From this set, you can build a circuit that simulates the movement of sand grains in traditional hourglasses with LEDs. Counting can be restarted by reversing the hourglass, and its speed can be regulated with a potentiometer.

Specifications:

- Operating voltage: 3.3...5V DC
- Preparation time: 40 minutes
- Dimensions: 74.4 x 43.7 x 24mm

For assembly you also need:

- soldering iron and tin,
- side hip pliers,
- tweezers,
- multimeter or knowledge of standard value marking of components.