#include <TinyWire.h>

int LED = 8;

void setup() {
  pinMode(LED, OUTPUT); //sets LED as output
  TinyWire.begin(1); //stablish an I2C connection on slave #1
  TinyWire.onReceive( onI2CReceive );//register event
}

void loop() {
}
void onI2CReceive(){
  while(TinyWire.available()){ // while the connection is availabe
    if(TinyWire.read()=='a') // // check if the signal is a
    {
      digitalWrite(LED,HIGH); // Turn LED on
    }
    else{
      digitalWrite(LED,LOW);// Turn LED off
    }
}
}