Analog On/Off Switch for ATtiny84

/*
  Analog Input
  Demonstrates analog input by reading an analog sensor on analog pin 0 and
  turning on and off a light emitting diode(LED)  connected to digital pin 0.
  Whether the LED if on for readings below 2.5.V.

  The circuit:
   Potentiometer attached to analog input A1
   center pin of the potentiometer to the analog pin
   one side pin (either one) to ground
   the other side pin to +5V
   LED anode (long leg) attached to digital output 0
   LED cathode (short leg) attached to ground


  Created by David Cuartielles
  modified 12 Feb 2016
  By Ernst Pluess

  This example code is in the public domain.

*/

int sensorPin = A1;    // select the input pin for the potentiometer
int ledPin = 0;      // select the pin for the LED
int sensorValue = 0;  // variable to store the value coming from the sensor

void setup() {
  // declare the ledPin as an OUTPUT:
  pinMode(ledPin, OUTPUT);
}

void loop() {
  // read the value from the sensor:
  sensorValue = analogRead(sensorPin);
  if (sensorValue < 512) {
    // turn the ledPin on
    digitalWrite(ledPin, HIGH);
  }
  else {
    // turn the ledPin off:
    digitalWrite(ledPin, LOW);
  }

}