I wrote a little program and made a circuit for the ATTiny which enables a photocell to control an LED and a motor with pulse width modulation.

Here’s the video:

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And here’s the circuit diagram:

And here’s the code for the Arduino IDE:

int val = 0;
int qval = 0;

void setup(){
  pinMode(1,OUTPUT);
  digitalWrite(1,LOW);
  
  pinMode(0,OUTPUT);
  digitalWrite(0,LOW);  
}

void loop(){
  val = analogRead(1);
  qval = int(val/4);
  if (val<200){
    qval = 0;
  }
  analogWrite(1,qval);
  analogWrite(0,qval);
}

The LED doesn’t seem to ‘fade’ on. Rather, it seems to come on suddenly.