Introduction: SMD 555 Timer Piano!

Hello everybody! In this instructable I'm going to show you how to make a little piano using the common Timer 555 but with SMD components!

SMD means Surface-Mount Device and those components are mounted or placed directly onto the surface of printed circuit boards.

Let's get started!

Step 1: Step 1: Parts and Tools

The good thing about SMD components is that they are extremely cheap and they come in large quantities so you will have stock for the next time you need them!


1x SMD 555 Timer (Aliexpress:

8x SMD switch buttons (Aliexpress:

8x 1K 0805 SMD resistors (Aliexpress:

1x 10K SMD potentiometer (Aliexpress:

1x SMD 0.1uF SMD capacitor (Aliexpress:

1x SMD 10uF SMD capacitor (Aliexpress:

1x Mini speaker (you could also use a buzzer but the aim is to keep it small!)


1x 9V battery clip (Aliexpress:

Piece of copper PCB (see the measures and the Eagle files below).


Soldering iron


Etching solution and toner transfer paper to make the board.

Step 2: Step 2: Making the Circuit Board

In order to make this board I have used the toner transfer method. Here you have the eagle file. You just need to print it mirrored.

First we need to cut a piece of board. My dimensions were 5,8cm x 3,1cm.

You must be sure that your printer is a LASER one so that this method works. After cleaning the board with alcohol, I ironed the paper in the copper board. Apply heat, a normal iron will do fine, for about 10-15 minutes. Move the iron and push hard to transfer the circuit. Normally, it won't have any difficulty but I do it like this just to be sure.

After this, let the board cool down and then start peeling the sheet carefully. It will come off very easily and... voilà, we have our printed board.


I etched the board with a 50% mix of hydrogen peroxide and hydrochloric acid. Leave it there a couple of minutes until the copper disappears and then, soak the board in water to clean the etching solution.

Now we need to remove the ink. You can use alcohol and a steel wool and after brushing it the ink should come off easily.

Be sure to double check that there aren't short circuits between the tracks, if so, cut the touching tracks with the help of an exacto knife.

And that's it, now we have the board ready to place the components!

Step 3: Step 3: Soldering!

Firstly, we are going to start soldering the buttons. Actually, you can solder whatever you want in first place because as there aren't many parts, none of them will disturb us while we solder others.

This is my method but you can have your own!

Follow the image to solder the buttons.

Then we can solder the 1K resistors. There are 7 of them at the top of the buttons.

After that, solder the 555 Timer in its place. I don't really have a method to solder SMD ICs I just solder them leg by leg with lots of patience!

Now we can solder the potentiometer. I have to admit that this one is a bit difficult but again, with patience, anything can be achieved. With this potentiometer we can adjust the tone to make it sound like a true piano.

You will notice that there is a 1K resistor left. It goes next to the potentiometer, solder it!

We're almost finishing! We have 2 capacitors left. Check the images to know where to solder them!

Now, the speaker (or the buzzer), as they aren't polarized, we can solder them in any position. Just solder it in its position.

And finally, but not least important, the battery clip. Cut it to an appropiate lenght and solder it!

Now we have finished our SMD piano!

Step 4: Step 4: Conclusion

Now, we just need to plug our 9V battery and start playing some good music!

Maybe you will be the next Mozart! Who knows!

I hope you liked this instructable! This little piano is a good idea for a gift because is very small and extremely cheap!

Hope you had as much fun soldering it as I had writing all this instructable for you!

And, if you liked it, don't forget to vote me in the Circuits Contest!

See you in the next one!

Circuits Contest 2016

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Circuits Contest 2016