Classic Siren

Introduction: Classic Siren

About: Rocky is a circuit designer for Electric Dreams Co., Kaohsiung, Taiwan.


This is a breadboard project from the Electric Dreams Kit No 2 that I am providing as a free insight into one of many projects you can build with very little experience or even none in the world of electronics. These particular kits are used in Taiwanese English language classrooms to teach children the basics of Electronics (a big part of the Taiwanese economy) and a fun way for them to learn English. So, if you would like to have a go at building your first electronic project then please read on. Our instructions are very easy to follow with a step by step guide. All you need to do is purchase or salvage the same components as listed within this instructable.

Classic Siren is a project that is a simple audio circuit that uses the frequencies of two 555 timer ICs (Intergrated Circuits) and outputs them through a simple speaker called a Piezo.

To build this circuit you will need the following parts and components:


1 x 1k ohm resistor 1/4W (Brown / Black / Red / Gold)

3 x 10k ohm resistors 1/4W (Brown / Black / Orange / Gold)

1 x 68k ohm resistor 1/4W (Blue / Grey / Orange /Gold)

2 x 555 Timer IC's

2 x 0.10uF 50 volt capacitors (disk shaped ceramic capacitor) will have the number "104" printed on it.

2 x 10 uF 50volt capacitors (Cylinder shaped electrolytic capacitor).

Breadboard jumper wiring:

9 x 0.3" wires (orange)

4 x 0.4" wires (yellow)

2 x 0.5" wires (green)

4 x 0.6" wires (blue)

1 x 0.7" wire (violet)


1 x 400 point 1/2 + size breadboard.

Power Source: 5 - 9volts

1 x Breadboard power supply Module ( Recommended: "Red Wings" 3.3V / 5V Power Supply Module for MB102 Breadboard. Input voltage: 6.5~12V or USB. Output voltage: 3.3V / 5V Max Output current: 750mA (at 6.5V input voltage) 0V / 3.3V / 5V switchable.

1 x USB 2.0 cable (this one pictured is a "Red Wings" which uses a MINI USB 2.0 connector) and power source (PC or USB wall adapter).


1 x 9 volt Battery

1 x 9V battery clip.

1 x 2.0" wire (red) to connect (+) power rails.

1 x 3.0" wire (orange) to connect (-) power rails.

ALL of the above can be bought in Kit form from:


See other projects on display here:

Electric Dreams Youtube Channel

Step 1: Insert Your Two 555 I.C’s

Your breadboard is designed with an alphanumerical grid. This instructable uses those grid co-ordinates to place parts. Be sure you double check your placement of parts, its easy to make a mistake with so many holes close together. Best use a magnifying glass, to make sure your eyes don't deceive you!

Insert your two 555 I.C’s. The 1st 555 place into E5-E8 / F5-F8 and 2nd 555 Timer into E20-24 / F20-24. Make sure the white line on the 555 IC is on the left.

Step 2: Add the Jumper Wires.

Insert (A) Nine orange 0.3 “wires into: J5, Y7 /J20, 21Y / H3, H6 / G18,G21 / F26, E26 / C3,C6 / C18, C21 / A2, X4 / A17, X19.

(B) Four yellow 0.4” wires into: Z11, J9 / Z25, J25 / A8, W10 / A23, W25.

(C) Two green 0.5” wires into: B7, B12 and B22, B27.

(D) One violet 0.7” wire into: i16, i23.

Step 3: Add a Few More Wires.

Insert four blue 0.6” wires into: D3, G7 / D18, G22 / D5, X7 / D20, X21.

Step 4: Add the Resistors.


(A) One 1K resistors (Brown / Black / Red / Gold) into: J3, Y4.

(B) Three 10k resistors (Brown / Black / Orange / Gold) : J18, Y19 / D12, H16 and E18, F18.

(C) One 68k resistor (Blue/Grey/Orange/Gold) into: E3, F3.

Step 5: Add the Capacitors.

Insert two 10uF 50V electrolytic capacitors into: B2 (+), B3 and D26 (+), D27. Two 0.10uF “104” ceramic capacitors into: i8, i9 and B17, B18.

The (+) indicates the longest leg of the capacitor which is positive.

Step 6: Connect the Pizeo Speaker

Connect the 20mm Piezo speaker to: i25(black wire) and i26 (red wire).

Step 7: Connect the Power.

Powering your project can be done in two ways.

(1) If you are using a breadboard power supply module then plug in the USB cable to the module or 2.1 power jack.

(2) If you want to use a standard 9V battery then you will need to do some extra wiring in this step.

9 Volt Battery Wiring:

Connect: 1 x 2.0" wire (red) into (+) power rails Y3 and W3 and 1 x 3.0" (Orange) into (-) power rails Z3 and X3.

Connect 1 x 9 volt battery clip to: W31(red wire) and X31 (black wire) and then clip onto a standard 9V battery. You're done!

Either way once you are powered on you should start hearing your classic siren immediately. Book em dido.

Step 8: About the Breadboard Used in This Project.

This project uses a half size + breadboard or prototype circuit board with 4 power rails. A breadboard is used to connect all your components without the need of using a PCB (Printed Circuit board) and solder. It is a very effective way to test out circuits and rearrange them to your desire. It also allows you to reuse your components for other projects.

BUS LINES: This breadboard has four power lines called BUSES. Buses W (+) and X (-) on the bottom. Buses Y(+) and Z (-) at the top. Buses run horizontally. These are what you connect your power to. W and Y are positive lines for positive wires (usually red) and X and Z for negative wires (usually black). The connection holes on the bus rows are numbered differently to the component rows (the A-J, 1-30 grid). The bus connections start at number 3 and end on number 31. Between each bus section the numbers skip one number. So it’s 3 to 7, 9 to 13, 15 – 19, 21 – 25 and 27-31.

JUMPER WIRE: The color is only used to identify a particular connection. The wire cores are all the same. This wire is used to connect power to your components and to connect components with each other. In the Photo above a green jumper wire is connecting the positive power bus (W12) to component row A14.

COMPONENT ROWS: These rows run vertically and are used to place your components. It is arranged in an alpha numeric grid. A to J, 1 to 30. The green jumper wire above is connected to Bus W12 and Component Row A14.

IC GAP : The horizontal gap in the middle of your board is used to place your ICs or Integrated Circuits.


Electric Dreams Co. Taiwan.

Step 9: Project Circuit Diagram

Step 10: Classic Siren Using 9V Power Supply

Here's a photo of what your finished project should look like. using the 9V battery option.

And a link to a video of the same.

Facebook Video Link.

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    3 years ago

    Thanks for sharing :)