In this article, you will learn how to improve your collection of Snap Circuits blocks by adding a 555 Timer IC. You will learn the functions the pins on the 555 chip. You will learn that when the 555 is in astable mode, the output of pin 3 is a continuous stream of pulses called a square wave that can be heard on a speaker as a tone. Finally you will learn how to build an astable mode circuit for the 555.

Currently there are no Snap Circuits sets that have the 555 Timer IC. So, you will need to purchase a 555 Timer IC from Allied Electronics or your favorite electronics supplier. If you don't have the Snap Circuits Extreme SC-750 set you can purchase the Snap Circuits Eight-Pin IC Socket block from C&S Sales. Adding these two components to your set of Snap Circuits blocks will allow you to create dozens of circuits built around the 555 Timer IC. The first circuit that I will show you how to build, is a simple square wave tone generator. It was inspired by Forrest Mims III, and it is a very useful circuit that you can use to learn about electronic components such as resistors, and capacitors.

Snap Circuits is an educational toy that teaches electronics with solderless snap-together electronic components. Each component has the schematic symbol and a label printed on its plastic case that is color coded for easy identification. They snap together with ordinary clothing snaps. The components also snap onto a 10 X 7 plastic base grid analogous to a solderless breadboard. There are several Snap Circuits kits that range from a few simple circuits to the largest kit that includes 750 electronic projects.

All the kits include manuals printed in color with easy to follow diagrams to assemble the projects. The illustrations for each project look almost exactly like what the components will look like on the base grid when finished. Because the electronic symbol is printed on each electronic component, once the project is completed, it will look almost exactly like an electronic schematic.

Snap Circuits Parts:

1 Base Grid (11” x 7.7”) # 6SC BG
1 Eight-Pin IC Socket # 6SC ?U8
1 Speaker # 6SC SP
1 Slide Switch # 6SC S1
1 100K ohm Resistor # 6SC R5
1 0.02uF Capacitor # 6SC C1
1 470uF Capacitor # 6SC C5
1 Variable Resistor #6SC RV
1 Whistle Chip # 6SC WC
2 Battery Holder (2-AA) # 6SC B1
1 Single Snap Conductor # 6SC 01
7 Conductor with 2-snaps # 6SC 02
3 Conductor with 3-snaps # 6SC 03
3 Conductor with 4-snaps # 6SC 04
1 Conductor with 5-snaps # 6SC 05
1 Conductor with 6-snaps # 6SC 06
1 Conductor with 7-snaps # 6SC 07

Snap Circuits Parts can be ordered separately from http://cs-sales.net/sncirepa.html (all of the above parts are included in the Snap Circuits Extreme SC-750 set)

Non Snap Circuits Part:

1 555 Timer IC # NTE955M

This part can be ordered from Allied Electronics: http://www.alliedelec.com/search/searchresults.aspx?dsNav=Ntk:Primary%7C555+timer%7C3%7C,Ny:True,Ro:0&dsDimensionSearch=D:555+timer,Dxm:All,Dxp:3&SearchType=0

Optional Snap Circuits Parts (useful for testing the circuit but not required for building the circuit):

1 0.1uf Capacitor # 6SC C2
1 10uf Capacitor # 6SC C3

Here's a video of the tone generator (note: I connected the speaker on the demonstration of the 10uf Capacitor C3 because I wasn't sure if my video camera would pick up the sound):

Step 1: Insert the 555 timer chip into the Snap Circuits IC Socket block

The 555 Timer IC was introduced by a company called Signetics (later bought out by Philips) in 1972 and was designed by Hans R. Camenzind in 1971. The 555 chip has 25 transistors, 15 resistors and 2 diodes in an 8 pin DIP (Dual In-line Package) and looks like a square bug with eight legs. It has a notch at the top and Pin 1 is in the top left corner. (See picture 1) (Source: http://en.wikipedia.org/wiki/File:Signetics_NE555N.JPG)

The Snap Circuits Eight-Pin IC Socket block is picture 2 (source: http://cs-sales.net/eiicso6u8.html)

Insert the 555 timer chip into the Snap Circuits Eight-Pin IC Socket block. Make sure that the notch in the top of the 555 timer chip is aligned with the diagram of the chip pictured on the IC socket block. (See picture 3) (Source: http://www.snapcircuits.net/learning_center/designer)
Good stuff! Some time back I pondered a similar &quot;Snap circuit&quot; DIP8 addition for a PICAXE-08M microcontroller. At the time the easiset way to do this involved gutting a snap sound module &amp; adding the PICAXE (&amp; programming resistors etc) within.<br> <br> This compact approach worked extremely well, although not all 8 pins were brought out. Check the resulting Instructable =&gt;<a href="http://www.instructables.com/id/quotSnap-connectorquot-PICAXE-microcontroller/" rel="nofollow">http://www.instructables.com/id/quotSnap-connectorquot-PICAXE-microcontroller/</a>
Very cool!
looks great!

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Bio: You can try my projects AT YOUR OWN RISK. There's infinite ways to damage or destroy persons and property. I can't think of ... More »
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