These 5 insider facts will reveal how lottery number draw machines really work

German lotto presenter Heike Maurer with gravity pick lottery machines.

Trust plays a big part in the lottery business. And because of this, the most scrutinized part of the lottery draw is the physical machines that pick the balls.

Here are 5 facts about these modern machine marvels of randomness:

#1. There are two main types of Lotto machines: gravity pick and air mix. Both types have a few things in common:

  • They are designed and proven using statistical analysis to produce random combinations of numbers.

  • The balls are always visible during the mixing and drawing process - they never disappear inside tubes or chambers. This helps prevent tampering; and since the drawings are televised live, it gives the viewer confidence that the drawing is not being fixed.


The Mega Millions gravity pick machine in operation.

#2. The gravity-pick machine is perceived to be more secure than the air-mix machine.

#3. One common type of gravity-pick machine uses solid rubber balls.

The balls are dropped into a chamber where two paddles spin in opposite directions and mix the balls.

The operator opens a sliding door at the bottom of the mixing chamber, and one at a time, six balls pass through a clear tube into a clear display area where the numbers can be read.

Another common type of gravity-pick machine.

An optical sensor detects the passage of each ball, allowing only the correct number of balls to pass through the doorway.

#4. The other type of machine that is commonly used for Lotto is the air-mix machine.

It uses ping-pong balls that are painted with numbers and carefully calibrated for size and weight.

These balls are released into the machine and jets of air blow up through the chamber to mix them.

An example of the air-mix machine for the Gibralta Lottery.

#5. To select a set of balls for the air-mix machine, the operator opens a valve that allows air out of the machine through a set of tubes near the top of the machine.

Once the valve is open, balls are blown into the tube and are then transferred through another clear tube into a display area for reading.

Source: How Stuff Works