"Timed Soundie" or "12 Second Sound Grenade"!

inspired by a combination of throwies, thinkgeek.com's "annoy-a-tron" and my recently discovered love for 555 timers, I've come up with this little guy. i call it the "timed soundie"

once the switch is flipped on the timed soundie, you have 12 seconds before it emits a nice loud and constant beeeeeeeeeeep, enough for me to hear throughout my whole house. on the underside of the soundie is a magnet, becuase throwing them to places people can't reach is fun!

this instructable inspired in part by:
buzzer throwie
the original LED throwie

Step 1: The Nitty-gritty...

parts list:
10uF capacitor
2 3v button cells (cr2032)
1 M ohm resistor
piezo buzzer (about the width around of a 3v button battery)
555 timer
electrical tape

(this is my first time drawing a schematic, so tell me if its wrong!)

the legs of the 555 are bent out and the whole circuit wraps around the buzzer.

all of the parts are soldered or taped directly onto the 555 or the piezo buzzer. the wires soldered onto the circuit going to the batterys are just taped to the top and bottom of a stack of two button cell batterys. like a soundie sandwich, a battery is added and taped to the bottom. (this is optional, incase its just being used as a sound grenade to bother people or for use in an airsoft or paintball scrim)

NOTE: the buzzer's + should be connected to pin 3. the - is connected to pin 1.

Step 2: Throw It!

i've found these little guys do a suprisingly good job at sticking to things. you obviously can't chuck them like you would a throwie, but a nice loft will generally land you a stick. just be sure to flip the switch before you toss it ;-)

(if just being used as a sound grenade, be sure to pad the little guy; he's probably fragile!)

thanks for visiting my first instructable, and please visit my website: lioorg.com



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    76 Discussions

    techno guy

    6 years ago on Introduction

    is there an equation that can give the values of the capacitor and resistor for a given amount of delay, or visa versa

    1 reply
    SquigyXDtechno guy

    Reply 3 years ago on Introduction

    I know this is an old thread and comments, just stumbled across it and had some knowledge to share.

    t = 1.1*R*C seconds

    where R and C are the resistor and capacitor


    if we choose R = 10Kohms and C = 470uF

    t = 1.1*10000*0.00047

    t = 5.17 sec

    found here: https://www.instructables.com/id/555-Timer/


    5 years ago on Introduction

    I have a question I'm new to electronics but would like to know what capacitor is it all I can find is 10uf can you please tell me :) :) :D


    9 years ago on Introduction

     Mod this thing to fit a 9v battery, then throw it behind a big heavy closet.
    Now wait for it to discharge completely !!!

    Nice instructable!

    2 replies

    Reply 9 years ago on Introduction

     or add a CDS cell so everytime someone looks for it with a flashlight , it stops working  LOL


    9 years ago on Step 1

    ok, so my nearby DIY store sells either 4.7 Mohm or 240 Kohm resistors, and no 1Mohm resistors.
    should i just slap a few 240 Kohm resitors behind eachother or should i go for a 4.7Mohm resistor?

    1 reply
    techxperttechno guy

    Reply 7 years ago on Introduction

    when you reconnect it does it go the whole way of just when your reconnecting it try putting a resistor in front and behind the pizzo


    8 years ago on Introduction

    This is a great guide and my first look into 555 timers (and electronics in general). I have a question though, how would you make it go off in 3~ seconds and then turn off after buzzing for 5~ seconds? I plan on using this for a "sound grenade" and use the IntrudAlert Alarm ($1 at local store).

    To make it go off quicker, I would assume you would use a smaller capacitor (maybe 5uF?) but how would you make it stop?


    8 years ago on Introduction

    Anybody know of a good website to buy these parts cheap

    let_it_out_orgtesla coil

    Reply 10 years ago on Step 1

    no, not enough resistance. maybe with a bigger capacitor, but a 1K resistor would make the 555's output go to high immediately


    Reply 9 years ago on Step 1

    No such thing as a MFarad, plus a farad alone is huge, VERY huge