Picture of Homemade Annoy-a-thing (Annoy-a-tron)
comparetop.jpg sells a thing called an annoy-a-tron. Its basically a device that, when activated, beeps at a varied interval. While this instructable does not create an exact replica of think geek's annoy-a-tron, if you've got the materials and the know-how, you can make quite a few and deploy an entire fleet of them! :D

(please note that this is not an instructable on soldering or electronic components. prior knowledge is assumed)
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Step 1: PARTS!

Picture of PARTS!
- 20k ohm resistor (red, black, orage)
- 10M ohm resistor (brown, black, blue)
- 10 uF capacitor
- perforated circuit board
- CMOS 555 timer (MUST be cmos / low power consumption to run on a 3v battery!)
- diode
- 3v battery (2032) & battery holder
- asst. lengths of wire
- mosfet (i use a VN10KM, others may work)
- piezo buzzer (apply current and get a beep, just the piezo element itself will not work for this)
- solder
- switch

- soldering iron
- wire cutters
- box cutter or exacto
- knowledge of soldering and electronics :D

Step 2: Nitty-gritty

Picture of nitty-gritty
the circuit diagram is shown below. hopefully it is readable.

if you've got a breadboard, lay one out first and make sure it all works!

AGH sorry! Revised schematic 4/4/09 (thanks dad)

Step 3: On perf board and component leads

Picture of on perf board and component leads
you can find perf board online or at places like radio shack. its really handy, and you can use an exacto or a box cutter to score along the perferation and break off pieces you need.

my project here is 11x9 holes. depending on the size of your components and your layout, your size my vary.

another good idea is to lay out your components before you cut (to know how much you need) as well as after you've cut it. knowing where things go before you start speeds up the process and prevents having to go back.

one last tip: when cutting off excess component leads, you can save them and use them to make connections to the bottom of your board.
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Jan_Henrik11 months ago

haha, very nice!

Derek Vigil3 years ago
What size of diode did you use?
I believe it's a 1N914 Diode.
KG9892 years ago
This may be a stupid question, but in the breadboard photo what are the large red 4 posted components in the top/bottom left corners of the photo?
GASSYPOOTS3 years ago
na the more annoyin one is vuvulza plus fan
glansj5 years ago
I made a boardless version shown below. The first three pics are during construction and the last is the final product. It does not use a mosfet. The wait is about a minute with a half second beep.
Wow, those are some massive resistors.  Aren't  they a half watt and 1 watt, respectively? I was thinking about making a boardless one, but using 1/4 watt or smaller resistors.  Would they be able to handle it?
An smd NE555 chip would work nicely with this.
yah should work
i used 1/8 watt
raykholo5 years ago
any suggestions as to where i might find a cheap piezo as used here?  perhaps chinese store such as dealextreme with free s&h ? :)
I went to Radio Shack and got it for around 5 bucks, I hope this helps.
I appreciate the reply, although the original comment is about 2 years old and I've found some better sources since then.

Save yourself a few bucks if you're planning to make more of these:


I'm just giving you the general pages because these places change their inventory every once in a while and I haven't bought any piezos that recently. I can vouch for goldmine's "3 lead piezo disk" - it's ok quality and you get 3 for a buck. just don't drop it or the wire leads will come flying off.

These places also have good prices on all the other components needed for this instructable. If you only want to make on order, I recommend dipmicro electronics (first link).
WOW thats a great price thanks for the heads up!
cricketm244 years ago
If you skip the mosfet would you connect the wires to each other
Zem5 years ago
Help! D= When I apply voltage to my buzzer, it makes no sound. 
beehard44 Zem4 years ago
you need to give a frequency to the buzzer, not just plain DC
harishere5 years ago
Does this circuit really works with 3v?
the voltage rage for the 555 is 4.5 to 16 volts, so it should
the CMOS version goes down to 2.8V minimum, but if you use the regular one, it might not work
beehard444 years ago
i wanted to make an SMD version of this, but when i contacted my local electronics dealer (wiltron general merchandise), THEY DONT EVEN KNOW WHAT SMD IS!!!1!!!1!!!
i'll just use a few SMD chips sampled and some resistors and capacitors scrapped from old electronics.
Nickel10105 years ago
 Could I change the interval between beeps by making the size of the 10m smaller and making the capacitor bigger?
Just change the value of the capacitor, or you could replace the resistor with a potentometer
Colonel885 years ago
I am going to make one of these and stick it on the ceiling in our Mrs. Blecher's class. She is old and still says Okey-doke :D
put it in the ceiling and she'll never find it XD
raykholo5 years ago
I hate to bring up the transistor debates again, but the 555 can source 200ma of current, without need for the mosfet/transistor.  So the question is whether it is because of the diode and the voltage drop that it produces that the amplification is needed.  I am aware that it is not directly connected to the output pin and piezo but it is still a thought...
ANDY!5 years ago
I made one! it wistles and annoys the heck out of people. I gave it to my friend and it went bezerk  at class!
lmperkins5 years ago
Here is my version. I used a 3volt buzzer and skipped the MOSFET. I also played around with the resistor values to get a long pause and a short beep for maximum annoyance. I think it came out pretty nice. Thanks for the Instructable.

Nickel10105 years ago
The biggest resistor I can find around my house is 1.5m, but if I used a 100uf capacitor would the interval between beeps be about the same? I'm not sure if I'm using the right logic here..
far.peter5 years ago
Can you use a lin comos 555?
Colonel885 years ago
Hmmm... i did this without a MOSfet, just 555, a capacitor, and a resistor and it works just as well.
tommck5 years ago
It would be cool to hear it in action or even better to show some unsuspecting person reacting to it :)
Try you tube you will find there, i have seen it working, people going crazy, lol.
raykholo5 years ago
my finally finished product: using a normal 555 timer (not cmos), an NPN transistor and running off of 6 or 9 volts. Everything is free form built around an 8 DIP socket and the 555 was inserted when finished soldering...
my breadboarded version has the same exact circuit but a different buzzer, and can easily run off of 3 volts. That can work with a radioshack 3v battery clip. After taking the pics, i added 3 more 20k resistors to get a nice longer beep with a total of 80k ohms, and i might change around the 10m to make the intervals smaller.

U think this can work with an LED? if so then i want to use it in a new project of mine.
annoy a tron 6v.JPGannoy a tron 9v.JPGannoy a tron breadboard 3v.JPGannoy a tron alone.JPG
raykholo5 years ago
would a standard pnp transistor work instead of the mosfet?
i read the comments below about this topic, just unclear whether a pnp specifically will work.

im talking about a 2n3906, here it is on wikipedia: link
and u can find datasheets all over google

sorry i meant NPN
That should work well also. You will need a resistor between pin3 of the 555 and the base of your transistor (about 500ohm should work-just a guess).
sounds good i tried breadboarding the circuit today with that transistor, and it didnt work.... so i will try this out tmrw and get back to you thanks
I looked at the circuit again, and I think that you could even get by without the transistor. The 555 can source/sink enough current that the piezo should work directly connected between pin 3 and V+ Let me know!
well i cant get the circuit to work no matter what however, the output voltage is too low from the 555, so a transistor is needed the bigger problem though is the voltage ratings of the piezo buzzers i have tried it with three different ones: they only crackle at 3 volts, yet on 6 or 9 they work great...
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