A sound of ripples
This project invites you to a beach. You can expect that the murmur of surf relaxes you.
After you finish wiring, turn power ON. You hear from the speaker a sound of ripples washing the beach.
The kit at your bedside would put you to a quick sleep.
Have a look at the schematic diagram. The circuit is the same you used before. The oscillators U1A and Q1 generate white noise.
The white noise is amplified by U1B and U1C to produce a sound (noise) of wave. U1D is an oscillator of a square wave having a long interval. It determines the intervals at which the surf rolls in.
The square wave becomes dull as it goes through R15, R16, and C8 before entering the emitter follower Q2. The output from Q2 goes to the VCA (voltage-controlled amplifier) comprised of Q3 - Q6. On the other hand, the sound of wave produced at U1C also enters the VCA.
This wave sound follows the level of the dull waveform sent from Q2, making itself gradually louder and quieter to generate the murmur of ripples. This sound is amplified by the power amplifier U2 and output from the speaker.
You may wish to change the values of components to change the intervals and levels of the wave. You can figure out what components to change.
|Bill Of Materials For A sound of ripples.DSN|
|4||R6, R8, R12, R13||100k|
|4||R20, R21, R24, R25||4K7|
|2||C4, C10||1uF||Digikey 399-3058-2-ND|
|3||C5, C6, C12||0.001uF|
|2||C7, C8||33u||Digikey 399-3058-2-ND|
|2||C13, C14||10uF||Digikey 399-3058-2-ND|
|1 Integrated Circuits|