El estetoscopio es un aparato sensible que permite escuchar sonidos muy débiles, siendo un aparato de utilidad para el detective. Con él podemos detectar el ruido de los mecanismos de una bomba de reloj (si es del tipo mecánico) o aún encontrar escondites y hasta oír a través de paredes.

Publicamos este artículo originalmente en uno de nuestros libros de espionaje de la década de los 80. El artículo fue actualizado en 2015.

   En la figura 1 damos una idea de cómo este aparato puede ser usado en la escucha a través de paredes.

 

Figura1 - Escucha a través de paredes
Figura1 - Escucha a través de paredes

 

 

   El circuito propuesto, muy simple se muestra en la figura 2.

 

Figura 2 - El circuito del estetoscopio
Figura 2 - El circuito del estetoscopio

 

 

   La disposición de los componentes en una placa de circuito impreso se muestra en la figura 3.

 

Figura 3 - Placa para el montaje
Figura 3 - Placa para el montaje

 

 

   Para escuchar a través de suelos y paredes, el micrófono debe estar dotado de un sistema acústico especial. Este sistema consiste en un disco pesado de metal con los bordes acolchados como muestra.

 

Figura 4 - El sensor especial
Figura 4 - El sensor especial

 

 

   El disco debe pesar por lo menos 500 gramos para que los sonidos laterales sean amortiguados y que sólo el sonido frontal de la pared o del suelo sea captado y amplificado.

 

CI-1 - TBA820 - circuito integrado0

 

RESISTORES

P1 - 100 k - potenciómetro

R1 - 33 ohms - resistor (naranja, naranja, negro)

R2 - 56 ohms - resistor (verde, azul, negro)

R3 - 10 k - resistor (marrón, negro, naranja)

 

CAPACITORES

C1 - 100 nF - capacitor de cerámica

C2 - 100 pF - capacitor de cerámica

C3. C7 y C8 - 100 uF - capacitor electrolítico

C4 - 47 uF - capacitor electrolítico

C5 - 220 nF - capacitor de cerámica

C6 - 100 nF- capacitor de cerámica o poliéster

C9 - 470 uF - capacitor electrolítico

C10 - 68 uF - capacitor electrolítico

 

VARIOS

MIC - micrófono de eletreto

B1 - 6 V - 4 pilas pequeñas

F - auricular o altavoz de 8 a 40 ohmios

S1 - Interruptor simple

Placa de circuito impreso, soporte para pilas, caja para montaje, hilos, soldadura, etc.

 

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