The Annoy – A Tiny Intelligent Buzzer using PIC10F202

A Tiny Intelligent Buzzer

A while back I made a blog post about a PIC10F200 Project: The Annoy. In this project they combined the simplicity in design along with the creativeness that I always look for, into a project with no real use other than for fun. However, the project seemed a little too large and we felt we could improve upon it, so let’s get to it!
In this article we will take a look at the original, ‘The Annoy’ project, and see what we can do to improve it. Specifically, we’ll make a PCB for the project, find the smallest PIC package available for it and make a nice enclosure for it. Additionally, we’ll switch over and use microchip’s new XC8 compiler so we don’t have to use assembly for programming.

A Tiny Intelligent Buzzer

The goal of this project is to build something that is annoying and borderline tortuous. To do that we will use a microcontroller and a speaker to generate some chirping and buzz-like noises every few minutes in order to slowly drive people nearby insane.
To build this project, we will use a 10F202 PIC microcontroller. It will output some sounds to a speaker to create the chirping noises and then use internal pauses to wait a few minutes before outputting the next chirp or buzz. To conceal the project, we’ll make a small black enclosure and add an on/off switch.


PIC 10F202 (SOT23 package)
PICKit Programmer
1uF Ceramic Capacitor
0.47uF Tantalum Capacitor
CR2032 Battery Holder
CR2032 Battery
Copper Clad PC Board
Ferric Chloride Etchant
LaserJet Printer
Glossy Paper
Soldering Iron
Clothing Iron Iron


Parts List Details
Luckily this project is more software based than hardware so there’s not many components. The more important components are described in more detail below.

PIC 10F202 (SOT23 package)
This is the microcontroller that we’re going to use to generate the bzzz or chirp noises through the speaker. It’s a super tiny SOT23 6 pin package so it will barely be visible once soldered into the circuit.

PICKit Programmer
To put the program onto the PIC, we’re going to need a programmer. To do that job I’ve chosen to use a microchip PICKit programmer. It will load the .hex file onto the PIC10F202.

Copper Clad PC Board
For this project we’re going to be making our own PCB so we’ll need some copper clad PC board. We’ll use etchant to eat away the extra copper after transferring toner from some glossy paper to get our circuit design onto this board.

We don’t need a fancy speaker here, just something small that does the job. The smaller the better, but we’ll still want it to be loud, so make sure its a decent quality speaker. You could also use a buzzer, but then the sound would always remain the same tone & pitch.

Schematic Overview
The schematic shown below is just as simple as it seems to be. This project is based upon the premise of using as little parts as possible to be as annoying as possible 🙂 so its kept super duper simple!

 Tiny Intelligent Buzzer schematic

Schematic Specifics

The main processor for this board is the PIC10F202 which is a tiny microcontroller in a SOT-23 package with 6 pins (it’s not labeled on the schematic–doh!, but I think its obvious which 6 pin part we’re talking about). Although we’re only actually using 3 of the pins: power, ground and output to the speaker.

Two capacitors are used in this design. The first capacitors is across the power and ground connections to make sure the PIC has enough current to operate nominally. The second capacitors appears before the speaker. This will increase the volume of the speaker a little bit.

The speaker that we’ll use is a generic ear-bud style speaker that we’ve cut off of a set of headphones. The PIC can’t output too much current so don’t expect it to drive an 8Ω speaker and be really loud, use some small ear-bud speakers like we did.

PCB Artwork
The PCB layout for this project is really simple. Most of the copper is used for a ground plane and a power plane. The smaller spots are all pads for the capacitors, battery, microcontroller and speaker.

Pads vs. Thru-Holes
When you print it out you won’t be able to tell the difference however. In the board layout tool (seen in the picture above) the green circles represent where the thru-hole parts will go and the surface mount parts are just square red pars, part of the rest of the copper on the board.

Read more: The Annoy – A Tiny Intelligent Buzzer using PIC10F202

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