Introduction: Use Spells to Control Your Computer!

Ever wanted to use spells like Harry Potter? With a little work, and some voice recognition, this can be mastered.

Things you need for this project:
  • A computer with Windows XP or Vista
  • A microphone
  • Some time and patience!

If you enjoyed this Instructable, hit me up with a plus! Thanks. :D

Featured on Gizmodo.

Step 1: Download Voice Activiation Command Software

I simply googled the term, and Voice Activated Commands came up as the first choice. This program serves a useful purpose in RPGs and other computer games where voice commands can be given rather than typing in key combos. For this project, it can be used to cast "spells" on your computer to manipulate it to do your bidding.

VAC Download Page

It's currently only available for Windows XP and Vista.

Step 2: Grab Some Spells and Plug 'em In!

For researching all of those tip-of-the-tongue-can't-quite-remember spells, the coolest place I found was MuggleNet. It's the cream of the crop as Harry Potter fan sites go. Their spells section is extensive and gives a description of each spell.

Some sample spells:
  • Brighten Screen
  • Dim Screen
Petrificus Totalus
  • Hibernate
  • Mute
  • Volume Up
  • Stop In Web Browser
  • Exit application

Also, I made an action called "Marauder's Map" which is activated by saying "I solemnly swear I am up to no good." which opens the browser to the home page.

Step 3: Enter the Incantations

Boot up VACBuilder and create a new profile. Name it whatever you like: I did Harry Potter as an example.

Next, you want to start making spells. You go into the "Action Description" box and hit the "Add" button. Enter the spell name and click "OK".

After this, go over to the "Command List" box. This is where you will program what will happen when a certain phrase is said. Qualifier keys can be anything from "Alt" to "Shift", so just explore both lists. The extended keys reach almost anything, including browser commands and media player commands.

If you want to make sure you have the right key, boot up the Keyboard Tester program that came with VAC. Click the button in the top left to change it from "Disabled" to "Enabled". When enabled, your keyboard will light up buttons when you push them.

You can do multiple things with one voice command.. Just add another command and repeat the last step.

The "Command Attributes" can be used for more personal commands, dealing with the duration the combo is held, the pause before it is executed, and the number of times to repeat the combo.

"Profile Activation Keys" deal with activating and deactivating the voice commands by using key combos. I didn't bother with these in my project, but you certainly can if the mood strikes you.

Finally, you want to test your phrase to make sure the computer can recognize the voice commands. To do this, simply hit the "Test Phrase" button in the bottom right corner. If it matches your voice command with the correct spell, you're golden. If it doesn't just try again or pick a different phrase to say.

And of course, save your profile with the button in the bottom right before you close.

Step 4: Categories

If you are going to be using this program for more than one project, you may want to make categories for the different commands. To do this, go into "Tools" and "Category Setup". Hit "Add", make one, and hit "Okay." To add spells to a category, right click them in the "Action Description" box, go into "Category", and click the one you made for it.

Step 5: Boot Up the VAC System

Boot up the VAC system and a little icon with a microphone will pop up.

From the manual:

When the icon is just the microphone:
  • VAC is running and ready.
When there is a blue "P":
  • VAC is running and has a profile loaded.
And when there is a green circle and a blue "P"
  • Vac is running, has a profile loaded and the recognition is active.

To load a profile, right click the icon, go to the top and hit "Load Profile". Then, right click it again and hit "VAC On". Now you're set and ready to go!

I'll get a demonstration video up sometime soon!

My backup file is attached which contains all of the spells I have made thus far. To use them, go into VAC builder and hit "File", "Import", and "Text File (txt)".

Step 6: Your Spells!

Here's what you suggested!

I don't know what he uses, but I'd suggest:Imperio - Task ManagerAvada Kedavra - Shut downOblivio - RestartAlso, he has Volume up and mute, but not volume down. I'd suggest Quietus for that.

Quietus - Reduces VolumeReducto - Closes current windowI solemnly swear that I'm up to no good - Open web browserMischief Managed - Also closes current windowLegilimens - Opens the Task ManagerImperio - Opens the Command Prompt

benthekahn suggests his own reverse psychology spells...

You should make everything a normal but different command. ie...Startup=shutdownmute=full volumeprevious song=next song

Step 7: Additional Software

Here are some other programs you can also use to have some of the same effects on your computers using speech recognition.

  • RedGuff suggests using Shoot, a similar voice recognition program.

Mac OS X
  • Munkey suggests using the default speech recognition software
"speech recognition is built into the Mac OS X system, so you can replicate this exactly without any extra software:"

  • has agreat article detailing how to install and use Perlbox, a voice command program for Linux.
  • CVoiceControl is another program similar to VAC, although the author is no longer supporting the program anymore.


cadibellaw made it! (author)2015-12-30

I LOVE IT!!!!!!!!!!!


natalie 10 made it! (author)2015-09-29

Wow...... It look amazing!

amrodgers12 made it! (author)2015-01-11

What is a free software I could use for this? When I download VAC it tells me I have 14 days.

