Sonic Grenade From Mostly Scavenged Parts

About: Electrical Engineering Student

After seeing a sonic grenade on somewheres on the internet, I wanted to make my own, but living in a small town meant that I would be forced to either order parts and wait for them to come in, or just use what I had on hand. I chose the latter, which ment that I could build it right away, but that it would be somewhat crappier than the one I had seen.

The two things I wanted it to do are
1-Have a pull switch, like a grenade would
2-Provide a small delay between the pulling of the pin and the first noises it made

This is my first instructable, so I welcome any feedback you may have.

Step 1: Get Some Parts Together

Most of the parts that I used came from things that were destined for the trash. The only thing that I ended up buying was the actual noise maker ( thinking that I would not be able to get one, I had originally made my own out of other scavenged bits, but its the noise it made wasn't the greatest). The noise maker is one of those magnetic window alarms. It cost me three dollars for two of them.

You also need a container to put it in, bits of wire, bits of metal, solder, soldering iron, a spring, a tiny push button switch (mine came from a VCR) and other misc garbage type trash.

Step 2: Do Up the Lid

The easiest thing to start with is the lid. Some holes need to be drilled for this part, and some metal cut.

Out of your misc trash, find something non-conducting and round to use as the pull-pin. (I used a chunk of plastic from the broke VCR, it tapers out a bit making it perfect, won't fall through the hole). Drill an appropriately sized hole in the centre of the lid for it.

On the underside, on either side of the hole, attach pieces of scrap metal. I had originally tried gluing them down, but it didn't work so well, so I drilled holes and used tiny nuts and bolts that I had also scavenged.

Also, I drilled holes for the small reset button, and an optional LED indicator light that tells you when the pin is pulled and the thing is working.

To do the actual pin switch part of the lid will take some trial and error. I used a spring that had a low stiffness and attached it between the metal parts so that it reached across them when the pin was out, and was pressed away when the pin was in.

At this point I soldered wires to all of the things that I had attached to the lid. Be sure to choose an appropriate length of wire.

Step 3: Doing the Delay Circuit Bit

Easily the most annoying step.

If you have a bread board, I recommend doing up the circuit on that first to test out the length of the delay, and how the alarm sounds when it turns on. The values you end up using for the components will most likely vary depending on what kind of transistors and alarm and all of that you use.

A couple of notes about this circuit -
-Because of the components I had, it isn't very grenade like in the fact that it there is no sound from the buzzer for a few seconds, and then it slowy turns on
-The reset button is there because after pulling the pin the first time and having the buzzer sound, the capacitor needs to be discharged to have the delay the second time. On its own, this takes forever.
-I used regular AA batteries, the alarm came withs its own button cells, totaling to more than 3 volts, but I took them out to use in something else. Do what you please here (as with the whole thing).
-My components are mounted on a piece of a soda pop box, again due to the fact that I didn't want to order any of that circuit board stuff and I didn't have any on hand. The components are attached using the wire wrap techniques with a little bit of soldering at the connections to make sure things didn't shake loose.

Step 4: Attach the Batteries, Alarm, LED, and Switches to the Board.

Pretty self explanitory here.

For the alarm, I just left it all in the case and put the alarm out to where the batteries used to be in the alarm. At this point, I took some things out of the alarm that it wasn't going to need to be used for this for use in something else (switches).

Make sure the positive and negatives are going to the right places. This shouldn't be hard to figure out.

Step 5: Finish Up

Test it out a couple of times before putting the lid back on. Be careful when twisting the lid back on, I had some connections come undone on me the first time.

You can also cut out parts of the container to allow the sound out of it better, or attach the pieces a bit better inside so it can be thrown or suchlike. I wasn't to worried about this part as I have been mainly using it to go off when doors are opened.

Kinda of a trivial toy when finished, but I find it entertaining.



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    37 Discussions


    12 years ago

    Very nice , certainly for your first tutorial , Wouldn't it be beter to use a green led ?

    2 replies

    Reply 12 years ago

    Using scavaged parts, didn't have a green led.

    im making one with a green led, larger cap (470), Tylenol container (looks like a grenade) and a piezo buzzer from radioshack and im spray painting it black :)

    then you know if you accidentally drop the pin =)
    also it just generally makes it look way more thoopar hardcore


    Reply 11 years ago on Introduction

    An LED can come in handy at night time if you throw it and you don't know where it is. you can just look for the light.


    10 years ago on Introduction

    can someone make one that is a sphere and instead of pulling a pin you press a button? plz i am not very good makeing stuff up.

    1 reply

    Reply 9 years ago on Introduction

    definately, instead of attaching that spring and that metal peice attach a toggle switch and solder the leads through that =)


    Reply 10 years ago on Step 1

    It was quite a while ago now, but I believe that it was either at a local dollar store, or a Canadian Tire.


    10 years ago on Introduction

    Dude, the container is clear and wwwwwaaaaaaayyyyyyyyyyyyy too big. Get like one of those new gum containers or some thing.


    10 years ago on Introduction

    pbkid1 i am unable to find your 1000 times better !!!!!!!!!!!!!!!!! please direct me into the right direction so i can go directly to your better unit.i will get back to you directly when i see the schematics.


    10 years ago on Introduction

    then let's see u work ur butt off then have some jerk (namely you) put you down!

    Mr. Deeds

    10 years ago on Introduction

    You know what, you suck!!!!!!!!!!!!!!!!!!!!!!!!! And you use way too many many exclamation points!!!!!!!!!!!!!!!!!!!! Instead of bringing people down, why don't you give advice for a change!!!!!!!!!!!!!!!!!!!!!!!


    heres what you do, get a tenis ball and drill a hole big enought to fit a peice of 1/2 in id of pvc it should stick out of the tenis ball about an inch and put what electricj made in side and paint black. wala!


    10 years ago on Introduction

    Dude, come on. Least you could do is constructive critcizm.