Wednesday, April 12, 2017

Computa Pranksta USB Mouse & Keyboard Device User Manual


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Computa Pranksta now available on Amazon
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Computa Pranksta User Manual
For Device Version: v0.90.0 or later
By Gabriel Staples
Written: 12 Apr 2017
Last Updated: 17 July 2017
Update History (newest on TOP):
-20170717 - added YouTube video: "How to Use & Configure..."
-20170423 - bug section updated w/some info about Caps Lock Response Mode 10
-20170422 - now available for sale on Amazon! Purchase links added.
-20170421 - added images
-20170416 - added bug notes; minor additions
-20170412 - initial version

Congratulations on your purchase of the Computa Pranksta USB Mouse and Keyboard device. Don't have one yet? Click the link above to purchase it on Amazon. This device is great for playing tricks on your friends, or just for keeping your computer awake when giving presentations, watching movies, playing certain video games (like Real Flight RC simulator) or when you don't have admin rights to change screensaver and screen lock settings.

This devices does NOT require any software or special drivers on your PC. It simply tells the computer it is a standard Human Interface Device mouse and keyboard. If your computer tries to detect a new device and install a driver, don't worry about it--even if it says it "fails." The device will work anyway.

Video: How to Use & Configure the Computa Pranksta USB Keyboard & Mouse Prank Device

Computa Pranksta facts:
  • It does NOT require any special software on your computer.
  • It does NOT install anything on your computer.
  • It doesn't harm your computer.
  • It DOES type on your computer just like a human would be able to type on a keyboard.
  • It DOES move and control your mouse on your computer just like a human would be able to move the mouse physically around to control the cursor.
  • The computer thinks it's a USB keyboard and mouse.
  • To see all that the Computa Pranksta can do jump straight down and read the text in blue for all of its various modes and functions.
  • It has 93312 unique user configurations.
  • It may take up to 10~15 sec or so to begin working once you plug the Computa Pranksta into a USB port.
  • If it doesn't seem to work in one of your USB ports, keep trying until you've tried *all* the ports, as not all ports are exactly the same. As a last resort, plug the device into a USB 2.0 hub and then plug the hub into the computer.
  • It has been tested and works in Windows.
  • It has not been tested in Mac OS, in Linux, or on Chromebooks. No guarantees it will work on these operating systems, but you can always try.


Computa Pranksta Images 
(click to enlarge)

What it does:
The Computa Pranksta can type on your computer and move your mouse. It's essentially a "smart" USB mouse and keyboard with special functions, keystrokes, and movements pre-programmed in. Due to the nature of how USB keyboards work, however, it also has the unique feature of being able to *read* Caps Lock, Num Lock, and Scroll Lock key presses you make on your actual keyboard. This is important, as this is how you will interact with the device to change its configuration settings.

It has a total of 8 x 9 x 12 x 9 x 12 = 93,312 user configuration permutations, or unique user configurations. Have fun. Try them all. :)

Just reading to see what this thing can do?

What to do when the Computa Pranksta first arrives:
  • Plug it in to any USB port (preferably a USB 2.0 port). It may not work in some USB 3.0 ports. You can identify USB 3.0 ports because they are marked SS ("Super Speed"), or have a blue plug. If you only have USB 3.0 ports, try each port. If the Computa Pranksta doesn't work in any USB 3.0 ports, plug a USB 2.0 hub in then plug the device into the hub.
  • It may take up to 10~15 sec or so to begin working once you plug the Computa Pranksta into a USB port.
  • When you first receive it and plug it in:
    • It will slowly drag your mouse to the lower-left corner of the screen.
    • It will randomly type a random number (1-10 characters) of random characters every 0 to 10 seconds. To see the characters type out, ensure you have a text editor open (Microsoft Word, Notepad, email, LibreOffice Writer, etc...)
      • Here's an example of the text output after several seconds: Nb{Ef>{&H%BVSV'l,K",Pa{@U>2AUGG=$^YD{g?U_[kL6ratTB >$DvRcv$
  • Press Caps Lock to cycle through 11 unique mouse movement modes plus the mouse OFF mode, for a total of 12 Mouse Move modes.
  • CAUTION: It doesn't have a protective case (sorry, maybe in a future version), so I recommend you wrap up the bare circuitry part of the device (except the plug part of it of course) in electrical tape or masking tape or something, to protect it from static electricity/Electro-Static Discharge (ESD). This is especially important in dry climates, where static electricity is worse. You might consider putting it in the silver ESD-safe bag it first came in to keep it safe during transport and when not in use.
CAUTION: Do NOT try and reprogram the Computa Pranksta from source code or else you will permanently lose its functionality and have to buy another one to get its functionality back.

