Battery & case
The coin-cell battery lasts approximately 3 years if the Turtle is pressed twice a day. It is full encased in epoxy so it is safe for children. As a result, unfortunately, the battery cannot be replaced. The epoxy case is water-resistant, not water proof. It can be in the shower on a wall not directly under the shower head
We use Orange, Red, Green & Yellow LEDs. Each light represents one part of the mouth, upper left, upper right, lower right, lower left. We tried a 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.
The microchip is programmed to blink each light for 30 seconds, the next light blinking faster than the one before, with a final victory lap of all the lights. The starting position is random each time, so your child brushes in a different pattern. The micro chip is an ATtiny85 and is programmed with Arduino software.