Instructables
Picture of Christmas Present Shake Prank
We all know someone who shakes their presents to try to figure out what's inside. This project is the perfect thing to give someone who does this. It's a box that plays prerecorded sounds whenever an internal shake sensor is activated.






 
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Step 1: Materials

Picture of Materials
Materials:
  • Cardboard Box
  • RadioShack 9V recording module
  • 9 volt battery
  • 100µF capacitor
  • 2 short pieces of magnet wire
  • Hot glue and hot glue gun

Step 2: Recording Module

Picture of Recording Module
This project is built around the RadioShack 9V Recording Module. It is a basic sound recorder with 20 seconds of memory. It has one button for the record function and one button to start and stop the playback function. For this project, we are making two modifications to the module. We are adding a wire shake sensor to activate the play function in place of the button. Additionally, we are adding a capacitor to temporarily disable the stop function so that the playback isn't interrupted.

Step 3: Make the wire shake sensor

Picture of Make the wire shake sensor
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Start by wrapping the positive lead of the capacitor around the positive terminal of the battery. Be careful not to make contact with the metal casing of the battery. This can create unwanted shorts. Then bend the negative lead of the capacitor into a "J" shape. This will form half of the shake sensor. To form the other half of the shake sensor, remove the any insulation from the ends of a piece of magnet wire and insert it into the negative terminal of the battery. Then attach the battery connector. This will hold the wires in place. Bend the magnet wire into a hook shape and position it as close as possible to the negative lead of the capacitor without making contact. When shaken, these two wires will make contact and activate the play function.


Step 4: Connect the shake sensor to the play pin on the module

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Then, attach this shake sensor to the play pin on the recording module. The play function is activated when the play pin on the module is connected to ground. This is normally accomplished by pressing the play button. In this case, we are using our shake sensor to make the connection. The shake sensor wire is already connected to the negative terminal of the battery. So now all we need to do is attach the other end of the shake sensor (the negative lead of the capacitor) to the play pin on the module. Take the second magnet wire, and remove any insulation from the ends. Insert the one end of the wire into either of the two pin holes indicated in the picture. You don't need to solder the connection. Just loop the wire through the pin hole and twist the wire against itself until it is tight. This should make a sufficient connection. Then twist the other end of the wire around the negative terminal of the capacitor.Shake the sensor to make sure that it activates the play function properly. If not, you probably need to adjust the position of the wires.


Step 5: Glue everything in place

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Once things are working, secure everything to the side of the box with hot glue. Shake the box a few times and adjust the wires so that they make contact when lightly shaken.


Step 6: Record, glue and wrap up

Picture of Record, glue and wrap up
Record the sound effect that you think is most appropriate for your target. It can be a kitten mewing, glass breaking, or a train whistle. Be creative. Then all you have to do is put in the actual present. To prevent the present from bumping into the sensor and messing up the calibration, it helps if you secure it to the bottom of the box with hot glue. If you really want to pull off the illusion of something else being in the box you can also add some weight to match the sound that you picked. Wrap everything up and enjoy the spirit of giving.
roverbeck1 year ago
Thanks for this awesome idea. I made this last year for my kids and they spent the entire holiday season re-recording and re-gifting. As a result I had to wrap the gift in a way that made it easy to open and close again. This allows for easy recording and adjustment of the trigger wires. Also, since this is now a permanent part of our holiday decorations, this year I plan to rebuild it entirely to withstand repeated shaking.
Pfarmkid1 year ago
you could add an acrylic ball and then if they lift it it will shift the weight around
Nicko302 years ago
Thats great. I should add the audio of my mate Cal's reaction to my giant axe prank (see http://youtu.be/c3y4-H2l31Q ) . Then when the cheeky dude shakes his present he will he will hear himself
I just finished mine. but I am having trouble getting the shake sensor to activate right, and to not shut off or repeat too quickly when shaken,
Check out my response to Tinkerer87 for a full explanation. But here is a summary. Adjusting the spacing of the wires will make it more or less sensitive to shaking and Increasing the value of the capacitor will increase the time that the stop function is deactivated.
oh and btw, thanks for this project.
Tinkerer872 years ago
I attempted this, and it appears to work, though I can't seem to get any more then 3 or 4 seconds of playback time when the module supports up to 20.

What am I doing wrong?
I think the problem is that the wires are making contact in the middle of the playback. The start button also acts as the stop button. So if the wires make repeated contact, it's like pressing start and stop repeatedly. I got around this by adding the capacitor to temporarily disable the stop function. But the value of the capacitor that I used (100µF) only gives a window of about 3-4 seconds. So if the wires touch after that, then it will stop the playback. If you use a higher value capacitor it will give you a bigger window. Also, you might arrange the wires a little further apart so that they don't touch when it isn't being shaken. Let me know if that doesn't fix your problem. Thanks and good luck.
Ok, last post to my original. It appears sometimes it plays all the way through and others it stops randomly. I don't see a short anywhere in the wiring that would cause this to happen.
Ok, just let it sit and tried it again and it played longer, but not the full clip I recorded.