To reconfigure the device's settings, you will use a unique sequence of Scroll Lock and Caps Lock key presses, as described below. 
  • If you think your keyboard doesn't have Scroll Lock or Caps Lock, look for the smaller font on your keys (usually blue in color) associated with the "FN" Function key. You may have to hold the FN key while pressing INS, for instance, to get Scroll Lock. Google your particular laptop or keyboard for help. A special key sequence may be required. 
  • For Chromebooks, for example, a quick Google search tells me that alt + search is used for Caps Lock. For Scroll Lock, you may be able to use an "On-Screen Keyboard" to access a virtual Scroll Lock button, or just plug in an external keyboard with built-in Scroll Lock.
  • Use an external keyboard to get Caps Lock and Scroll Lock if you have no other choice. Remember, the device will still function without you being able to press these keys--it's just that you need these keys to reconfigure the settings. Again, pressing these keys is only required to reconfigure the Computa Pranksta, not for it to work normally.

How to Enter "Programming Mode" (Scroll Lock x 5):

To enter programming mode, open up any text editor (ex: Microsoft Word, Notepad, LibreOffice Writer, etc, but NOT Notepad++, as its autocomplete feature messes up the typed output from the device). With your cursor in the editor, plug in the Computa Pranksta. Once it is active, press Scroll Lock 5 times quickly. If you wait too long between presses (~ 1 sec) it will time out and you'll have to do the 5 presses again. The device will type out the following into your text editor you have open:

Computa Pranksta v0.90.0, by Gabriel Staples,
keyboardMode = 2
timingModeKeyboard = 3
mouseMode = 3
timingModeMouse = 0
capsMode = 1

Notice that upon entering programming mode it prints (types out) its name, its version number, and the author and website, followed by the 5 different mode settings and which mode number they are set to. Each of these 5 settings is described in detail in the blue text below. 

To save your settings and exit programming mode:

Press the Scroll Lock 5 times (SCROLL X 5) quickly again. If you do NOT press this sequence again to save your settings, they will remain only until the device is unplugged. Once the device is unplugged and plugged back in, it will revert to its previously-saved settings.


How to reset all settings to default:

In programming mode, reset all modes to default by pressing Scroll Lock 10 times in a row (SCROLL X 10). Again, this only works while in programming mode.
Important: Doing this does NOT update the values saved on the device. To keep the values from being reset to what they were when you cycle power you must still do Scroll x 5 to save and exit.

Changing Keyboard, Mouse, and Caps Lock Response Modes:

User Configuration Key Presses Quick Reference:
To enter/exit programming mode: SCROLL X 5

While in programming mode: 

SCROLL X 1 = Change Keyboard Typing Mode
SCROLL X 2 = Change Keyboard Timing Mode
SCROLL X 3 = Print all current mode settings
SCROLL X 10 = Reset all modes to defaults
CAPS X 1 = Change Mouse Move Mode
CAPS X 2 = Change Mouse Timing Mode
CAPS X 3 = Change Caps Lock Response Mode

SCROLL is Scroll Lock
CAPS is Caps Lock
"KEY X n" (ex: "CAPS X 3") means "quickly press the specified key 'n' number of times in a row to perform this action"

Keyboard Typing Modes (SCROLL X 1):
-performed randomly according to the Keyboard Timing Mode interval setting below
-while in programming mode, press Scroll Lock one time to cycle through these modes

0. OFF
1. randomly type a single random character
2. randomly type a random number (1-10 characters) of random characters (DEFAULT)
3. randomly type "hello"
4. randomly type “G”
5. randomly press (ie: toggle) the Caps Lock key; note: this will also trigger the CapsLock Response Mode set below—including cycling through the Mouse Move Modes if that’s what you choose to do, for example.*
6. randomly scroll up a random distance (1-10 mouse scroll wheel “clicks”) on the screen (makes it hard to read their emails or websites)
7. randomly put the computer to sleep (you mean prankster you!) (§)

*However, if the CapsLock Response Mode is set to sleep, the Keyboard Typing Mode will NOT press Caps Lock, as this effect can be achieved instead simply by setting the Keyboard Typing Mode to sleep.

(§). NOTE: if the keyboard “put computer to sleep” mode is selected, for your protection (so that you don’t get locked out from being able to reprogram the device) Keyboard Timing Mode CANNOT be set to modes 0 through 3, inclusive. In other words, the device will automatically set the Keyboard Timing Mode to mode 4 if you try to set it to 0, 1, 2, or 3.

