74HC595 Shift Register and LEDs

74HC595 is a Serial to Parallel Converter which has eight outputs (perfect) and three inputs that you use to feed data into it a bit at a time.

This chip makes it a little slower to drive the LEDs (you can only change the LEDs about 500,000 times a second instead of 8,000,000 a second) but it's still really fast, way faster than humans can detect, so it's worth it.

74HC595 shift register is a type of chip that holds what can be thought of as eight memory locations, each of which can either be a 1 or a 0. To set each of these values on or off, we feed in the data using the 'Data' and 'Clock' pins of the chip.

Active and passive buzzer

The difference between the active buzzer and passive buzzer is that an active buzzer has a built-in oscillating source, so it will generate a sound when electrified.

A passive buzzer does not have such a source so it will not tweet if DC signals are used; instead, you need to use square waves whose frequency is between 2K and 5K to drive it. The active buzzer is often more expensive than the passive one because of multiple built-in oscillating circuits.

Tilt ball switch

Tilt sensors allow you to detect orientation or inclination.

They are usually made up of a cavity of some sort with a non-conductive mass inside, such as a blob of mercury or rolling ball. One end of the cavity has two conductive elements (poles). When the sensor is oriented so that that end is downwards, the mass rolls onto the poles and shorts them, acting as a switch throw.