Figure 1.
Schematic Diagram for a Simple Sound-to-Light Converter
Figure 1
shows a simple circuit for converting an audio signal (such as one that
comes from the speaker terminals of a CD player). The circuit basically
consists of a buffer/amplifier stage and three filter circuits: a
high-pass filter, a mid-pass filter, and a low-pass filter. The output
of each filter circuit drives a light-emitting diode of different color.
The input
signal is fed to the buffer stage through C1. The values of RF and RV1
should be chosen so that the buffer is able to drive the three filters
attached to its output. The low-frequency, mid-frequency, and
high-frequency components of the input signal are only allowed to pass
through the low-pass filter (bottom filter), the
mid-pass filter (middle
filter), and the high-pass filter (topmost filter), respectively, thus
separating them from each other.
Changes in
the output of a filter cause its corresponding output LED to turn on and
off. In effect, feeding a continuous audio signal to the input of
this circuit causes the LED's to 'dance'.
See Also:
High-Pass Butterworth Filter;
Low-Pass Butterworth Filter;
Tunable Band-Pass Filter
Go
Back to the PROJECTS Menu
HOME