Keyboard Timing Modes (SCROLL X 2):
-controls how often the “Keyboard Typing Mode” action occurs
-while in programming mode, press Scroll Lock two times to cycle through these modes

0. randomly every 0 to 0.1 sec (§)
1. randomly every 0 to 0.2 sec (§)
2. randomly every 0 to 2 sec (§)
3. randomly every 0 to 10 sec (§) (DEFAULT)
4. randomly every 10 to 30 sec
5. randomly every 30 to 60 sec 
6. randomly every 1 to 5 min
7. randomly every 5 to 15 min
8. randomly every 15 min to 1 hr

Print (type out) all current mode settings (SCROLL X 3):
-while in programming mode, press Scroll Lock three times to print (type out) all current mode settings.
Here is an example of the output:

keyboardMode = 2
timingModeKeyboard = 3
mouseMode = 3
timingModeMouse = 0
capsMode = 1

Mouse Move Modes (CAPS X 1)
-performed according to the Mouse Timing Mode interval setting below 
-this is the only mode that will actually remain active during programming mode, this way you can see its effect immediately while in programming mode
-while in programming mode, press Caps Lock one time to cycle through these modes

0. OFF 
1. randomMouseJumpAround
2. randomMouseBuzzAround
3. dragMouseToLowerLeft (DEFAULT)
4. multiCursor 2
5. multiCursor 3
6. multiCursor 4
7. multiCursor 5
8. mouseCircle
9. mouseSquare
10. mouseHeart
11. mouseStar

Mouse Timing Modes (CAPS X 2)
-controls how often the “Mouse Move Mode” action occurs
-while in programming mode, press Caps Lock two times to cycle through these modes

0. continuously move (DEFAULT)
1. randomly every 0 to 0.2 sec
2. randomly every 0 to 2 sec
3. randomly every 0 to 10 sec
4. randomly every 10 to 30 sec
5. randomly every 30 to 60 sec
6. randomly every 1 to 5 min
7. randomly every 5 to 15 min
8. randomly every 15 min to 1 hr

Caps Lock Response Modes (CAPS X 3)
-performed every time the Caps Lock key is pressed (or as described below) and if the Computa Pranksta is plugged in
-while in programming mode, press Caps Lock three times to cycle through these modes

0. OFF
1. cycle through all Mouse Move Modes (DEFAULT)
2. cycle only through “MultiCursor” Mouse Move Modes (1 through 5 cursors)
3. cycle through the Keyboard Typing Modes (do the next Keyboard Typing Mode action once right now, but also keep it on to randomly occur at the given Keyboard Timing Mode interval)
4. allow the currently set Mouse Move Mode to function only when CapsLock is ON (this mode is good to keep your computer awake while doing professional presentations, for example; just turn the Keyboard Typing Mode OFF, and now use Caps Lock to turn mouse movement on and off)
5. allow the currently set Mouse Move Mode to function only when CapsLock is OFF (this one is pretty good/quite irritating whenever you’re typing, because if you want to type in lowercase you have to turn CapsLock OFF, which means the mouse movement is ON, so you can’t click around in the document properly to edit it. This means you have to constantly press CapsLock to either type properly or click properly, but you can’t do both at once. :))
6. type a single random character
7. type a random number (1-10 characters) of random characters
8. type “hello”
9. type a “G”
10. keep CapsLock on; every time the user turns CapsLock OFF, the Computa Pranksta will say (figuratively—it doesn’t actually type this), “no way, not on my watch!” and turn that CapsLock right back ON within 15 seconds; great prank on people trying to type, as every 15 sec or less while typing they’ll have to hit the Caps Lock key again to turn it back off (or hold shift) in order to type lower case letters
11. put the computer to sleep (you mean prankster you!); here’s a fun prank! Turn on the computer’s Caps Lock, *then* plug in this device in this setting. When the user notices their Caps Lock key is on and goes to turn it off, their computer goes to sleep!

When all done configuring your device, don't forget to press SCROLL X 5 to save and exit programming mode!



  1. None

Known Bugs:
-Bugs are problems or errors with the code and implementation of the code. Ie: these are things I can work on and hopefully fix. If you discover any bugs please report them to me via the comments section below this article or by email (see the "Contact Me" tab at the top of this website to find my email address). Be sure to provide me with your product version number (obtained by pressing SCROLL X 5 to enter programming mode) and approximate date of purchase to help me track down the correct source code to debug.
  1. In firmware v0.90.0, Caps Lock Response Mode 10 ("keep CapsLock on"), doesn't behave exactly as originally intended. Instead of ensuring the Caps Lock key is on every 15 seconds, it does the following. For the first 256 seconds or so, it works as expected, ensuring Caps Lock is on (or turning it on) every 15 seconds. After 256 seconds, however, due to an implicit promotion of bytes to signed integers when used in mathematical operations, the Caps Lock is simply forced to remain on, or rapidly pulsed on and off continually. Since this errant behavior is still an excellent prank, however, there's no reason to despair. :) Just use it as-is! For firmware versions v0.93.0 and on (this is the 2nd released version), however, the bug is fixed and the Caps Lock will be triggered to ON only every 15 seconds when in this mode, as originally intended.

Known Issues:
-Issues are outcomes which are normal due to the nature of the product, but about which the customer should be informed in order to work through them. They are different from bugs in that they are not problems or errors with my source code that I have direct control over fixing.

