Miniature Beeping Circuit Prank

This little device is a fun tool for pranking your friends and coworkers. Every few minutes it emits a brief, high-pitched beep. The beeping gets annoying after awhile, but what is really frustrating is not being able to find it. If you choose a good hiding spot, it can take hours to figure out where it is.

Step 1: Materials

Materials:
Jumper Wires
3 Button cell Batteries (I used LR932 cells but other sizes will work)
Printed Circuit Board (RadioShack #276-159)
3-16V Piezo Buzzer (RadioShack #273-074)
100μF 10V Capacitor
555 Timer IC (RadioShack #276-1723)
1kΩ Resistor
4.7MΩ Resistor
Large Paperclip

Tools:
Soldering Iron
Dremel (optional)


Part Substitutions:
The values of the capacitor and resistors are not critical. You can easily replace them with capacitors and resistors of similar values. The only effect will be that it changes the time between beeps. See Step 2 for a better explanation.

The PCB can also be replaced with any other PCB with enough holes to fit all the components.

Comments

[holidayv]

mine doesn't beep, it clicks. also, it clicks about every 30 seconds. what am I doing wrong?

[person%]

you could stick one inside someone's computer. nobody will even think about opening up their computer or laptop unless they get so pissed that they separate every single object at their workplace.

[White_Wolf]

I need something this small to locate my RC when it flies out of sight. If I were to add a push/pull transistor circuit to this, would it be louder or would I have to use a small speaker? I spent two hours looking for it today in the trees only to find that it must have autopilot. It some how missed all the trees and landed by itself in a cow pasture about two hundred feet away. WHEW! I can't tell in the video just how loud it is.
Thanks
:0)

[DIYHacksAndHowTos]

You could use this project but it would be easier to just hook the buzzer up directly to the battery or to connect it to any extra channels that you might have open. Using a transistor shouldn't affect the volume much, especially if you use a supply voltage above 4.5

[ijudson]

i finished mine and turned it on and it just continued to beep constantly is it because i used a 35v capacitor?

[DIYHacksAndHowTos]

No. As long as the capacitor is rated above 4.5 volts, the capacitor voltage has no effect. Check for any shorts that might be grounding the negative terminal of the buzzer. If you are still having problems, send me a personal message and I will try to help you work it out.

[ijudson]

ok ill try it out thanks a lot

[ijudson]

i did also pay attention to the fix in the schematics and triple checked all the wiring and nothing is is wrong with the wiring

[gamewiz724]

just tried building this but it beeps for a while then stops then beeps again for a long time, any ideal what i did wrong? Also i noticed that on the Assembly pics the speaker + and - go to the same place, pin 3 but in the final pic one goes to pin 3 and the other to pin 4. Which is correct?

[biggy boy]

I have made three of them so far and nun of them work properly. I had the same thing happen with one of mine as you have described. I was reading about the 555 it was stated that the 555 becomes unstable if the cap and resistor values are too high, in the attempt to get long low cycles IE 5-10 minute range.
Also you need to watch what 555 chip you are using some of them can not sing as much current as they can source some only will sink 10 ma this i got from off of the data sheet for one of the ones I used.

[DIYHacksAndHowTos]

Sorry. The buzzer should be wired with the positive terminal going to pin 4 and the negative terminal going to pin 3. I will make corrections as soon as I can.

[jrob1212]

hey fellas due to my lack of money i was wondering if these timers would do the job at a cheeper price ?
http://www.westfloridacomponents.com/IC559APE10/NE555N+555+Timer+General+Purpose+Single+Bipolar+Timer+IC+ST+Micro.html

or

http://www.westfloridacomponents.com/IC359/KIA555P+555+Timer+8+Pin+DIP+IC.html

[dan.berry]

Increasing the value of either R1 or C1 will increase the amount of time between beeps. Increasing the value of R2 will increase the length of each beep.

Which values are R1 or R2? C1 is fairly obvious (it's the only capacitor on the circuit, between pins 1,2).

[DIYHacksAndHowTos]

Sorry. I had two different pictures of the schematic and I uploaded the wrong one for the description that I wrote. It should read:

"Increasing the value of either the capacitor or the resistor between pins 7 and 8 will increase the amount of time between beeps. Increasing the value of the resistor between pins 6 and 7 will increase the length of each beep."

I made a correction to the description.

[biggy boy]

I used a 9 volt battery mine buzzes all the time it never shuts off and on just stays on its been on solid for 12 minutes ans still buzzing any idea why?

[DIYHacksAndHowTos]

The problem is that I made a mistake in the wiring schematic. The buzzer should be wired with the positive termined wired to pin 4 and the negative terminal wired to pin 3. That should fix the problem.

[DIYHacksAndHowTos]

I am so sorry everyone. I made two big mistakes in my documentation. In the wiring schematic, the buzzer should be between pin 4 (positive) and pin 3 (negative). This is what is causing problems for some of you. I will post a corrected schematic as soon as I can. Also in step 4 assembly, in the last picture showed both the positive and negative terminals of the buzzer being wired to pin 3. The positive pin should be wired to pin 4. I will post a corrected picture as soon as I can. Sorry about the confusion and the slow response.

[krich]

I built one of these, but added a photocell so that it would only chirp in the dark. Much harder to find!!

[BlackDidThis]

Now THAT is mean!
Especially if you put it somewhere around the bedroom where the victim goes crazy to its beep and can't sleep from it... imagine it shutting up every time you open the lights to search for the annoyance!

Did you just add it serial after the battery?

[radioman673]

so what would be fun is to put an optical device on it where it would "shut off" when some one got close to it =)

[Mythbuster009]

That would also drain the battery much quicker, but it would also prolong the fun :D

[The Lightning Stalker]

Does the solder stick to the paper clip very well? Solder doesn't usually stick to steel.

[gamewiz724]

Surprisingly yes.

[mikeasaurus]

I hate love these things!