The coin cell battery lasts 3 years if the Turtle is pressed twice a day. It is full encased so it is safe for children.
We use Orange, Red, Green & yellow LEDs. We tried blue LED but it wore out the battery twice as quickly as the other colors. It was hard to let the blue go but we thought the longer battery life was worth it.
Programmed with Arduino software, this microchip is programmed to have a random start with 4 30 second lights, each one faster than the other and a final victory lap of all the lights.