PS - I tried using a single piece of ethernet cable but it's not flexible enough. It does work well enough to connect the capacitor to the board.
brandegor2 years ago
how the heck do people figure this stuff out? I love it!
ceknight2 years ago
LOL... so cool! Love the Meow! Meow! at the end. But you better have a REAL good present in there to make up for the kid tearing that box open and NOT finding a kitten in there.
static ceknight2 years ago
Then again the thinking person would pull this exact prank on a child.
diyer12342 years ago
a gunshot sound would be great
-A-N-D-Y-2 years ago
Great instructable, I've been involved with electronics for 20+ years and never heard insulated (enameled) wire referred to as magnet wire! so you learn something new everyday :) I was thinking you need some magnetised wire!? then looking at your instructions I could not figure it out until a google revealed:

http://en.wikipedia.org/wiki/Magnet_wire

So you can learn something new everyday :)
Yeah, it doesn't even really need to be magnet wire. It just needs to be thin enough to fit through the pin whole and flexible enough to move when shaken.
Solid core telephone wire works great for project wire.
It's called magnet wire for the simple reason that it's used to make the coils that form electro-magnets,

If you move a wire through a magnetic field (or the reverse) you generate a current in the wire. This principal used with electro-magnets is used as the basis for motors, generators, alternators, transformers, etc.

- You probably already knew this from the wiki, but I thought I'd clarify it for anyone else who hadn't read it and didn't feel like looking it up.
(I haven't actually read the wiki, but I would expect it would have had this information in an expanded and better written form)
hyperr2 years ago
I am doing this when I get home from school, only instead of recording me making the sound i have cut the microphone off of mine, and replaced it with an aux cable end(headphones) so I plug it into my headphones jack on computer, play real sound hold my record button and presto! Real sounding cat noises!!
fredellarby2 years ago
Before the electronic age, my mother was a dedicated present shaker.
One year I put a piece of glass and a heavy nut in side a smaller box inside the present. First shake - the sound of glass breaking. Oops!
Next package included a jar of thick motor oil and a weight inside the jar. Tip it and you're rewarded with a slow thunk. Tip it back, the same. Drove her nuts.
detnyre2 years ago
How many volts is the 100uf capacitor? Radio shack has one that is: 100µF 35V 20% Radial-lead Electrolytic Capacitor but 50v seems a bit much?

Please advise.
DIY Hacks and How Tos (author)  detnyre2 years ago
It doesn't really matter as long as it is rated for more than the supply voltage (9 Volts in this case). It also doesn't need to be exactly 100µF. That is just what I used. It disables the stop function for about 3 seconds. If you use a smaller value the it will just disable the stop function for a shorter time. Or if you use a larger value it will disable it for a longer time. Its really flexible. So just whatever you can get a hold of the cheapest and easiest. And when you are done with the project, you can disable the whole thing and keep the parts.
I'm not the most experienced person with electronics, but I would say that the capacitor voltage rating just needs to be larger than the voltage applied to it (in this case around 9volts). The 35volt capacitor should be good for this project!
cheesehead2 years ago
really great job modding this! i love doing simple fun stuff like this!
kintekobo2 years ago
Ahhh. Now to record the sound of breaking glass!
Brilliant! I need to try this with the kids!
Ten Thumbs2 years ago
That kitten mew would be infinitely more funny if combined with one of those weasel balls that move randomly, to go off at the same time for a second or two.
PGrevie2 years ago
I've thought about making a "low-tech" version of this concept. I want to line a box with aluminum foil and fill it with snap caps (granules wrapped in tissue paper that pop when you throw them on the ground) and small pebbles. The rocks will help the snaps go off and the foil will protect the cardboard from any sparks.
The ideal sound would be breaking glass or a whimpering puppy.
Dakotamouse2 years ago
I've never made an electronic gizmo but this is so well explained I am really tempted to try it!
sitearm2 years ago
@DIYHacksAndHowTos; I like recorded mews at the end of the video. Schrödinger's Kitten? Cheers! Site
Now I need to find an instructable to make the present wiggle a little on its own from time to time like there is something inside it moving.
Or you could just pull a vibrator out of an old cell phone. Some of them are pretty strong. My mum's old Nokia actually moves around.
Get a servo and attach it to a weight of some sort. You could make it remote controlled so you can do it whenever.
Good idea. I did find that radio shack sells a 3 volt vibration motor for about $4
That is really funny! Is there a video of it?
Unfortunately, there is only a video of the build. I don't have any footage of it in action. I wanted to get the instructable posted before Christmas so that other people could try it. But I will post one as soon as I get a chance to try it out.
I look forward to it, but I'm glad you posted it before Christmas. It is awesome!
So doing this to my nephew :-D
mikeasaurus2 years ago
Haha, great idea!