Single Cell 1.5V Hearing Aid

This is a hearing aid circuit with 1.5v supply. This circuit is used to detect very faint sounds, then deliver the sounds to an 8 ohm earpiece. This circuit requires 1.5v input voltage, need only a single cell battery. Here is the schematic diagram of the circuit: This circuit can be assembled in a small board, or you can even […]

Read more

Heartbeat Sensor (Tranduscer)

To build a heart-beat transducer not as difficult as imagined. Circuit below shows a simple heart-beat transducer. This circuit made from an infrared phototransistor and infrared LED.  This transducer works with the principle of light reflection,in this case the light is infrared.  The skin is used as a reflective surface for infrared light. The density of blood in the skin […]

Read more