Electronica

Electronic Project
555 Two-Tone Alarm
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This project is designed to support the Hila demonstration speaker project.

Follow this link for information about getting started inelectronics.

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With the 555 IC mounted find pin 1 and then connect a wire from pin 2 to pin 6.
Notice the black mark I added to indicate the row that pin 1 islocated in.

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Connect a 1k (brown-black-red) resistor from pin 2 to pin 7.

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Connect a 1 uF capacitor from pin 1 to pin 2.
Note that the "-" side of the capacitor connects to pin 1.[pic]

Connect a wire from pin 4 to pin 8.

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Connect a 100 uF capacitor from pin 3 to an unused row.
Note the "+" lead of the capacitor is connected to pin 3.


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Construct a 7cm X 18 cm base out of soft wood (pine is fine).
Tack tow thin strips of aluminum to the base.
One strip along the bottom , the other 7 cm from the bottom.
Aluminum can be cut from disposablecookie sheets.
Note the two wires that are ready to be attached.

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Complete tacking the two strips in place.
Note the two wires are captured by the tacks.

Two "keys" are in place. The keysare made of aluminum 1.5 cm X 3 cm.
Two resistors, 470 Ohm and 1000 Ohm, are laid in place.

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Complete tacking the keys and resistors in place.
Note the resistors are captured by thetacks.
Bend the "keys" up slightly so they don't touch the bottom metal strip.

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Use double sided tape to secure the circuit board in place.
Note orientation and location.

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Close upshowing short wire from aluminum connected to pin 8 and longer wire connected to pin 7.
Red mark indicates row that pin 8 is located in.

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Use double-sided tape to secure battery to base asshown.
Black lead (-) from battery connects to pin 1.
Red lead (+) from battery connects to pin 8.

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The two wires from the demonstration speaker connect to pin 1 and to the unused row...