Nothing posted in 2020 - well it was that sort of year wasn't it?
Boredom having really set in, 2021 sees me in my Arduino playground. In fact I've been unfaithful and have been using an ESP32 recently, which is quite fun because it has WiFi capabilities - maybe a post about that to follow.
And all that WiFi stuff made me think about my previous delve into the world of radio and so on, using the ubiquitous NRF24L01 Transceiver Module. I bought some of these ages ago, spent days trying to get them to work, eventually succeeded, and, exhausted, then threw them in a box and moved on to something easier.
So, I find them lying in said box... let's have another go. So... I did the classic old-person thing of making all the same mistakes on this attempt as I did on the previous one, what an idiot. Eventually it dawned on me what was going wrong... like last time i had tried to use the TMRh20 library, nRF24L01.h and RF24.h, as nearly everyone seems to do. Trouble is... for me at least, it doesn't work. I mean I suppose it must work for most folk, but not me. No... it was only when I tried the RadioHead offering, RH_NRF24.h, that things started to fall into place.
I am just not technically proficient enough to know why this is, but as soon as I changed to the RadioHead version, I got results. Here are pictures of my two Arduino/NRF24L01 combinations:
//-------------------------------------------------------------------------------
//
// Written by Paul Crossley 16/03/2021
//
// www.magmamon.co.uk
//
//-------------------------------------------------------------------------------
#include <SPI.h>
#include <RH_NRF24.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#define OLED_RESET -1
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
#define SCREEN_ADDRESS 0x3C
RH_NRF24 nrf24(9,10);
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
int count = 0;
int recvd = 0;
int int_value;
unsigned char char_list[4];
boolean oled = true;
int repeat = 20;
long rnd = 0;
union myRandU {long unsignedlongValue; uint8_t bytes[4];} myRand;
// --------------------------------------------------------------------
void setup() {
pinMode(LED_BUILTIN, OUTPUT);
Serial.begin(9600);
Serial.println("RF24...");
if (!nrf24.init()) {
Serial.println("init failed");
} else {
Serial.println("init good");
}
if (!nrf24.setChannel(1)) {
Serial.println("setChannel failed");
} else {
Serial.println("setChannel good");
}
if (!nrf24.setRF(RH_NRF24::DataRate2Mbps, RH_NRF24::TransmitPower0dBm)) {
Serial.println("setRF failed");
} else {
Serial.println("setRF good");
}
if (oled) {
Serial.println("OLED...");
if (!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
Serial.println(F("SSD1306 allocation failed")); for(;;);
}
display.clearDisplay();
display.setTextSize(2);
display.setTextColor(WHITE);
display.setCursor(0,0);
display.println("Listening!");
display.display();
}
Serial.println("Ready!");
}
// --------------------------------------------------------------------
void loop() {
digitalWrite(LED_BUILTIN, HIGH);
count++;
if (count==repeat) {
rnd = random(0,9999);
myRand.unsignedlongValue = rnd;
nrf24.send(myRand.bytes, 4);
nrf24.waitPacketSent();
Serial.print("Sent : ");
Serial.println(rnd);
count=0;
} else {
Serial.print(".");
uint8_t buf[RH_NRF24_MAX_MESSAGE_LEN];
uint8_t len = sizeof(buf);
while (nrf24.waitAvailableTimeout(200) && nrf24.recv(buf, &len)) {
Serial.print("Received : ");
for (int i = 0; i < 4; i++) { char_list[i] = buf[i]; }
memcpy(&int_value, char_list, 4);
Serial.println(int_value);
if (oled) {
recvd++;
display.clearDisplay();
display.setCursor(0,0);
display.println("Listening!");
display.setCursor(0,32);
display.print(recvd);
display.print(": ");
// display.print((char*)buf);
display.print(int_value);
display.display();
}
}
}
digitalWrite(LED_BUILTIN, LOW);
delay(100);
}
