(upbeat pop music)

Welcome back to CS First Scratch Music and Sound where you can use computer science to make creative projects involving sound.

Today you will make a DJ mixing tool.

DJ's use scratching techniques and digital mixing boards to build their own music.

They incorporate sounds sampled from other songs and mix them to a beat that people can dance to.

During a dance party, DJ's use mixing boards to adjust their music choices, sample selections, and scratching techniques to engage an audience.

DJ's even battle at worldwide events where they are given a limited amount of time, usually anywhere from 30 seconds to a couple of minutes to show off their skills.

But did you know that the mixing board that makes all of this possible is actually a type of computer that uses technology built my computer scientists.

Let's take a look at some DJ's and notice how they use technology to create music.

(energetic electronic music)

(exciting techno music)

(upbeat dance music)

Today, you're gonna create a DJ mixer and scratch to mix music, change the speed of a repeating loop, and use sample sounds on a keyboard.

Take a look at this example.

A loop of background music starts playing when the flag is clicked.

The DJ can use meow sound slider to adjust the frequency of the meow sound.


Or press on the space bar to play an additional sound.

In today's club, you're gonna create a DJ mixing tool just like this one and choose the sounds to make your own dance track and even battle with your friends.

Here's another example of a DJ mixer that has a lot more sounds and objects for DJ's to use.

(repeated voice)

To get started, just as you did in the other club days, sign in to Scratch using the information on your CS First Club Pass, then create a new project, delete the scratch cat, and name your program DJ mixer.

And then next change your sprite for your DJ.

Remember help your neighbor if they have a question or ask for help if you need it yourself.

When you're finished with these steps come back to this CS First tab and click on the green arrow to move on to the next screen cast.

(upbeat pop music)


  1. Open the starter project and name it "DJ Mixer."
  2. Delete the Scratch Cat and add a new sprite.
  • "DJ Unkut Demonstrates TRAKTOR Native Scratch Technology | Native Instruments" by Native Instruments ( -- Licensed by Creative Comons Attribution-Share Alike 3.0 Uprorted (
  • "DJ Ravine's Daishocon Setup Day Electro Mix (US Trip Mix)" by DJ Ravine ( -- Licensed by Creative Comons Attribution-Share Alike 3.0 Uprorted (
  • "Juicy M & 4 CDJs - NEW 2014" by Juicy M ( -- Licensed by Creative Comons Attribution-Share Alike 3.0 Uprorted (
  • The song “Festival” is © YouTube-- CC-BY-SA 4.0 does not apply.