datatype occupies 4 bytes
 // set the TX address of the RX node into the TX pipe
 radio.openWritingPipe(address[radioNumber]); // always uses pipe 0
 // set the RX address of the TX node into a RX pipe
 radio.openReadingPipe(1, address[!radioNumber]); // using pipe 1
 // additional setup specific to the node's role
 if (role) {
 radio.stopListening(); // put radio in TX mode
 } else {
 radio.startListening(); // put radio in RX mode
 }
 // For debugging info
 printf_begin(); // needed only once for printing details
 // radio.printDetails(); // (smaller) function that prints raw register values
 radio.printPrettyDetails(); // (larger) function that prints human readable data
} // setup
void loop() {
 if (role) {
 // This device is a TX node
 unsigned long start_timer = micros(); // start the timer
 bool report = radio.write(&payload, sizeof(float)); // transmit & save the report
 unsigned long end_timer = micros(); // end the timer
 if (report) {
 Serial.print(F("Transmission successful! ")); // payload was delivered
 Serial.print(F("Time to transmit = "));
 Serial.print(end_timer - start_timer); // print the timer result
 Serial.print(F(" us. Sent: "));
 Serial.println(payload); // print payload sent
 payload += 0.01; // increment float payload
 } else {
 Serial.println(F("Transmission failed or timed out")); // payload was not delivered
 }
 // to make this example readable in the serial monitor
 delay(1000); // slow transmissions down by 1 second
 } else {
 // This device is a RX node
 uint8_t pipe;
 if (radio.available(&pipe)) { // is there a payload? get the pipe number that recieved it
 uint8_t bytes = radio.getPayloadSize(); // get the size of the payload
 radio.read(&payload, bytes); // fetch payload from FIFO
 Serial.print(F("Received "));
 Serial.print(bytes); // print the size of the payload
 Serial.print(F(" bytes on pipe "));
 Serial.print(pipe); // print the pipe number
 Serial.print(F(": "));
 Serial.println(payload); // print the payload's value
 }
 } // role
 if (Serial.available()) {
 // change the role via the serial monitor
 char c = toupper(Serial.read());
 if (c == 'T' && !role) {
 // Become the TX node
 role = true;
 Serial.println(F("*** CHANGING TO TRANSMIT ROLE -- PRESS 'R' TO SWITCH BACK"));
 radio.stopListening();
 } else if (c == 'R' && role) {
 // Become the RX node
 role = false;
 Serial.println(F("*** CHANGING TO RECEIVE ROLE -- PRESS 'T' TO SWITCH BACK"));
 radio.startListening();
 }
 }
} // loop

Video confirming transmission; both radios

Answer 1

SPI pins are correct for ESP32 DEVKIT V1; I have it both transmitting and receiving now.

I swapped out all Dupont wiring longer than 10 cm, changed the channel with the radio.setChannel function to 125 on both transmitter and receiver, and added a 100 μF, 16 V electrolytic capacitor between the 5 V rail and ground.

Transmission successful! Time to transmit = 403 us. Sent: 5.96
Transmission successful! Time to transmit = 403 us. Sent: 5.97
Transmission successful! Time to transmit = 403 us. Sent: 5.98
Transmission successful! Time to transmit = 403 us. Sent: 5.99
Transmission successful! Time to transmit = 403 us. Sent: 6.00
Transmission successful! Time to transmit = 403 us. Sent: 6.01
Transmission successful! Time to transmit = 403 us. Sent: 6.02
Transmission successful! Time to transmit = 403 us. Sent: 6.03
Transmission successful! Time to transmit = 403 us. Sent: 6.04
Received 4 bytes on pipe 1: 6.25
Received 4 bytes on pipe 1: 6.26
Received 4 bytes on pipe 1: 6.27
Received 4 bytes on pipe 1: 6.28
Received 4 bytes on pipe 1: 6.29
Received 4 bytes on pipe 1: 6.30

Code Gists for nRF24L01, transmit and receive radios