Sometimes a full size Arduino is a bit on an overkill if for example you just want to blink one LED.

Fortunately there is a smaller and cheaper version of microcontroller used by Arduino called the ATtiny. We have included one in the workshop kit, it's a small 8 pin chip that is stuck into a foam pad.

You can program this chip using your Arduino. Instructions are provided here and you need to follow the sections relevant to using Arduino (as ISP) to an ATtiny.

Easier (1) Flash an LED on/off once a second using just your ATtiny. Intermediate (2) Adjust the speed of flashing by using a potentiometer (ask a helper for one if you don't have one from a previous workshop kit.)