  1. “Jammed” key; ie: the actual physical keyboard won’t respond after I unplugged the device while it was in the middle of typing something out 
    1. Problem: If you unplug the device in the moment it is typing a character on the keyboard, it may “jam” a virtual key on the keyboard, and your actual keyboard on the computer may temporarily not respond properly (until you do the below fix). Ex: pressing “ctrl + A” to select everything in the text document you are working on may not respond anymore. I say “virtual” key because no physical key on your keyboard is actually jammed. The way that this device types capital letters is by pressing a “shift” modifier key in conjunction with a key code. It is possible that your computer got caught up somewhere during this transmission, since you unplugged the device in the middle of the transmission. 
    2. Solution
      1. Unjam the virtual modifier key by pressing the Caps Lock and Shift keys a couple times each on your keyboard.  If that doesn’t solve the problem, you need to press every key on your keyboard until you press the “jammed” one to resend a clean signal from the keyboard to your PC. The easiest way to do this is to first “Lock” your screen (see below for how to do this) and then gently press the base or side of your hand down on as many keys as you can at once, and drag your hand back and forth across the keyboard until you’ve pressed all the keys. I say to do it this way simply so you can press them all quickly and not waste your time pressing them one at a time to find the jammed key.
      2. To “Lock” your screen:
        1. Windows 7: click the Start Menu, then the little arrow next to the power options, and choose “Lock”
        2. Windows 8: click the Start Screen button, then click your little name and picture in the top-right of the screen, and go to “Lock”
        3. You can also try the shortcut: Windows Key + L, but this probably won’t work if you have a jammed virtual key.
      3. If the above doesn’t work, just restart your PC. However, let me note: I’ve never had to do this to fix the jammed key problem. Pressing Caps Lock, Shift, or all the keys on the keyboard has always worked for me.
  2. Device doesn’t work in USB 3.0 ports. Note that you can identify USB 3.0 ports on a computer because they are oftentimes marked with either a blue plastic center, or they say “SS” or “Super Speed” or something along those lines next to the port.
    1. Problem: This device is a USB 1.1 compliant low-speed device. Sometimes, for whatever reason, these just don’t work well in modern USB 3.0 ports.
    2. Solution: Plug this device into a USB 2.0 port or into a USB 2.0 hub which is plugged into a USB 3.0 or 2.0 port. 
  3. Device doesn’t work after computer wakes up from sleep (assuming it is what put the computer to sleep, for instance)
    1. Problem: After the device puts a computer back to sleep, sadly (maybe I can find a work-around for this in a future version), it doesn’t properly reconnect to the computer. This means it won’t continue running from where it left off. 
    2. Solution: Turn the computer back on (ie: wake it from sleep if you haven't yet), then unplug the device and plug it back in to get it talking to the computer properly again


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  1. It works!
    I did have some trouble with USB ports, but I found a port that worked. We have a policy that our work computer automatically logs us out after 15 minutes of non-use. Software "mouse-jigglers" are not allowed. This keeps the mouse moving without the need for any input or software.


    1. Hi, what settings in the device have you seen to be the most desirable for this application? (I imagine you've changed them a bit?)

  2. Well, it worked for one day and then poof, no good. Now all it does is give me the "USB device not recognized" error and nothing happens.

    1. That's too bad. Have you tried it in another computer? In all the computer's ports? In a USB 2.0 hub? Does the computer show the little icon in the bottom right indicating it's trying to install a driver after you plug it in? I've found in some computers it *does* need to complete that driver installation for it to work, and that automatic driver installation can take up to 5+ minutes.

      I wonder if you've shocked it accidentally and killed it. Have you been carrying it around outside of the static bag it came in? Ex: bouncing around in a backpack? Is the humidity in your area super low (this increases the probability of electrostatic buildup and shocking it)?

      I recommend you put electrical tape around the device to protect it.

      Try all of those things and let me know what you find. If you try it in multiple computers and all the ports, and in a USB 2.0 hub, I'll send you a replacement if it still doesn't work.

    2. Also, please ensure you did NOT set the device to do nothing. Perhaps you've turned it off without even realizing it?! Put it in to the last known working computer and USB port, open up a text editor, and press Scroll Lock 5 times to see what the programming settings are. Confirm that it's set in a working mode and not just turned off.


Thanks for your comment or question! If it is a question, I will try to get back to you quickly. Notice to spammers: I personally remove all spam promptly and report spammers to Google, so please don't do it.

Note: some HTML tags are allowed in your comments. To learn how to add bold (<b>...</b>), italics (<i>...</i>), or hyperlinks (<a href="URL">NAME</a>) to your comments, read here.

~Sincerely, Gabriel Staples.

P.S. Yo hablo español también. Je parle français aussi. (I speak Spanish & French too).