RCSwitch on Attiny85

Question

I would like to use my Attiny85 as an remote controlled relay switch. I have already tested the sketch on my Atmega328 and it worked. Now I wanted to burn the sketch on my Attiny85 using ArduinoISP but I get the following error in the ArduinoIDE:

sketch_dec25a.ino: In function ‘void setup()’:
sketch_dec25a:13: error: ‘class RCSwitch’ has no member named ‘enableReceive’
sketch_dec25a.ino: In function ‘void loop()’:
sketch_dec25a:20: error: ‘class RCSwitch’ has no member named ‘available’
sketch_dec25a:21: error: ‘class RCSwitch’ has no member named ‘getReceivedValue’
sketch_dec25a:22: error: ‘class RCSwitch’ has no member named ‘getReceivedValue’
sketch_dec25a:25: error: ‘class RCSwitch’ has no member named ‘resetAvailable’

That's my code:

#include <SoftwareSerial.h>
#include <RCSwitch.h>

int RELAY_PIN = 2;

RCSwitch mySwitch = RCSwitch();
SoftwareSerial mySerial(1, 3); // RX, TX

void setup()  
{
  pinMode(RELAY_PIN, OUTPUT);
  mySwitch.enableReceive(0);  // Receiver on inerrupt 0 => that is pin #2
  mySerial.begin(9600);
  mySerial.println("Hello, world?");
}

void loop() // run over and over
{
  if (mySwitch.available()) {
    Serial.println(mySwitch.getReceivedValue());
    if(mySwitch.getReceivedValue() == 1234567){
      digitalWrite(RELAY_PIN, HIGH);
    }
    mySwitch.resetAvailable();
  }
}

I am using these cores: https://code.google.com/p/arduino-tiny/

I am using the SoftwareSerial just for debugging. Sorry for my bad english and thanks for your help!

Answer 1

The issue you face is that RCSwitch does not seem to support receive mode for ATtiny.

This is what you can find in RCSwitch.h:

// At least for the ATTiny X4/X5, receiving has to be disabled due to
// missing libm depencies (udivmodhi4)
#if defined( __AVR_ATtinyX5__ ) or defined ( __AVR_ATtinyX4__ )
#define RCSwitchDisableReceiving
#endif

Then all methods related to receptions are not defined in RCSwitch class for ATtiny MCUs:

#if not defined( RCSwitchDisableReceiving )
void enableReceive(int interrupt);
void enableReceive();
void disableReceive();
bool available();
void resetAvailable();

unsigned long getReceivedValue();
unsigned int getReceivedBitlength();
unsigned int getReceivedDelay();
unsigned int getReceivedProtocol();
unsigned int* getReceivedRawdata();
#endif

I am really not sure if there is a way to work around it, I have not looked at the code in RCSwitch.cpp.

Maybe you best option would be to find another RC library.

For instance, if you can use Infra-Red RC, then there are libraries out there that could work for ATtiny:

https://github.com/shirriff/Arduino-IRremote

Answer 2

I have tested with Digispark ATtiny85 and https://github.com/sui77/rc-switch work perfect

just comment #define RCSwitchDisableReceiving than use in setup code enableReceive(0); and external pin 7 PB2(int0) as RF source

Or you can use other software pin interrupt

in setup: PCMSK |= (1<<PCINT0);//here pin number GIMSK |= (1<<PCIE);

interrupt function ISR(PCINT0_vect) { rd.handleInterrupt(); // you need also put handleInterrupt() in public section in RCSwitch.h }