I am having issues getting the NRF24L01 to reliably transmit data. I am building a project for a one way road leading into a camp. The idea is for there to be 5 sensors along the road that have IP66 HC-SR04 IP66 ultrasound sensors on them. They will transmit back to a single node, which can also communicate with another node. The other 2 nodes will have LEDs on them outlining stop signs so when a vehicle comes into the property, a stop sign on the other side lights up telling people to not enter. (It is a one-lane road that has high fences on both sides for about 500 ft, backing up is difficult, so thus the warning system.)
I took a RF24 test and an Ultrasonic HC-SR04 codes and mashed them together. The idea is that each sensor will transmit when it detects something in its path (the road being about 450 [15 ft] across), so it transmits data when the received distance is between 45 cm and 300cm, and other times not transmit. Each sensor when it transmits that data, will include an array of 3 items. The sending units node number, the distance in centimeters and the transmit millis time. The array is set as an unsigned long array, and the Arduinos are Nano. Each Arduino will be powered by a Solar charge controller and a 3.7V 5000mAh battery (connected to a 6 watt solar panel).
This seems like it should be easy.... but I am having trouble even getting this to transmit across a rather short distance with both Nanos attached to my laptop.
Testing everything at the moment, this node will eventually be 011, but for now, I am marking it 00.
#include <RF24.h>
#include <RF24Network.h>
#include <SPI.h>
RF24 radio(10, 9); // nRF24L01 (CE,CSN)
RF24Network network(radio); // Include the radio in the network
const uint16_t this_node = 00; // Office Base node
const uint16_t node01 = 01; // Inside Stop Sign
const uint16_t node011 = 011; // Inside First Sensor
const uint16_t node012 = 012; // Inside Second Sensor
const uint16_t node013 = 013; // Middle Sensor
const uint16_t node014 = 014; // Outside Second Sensor
const uint16_t node015 = 015; // Outside First Sensor
const uint16_t node02 = 02; // Outside Stop Sign
const unsigned long interval = 25; //How often to send data to the other unit (ms)
unsigned long last_sent;
unsigned long transmitData[] = {0, 0, 0}; // 1st is contents of distance, 2nd is location, 3rd is time sent
int transmit_node = 00; // Node doing transmission
#define debug // trigger debug serial monitor messages.
#define echoPin 2 // attach pin D2 Arduino to pin Echo of HC-SR04
#define trigPin 3 //attach pin D3 Arduino to pin Trig of HC-SR04
long duration; // variable for the duration of sound wave travel
int distance; // variable for the distance (centimeters) measurement
float distanceft; // variable for the distance (feet) measurement
int getMeasurement() {
// Clears the trigPin condition
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
// Sets the trigPin HIGH (ACTIVE) for 10 microseconds
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
// Reads the echoPin, returns the sound wave travel time in microseconds
duration = pulseIn(echoPin, HIGH);
// Calculating the distance
// Calculating the distance
distance = duration * 0.034 / 2; // Speed of sound wave divided by 2 (go and back)
distanceft = distance * 0.0328084;
}
void setup() {
SPI.begin();
radio.begin();
network.begin(90, this_node); //(channel, node address)
radio.setDataRate(RF24_2MBPS);
transmit_node = 0;
pinMode(trigPin, OUTPUT); // Sets the trigPin as an OUTPUT
pinMode(echoPin, INPUT); // Sets the echoPin as an INPUT
#ifdef debug
Serial.begin(115200); // // Serial Communication is starting with 115200 of baudrate speed
Serial.println("Ultrasonic Sensor HC-SR04 Test"); // print some text in Serial Monitor
Serial.println("with Arduino Nano");
#endif
}
void loop() {
getMeasurement();
// Prints the distance on the Serial Monitor
if (distance != 0) {
// continue only if get a valid reading.
if (distanceft > 15) {
// Nothing in road
#ifdef debug
Serial.print(F("NO VEHICLE -- Distance: "));
Serial.print(distance);
Serial.print(F(" cm; "));
Serial.print(distanceft);
Serial.println(F(" feet"));
#endif
} else if (distance < 20) {
// Something is too close
#ifdef debug
Serial.print(F("TOO CLOSE!! - Distance: "));
Serial.print(distance);
Serial.print(F(" cm; "));
Serial.print(distanceft);
Serial.println(F(" feet"));
#endif
} else {
unsigned long now = millis();
if (now - last_sent >= interval) {
last_sent = now;
// Sweet spot send data on network
#ifdef debug
Serial.print(F("Sweet Spot -- Distance: "));
Serial.print(distance);
Serial.print(F(" cm; "));
Serial.print(distanceft);
Serial.print(F(" feet"));
#endif
// distance from sensor to object is
transmitData[0] = distance;
transmitData[1] = transmit_node;
transmitData[2] = now;
network.update();
RF24NetworkHeader header(node01); // (Address where the data is going)
bool ok = network.write(header, &transmitData, sizeof(transmitData)); // Send the data
delay(250);
#ifdef debug
Serial.print(F(" -- Data sent ("));
Serial.print(transmitData[2]);
Serial.print(F(") "));
#endif
unsigned long now = millis();
if (now - last_sent >= interval) {
last_sent = now;
}
if (ok) {
Serial.println(F("ACK Rec"));
} else {
Serial.println(F("TX Failed"));
}
}
}
}
delay(2500);
}
Here is the receive node:
#include <RF24.h>
#include <RF24Network.h>
#include <SPI.h>
RF24 radio(10, 9); // nRF24L01 (CE,CSN)
RF24Network network(radio); // Include the radio in the network
const uint16_t this_node = 01; // Office Base node
const uint16_t node011 = 011; // Inside First Sensor
const uint16_t node012 = 012; // Inside Second Sensor
const uint16_t node013 = 013; // Middle Sensor
const uint16_t node014 = 014; // Outside Second Sensor
const uint16_t node015 = 015; // Outside First Sensor
const uint16_t node02 = 02; // Outside Stop Sign
#define debug // trigger debug serial monitor messages.
int transmit_node = 01;
void setup() {
SPI.begin();
radio.begin();
network.begin(90, this_node); //(channel, node address)
radio.setDataRate(RF24_2MBPS);
#ifdef debug
Serial.begin(115200); // // Serial Communication is starting with 9600 of baudrate speed
Serial.println("One Way Traffic Controller"); // print some text in Serial Monitor
Serial.println("with Arduino Nano");
#endif
}
void loop() {
network.update();
while (network.available()) {
RF24NetworkHeader header;
unsigned long incomingData[] = {0,0,0};
unsigned long Distance;
unsigned int receiveNode;
network.read(header, &incomingData, sizeof(incomingData));
Serial.print(F("Incoming (from "));
Serial.print(incomingData[1]);
Serial.print(F("): "));
Serial.print(incomingData[0]);
Serial.print(F(" cm -- transmitted at: "));
Serial.print(incomingData[2]);
Serial.println(F(")"));
}
}