BubblesGirl915 made it! (author)2014-12-26

Expecto Patronum: your favorite animal appears on the screen! Lol

rjordan-1 made it! (author)2011-03-14

what about win 7

JujubeanO made it! (author)JujubeanO2011-04-27

7 is vista... they are pretty much one in the same

PCfreak made it! (author)PCfreak2012-10-05

No, win 7 is a glorified version of vista

ALogan97 made it! (author)2011-08-30

I used evanesco to minimize the browser instead, since Reducio wouldn't pick up.

ginger20037 made it! (author)2011-07-07

HAHAHAHAHAHA! That's so funny xD I have to try it xD

valariebutternutcake made it! (author)2011-02-23

you should put a list of reccommended spells :)


never mind srry i didnt look through it :)

valariebutternutcake made it! (author)2011-02-23

or you could go on wikipedia

mguyear made it! (author)2011-02-22

The download link in the instructable is linking to an old page. The correct download page is and the newest download file is

The link in the article is when it should be . So when you go to the old page, it is linking to an old install file which is no longer being served on the server.

thepelton made it! (author)2011-02-14

I should think that "Avera Kedavera" would probably cause a system crash. Wouldn't it?

thepelton made it! (author)2010-12-27

What if you used "Stupefy" ?

hedzup456 made it! (author)hedzup4562011-02-13

Stand by

avadra kedavra shut down

Ninja1507 made it! (author)2011-01-15

For those of you disappointed for it not having certain functions. Just write a simple c++ app that does the command you desire. Then have VAC execute the app.

C++ is easy to learn for beginners so if you don't have coding experience don't be scared off by this option. Simple programs such as one to do a basic command could be learned in a matter of hours. Just make sure you start off with the classic "Hello World" :D and you'll be fine.

chandeepa made it! (author)2011-01-06

this software cannot be downloaded

Darkheart069 made it! (author)Darkheart0692011-01-15

google the Softwear there is more than one site if you ..... ya know loook-...
and there is more than one SW that will do this- iits beening used by lots of people i know on steam- so it works and -- its also on sevral sites.- i will NOT link here but google the file name and -- easy..

taywill95 made it! (author)2010-12-05

The VAC builder won't open. It says "Component 'MSINET.Ocx' or one of its dependencies not correctly registered: a file is missing or invalid" I've run the repair on the installer several times and i still get this message.

johndenzell123 made it! (author)2010-09-18

when i start the test, there's an error that said: SAPI falied to initialize. This application may not run correctly. What should I do?

Hwolfw made it! (author)Hwolfw2010-10-17

Go to home then back to downloads

johndenzell123 made it! (author)johndenzell1232010-10-18


mutant made it! (author)2008-06-17

lol... I got one for you. Crucio: Opens AOL. lol

Capt. Kidd made it! (author)Capt. Kidd2009-07-06

I got one, too.
avada kedavra: opens antivirus

JKibs95 made it! (author)JKibs952009-07-14

sectumsempra: your computer starts bleeding profusely... ...No, wait...

tinkerC made it! (author)tinkerC2009-07-14

Turns volume to full, screen brightness to full, load all bookmarks in browser, and plays random song.

JKibs95 made it! (author)JKibs952009-07-14

expelliarmus.... eject disk...

Capt. Kidd made it! (author)Capt. Kidd2009-07-14

stupefy... computer crashes

PCfreak made it! (author)PCfreak2010-06-10

no instead of crashing..........Blue Screen of Death and then a reboot

Capt. Kidd made it! (author)Capt. Kidd2010-06-14

dude, the damn post is almost a year old. don't bring them back.

PCfreak made it! (author)PCfreak2010-10-11

bring what back the blue screen of death????????

Capt. Kidd made it! (author)Capt. Kidd2009-07-14

sectumsempra: big slash appears across computer screen

tinkerC made it! (author)tinkerC2009-07-15

Not as funny as mine, or stupefy. Doesn't quite work, as that keeps the spell. Spells should make the computer do something, not just graphics.

Capt. Kidd made it! (author)Capt. Kidd2009-07-15

your right. sectumsempra makes your computer explode

tinkerC made it! (author)tinkerC2009-07-16

Takes gasoline. Not so good.

Rainb0wTr0ut made it! (author)Rainb0wTr0ut2010-03-04

 Fidelius: Hides current window.

tinkerC made it! (author)tinkerC2009-07-15

No, freezes, then runs again.

PCfreak made it! (author)PCfreak2010-06-10

expelliarmus......Eject CD/DVD Drive

PyroMonger made it! (author)PyroMonger2009-09-12

i like this too but there isnt an option to use it in there?

Landon Sullivan made it! (author)Landon Sullivan2009-07-15

I actually do like that one.

tinkerC made it! (author)tinkerC2009-07-16

Me too. Langlock, Volume mute. Alohamora, auto login.

JKibs95 made it! (author)JKibs952009-07-16

good ones... hmmm... Engorgio: window becomes fullscreen... Legilimens: opens task manager... Lumos: adjust screen brightness...

tinkerC made it! (author)tinkerC2009-07-17

Nice. Can't find more just now.

tinkerC made it! (author)tinkerC2009-07-15


kroq-gar78 made it! (author)kroq-gar782010-08-03

lol booby trap :P

Landon Sullivan made it! (author)Landon Sullivan2009-07-15

XD Way to bash an American product! Japanese manufacturing all the way!

technick29 made it! (author)technick292008-06-17

Hahaha, nice!

tinkerC made it! (author)tinkerC2009-07-15

Thank you.

pgd5000 made it! (author)2010-08-20

I went to the download page and neither link is working, Help please? :)