Christmas Present Shake Prank

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Introduction: 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.






Step 1: 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

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

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

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

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

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.

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    40 Comments

    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.

    you could add an acrylic ball and then if they lift it it will shift the weight around

    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.

    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.