1. Download RadioHead library: Go to:
Unzip and copy it into Arduino library folder:
Now you should to see RadioHead example code:
2. Transmitter module:
Antenna lenght depens do you have 315, 330 or 433 MHz module. Best is to use the antenna of 1/4 wavelength (or 1/2, 1/8).
Online calculator: http://www.onlineconversion.com/frequency_wavelength.htm
- 315MHz wavelenght is 0.95 m, 1/4 = 23.75 cm
- 330MHz wavelenght is 0.91 m, 1/4 = 22.75 cm
- 433MHz wavelenght is 0.69 m, 1/4 = 17.25 cm
Youse single core wire. Antennas should be on same orientations. Both of them horizontal or vertical.
3. Receiver module
4. Transmitter test circuit
#include <RH_ASK.h>
#include <SPI.h>
const char *message = "";
int button = 2;
RH_ASK driver;
void setup() {
Serial.begin(9600); // Debugging only
if (!driver.init()){
Serial.println("init of receiver failed");
}
pinMode(button,INPUT);
}
void loop(){
if (digitalRead(button) == HIGH){
message="a";
driver.send((uint8_t *)message, strlen(message)); // send the message
driver.waitPacketSent(); // Wait until the whole message is gone
Serial.println(message);
Serial.println(strlen(message));
delay(2000);
}
else{
//Serial.println("Low");
}
}
5. Receiver test circuit
#include <RH_ASK.h>
#include <SPI.h>
RH_ASK driver; //pin 12
// RH_ASK driver(2000, 2, 4, 5); // ESP8266: do not use pin 11
int ledPassive = 5; //standby light
int ledActive = 7; //green LED's
void setup()
{
pinMode(ledPassive,OUTPUT);
pinMode(ledActive,OUTPUT);
Serial.begin(9600); // Debugging only
if (!driver.init())
Serial.println("init of receiver failed");
}
void loop()
{
digitalWrite(ledPassive,HIGH);
noTone(8);
digitalWrite(ledActive,LOW);
uint8_t buf[RH_ASK_MAX_MESSAGE_LEN];
uint8_t buflen = sizeof(buf);
if (driver.recv(buf, &buflen)) { // if message received
for(int i=0;i<sizeof(buf);i++){
Serial.print(char(buf[i])); //test display output
}
if(buf[0]=='a'){ // and if the first letter in message array is X
digitalWrite(ledPassive,LOW);
for(int i=0;i<10;i++){ // loop alternates between LED and buzzer
digitalWrite(ledActive,HIGH);
tone(8, 262); //pin 8
delay(100);
}
}
else if(buf[0]!='a'){
digitalWrite(ledPassive,HIGH);
noTone(8);
}
}
}
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