A simple project to flash some LEDs as is traditional at this time of year.
I took a Adafruit Trinket which is an ATTiny based board and added some transistors as simple open collector drivers. The resistors were carefully calculated by just grabbing a bunch that came with the bag of LEDs, just looking at the photo it looks like they are 200Ω
The trinket is a bit of a tricky beast to program compared to the Uno but the details are all covered on the Adafruit pages. You need to configure the IDE to have the board definitions and install a driver. You'll also likely to need to run the IDE as root/admin otherwise it does not communicate with the driver. You then switch to the USBTinyISP programmer and select AdaFruitTrinket in the board menu.
To program you have to reset the board before pressing the upload button, as you only have 10s to do that it might be worth compiling first before pressing reset.
int LED1 = 0;
int LED2 = 1;
int LED3 = 2;
int LEDSpeed = 200;
void setup() {
pinMode(LED1, OUTPUT);
pinMode(LED2, OUTPUT);
pinMode(LED3, OUTPUT);
}
void loop() {
digitalWrite(LED1, HIGH);
delay(LEDSpeed);
digitalWrite(LED3, LOW);
delay(LEDSpeed);
digitalWrite(LED2, HIGH);
delay(LEDSpeed);
digitalWrite(LED1, LOW);
delay(LEDSpeed);
digitalWrite(LED3, HIGH);
delay(LEDSpeed);
digitalWrite(LED2, LOW);
delay(LEDSpeed);
}
