Radioactive Night Light

A simple blue light with a fading controlled by an Attiny85.

• 1 Attiny85
• 1 LED blue
• 1 switch
• 1 battery holder (CR2032)
• 1 jar
• 1 tracing paper

For the fading, I used an Attiny85

I found a source on https://www.tutorialspoint.com/arduino/arduino_fa... and adjust for my project:

/*
Fade This example shows how to fade an LED using the analogWrite() function. The analogWrite() function uses PWM, so if you want to change the pin you're using, be sure to use another PWM capable pin. On most Arduino, the PWM pins are identified with a "~" sign, like ~3, ~5, ~6, ~9, ~10 and ~11. */

int led = 0; // the PWM pin the LED is attached to
int brightness = 0; // how bright the LED is
int fadeAmount = 5; // how many points to fade the LED by

// the setup routine runs once when you press reset:

void setup() {
// declare pin to be an output:
pinMode(led, OUTPUT);
}
// the loop routine runs over and over again forever:
void loop() {
// set the brightness of pin:
analogWrite(led, brightness);
// change the brightness for next time through the loop:
brightness = brightness + fadeAmount;
// reverse the direction of the fading at the ends of the fade:
if (brightness == 0 || brightness == 255) {
fadeAmount = -fadeAmount ;
}
// wait for 30 milliseconds to see the dimming effect
delay(300);
}

I reused a jar, and put the electronics in the cap.

The tracing paper in the jar blurs the light.