In this article we discuss a simple circuit which can used to synthesize music by blowing a MIC with breath power from mouth.
The air pressure and vibration generated by the breath on the MIC will create musical effects at the output which can be amplified for further processing.
How it Works
Usually the key switches control the circuits that generate electronic music.
Keyboards not just provide the simplest technical solution for producing fast changing and reproducible tones with a vast range of frequency, but they also have significant popularity because they are counted as an easier instrument to learn than that of musical instruments with string or wind.
Due to that, we haven’t took the initiative to create an electronic oboe, flute or clarinet with the existing circuit.
The technical complexities associated with such instruments would make their electrophonic counterpart considerably expensive.
To avoid that, a relatively simple facility of converting breath to power into a proportional analogue voltage is being presented here.
With the voltage the volume of the music synthesizer can be controlled.
The tones can be controlled by the switches of the keyboard. Undoubtedly, many readers are already thinking of various other application of this converter.
Circuit Description
The mouth operated synthesizer circuit doesn’t operate directly from the breath the user exhaled, rather from the noise generated by this. A thin and flexible tube is being used.
The mouthpiece , may be attached to this – it leads into a closed box. Inside the closed box there are the circuit, as well as an inexpensive microphone is fitted – the structure is depicted in the diagram.
The noise that the microphone receives, gets amplified in IC1, this gain can be adjusted with P1 and the noise can be subsequently corrected by IC2-D1-D2.
Most of the ripples from the output voltage is removed by an active low-pass filter.
The designers have chosen for a compromise between input sensitivity and output ripple, to keep the circuit as simple as it could be.
If the user has an oscilloscope having slow sweep, calibration of the converter won’t be problematic.
First one needs to adjust the value of P1, so that the output voltage with hard blowing into the tube is not being able to cause full-drive.
However, this is depending on the sensitivity of the following instrument.
Secondly, the user needs to adjust P2, so that the output signal is comparatively free of ripples.
At the same time, the converter still reacts if someone breaths normally. A steeper filter must had improved the accessory, however, that would be a bit more costly.