Logic gates

How does the exhibit work?

Try to find a way to keep the wheel spinning. You can try different things like pressing the switch, entering the correct code, scanning your fingerprint and holding your hand between the light lock.

What is the science behind it?

A computer receives a lot of information (the input). This information is processed and that yields a given result (the output). The computer cannot do this just like that. It uses the logic gates AND, OR and NOT.

With this exhibit, you can test how gates like this work. You have four types of input, which you can turn “on” in various ways:

• A photo-interrupter: hold your hand in between

• A keyboard: enter the correct code

• A fingerprint scanner: place the tip of your finger on it

• A switch: press it

  With the AND gate, the output will start up (the Ferris wheel will turn) if input 1 AND input 2 are on. With the OR gate, input 1 OR input 2 must be on. Finally, with the NOT gate, the output only starts up if the input is on NOT.

  Need an extra challenge? Put the cable at the end of the AND gate in the OR or NOT gate. When does the Ferris wheel turn?

Educational material (1st grade secondary school)

Let your students further explore their engineering skills through logic gates and sensors. Go to www​.brightbib​.be.

Logic gates with safes

Banks find logic gates like this handy, too. Suppose a bank only wants a safe to open when its staff:

• scan their fingerprint
  AND

• enter the correct code.

In this case, they use a fingerprint scanner and a keyboard as input sorts. They connect these to the AND gate. The output is the safe. If the staff do both, then both inputs are “on” and the safe opens.

If a thief has obtained the right code, but doesn’t have the right fingerprint, then the safe stays shut.

AND, OR and NOT in search engines

Imagine: you are looking for fun Technopolis experiments that you can do.

• Type ‘Technopolis experiments’ in Google. Then for Google that’s an “AND”. You get what you are looking for.

• Type ‘Technopolis OR experiments’? Then that’s an “OR”. You get information about Technopolis, information about experiments and information about Technopolis experiments.

• Type ‘Technopolis -experiments’? Then it’s a “NOT”. You only get information about Technopolis and nothing about experiments.