Programmable electronic harmonica having bifurcated air channels

An electronic harmonica having a body with a plurality of air channels, each corresponding to a different musical note, an electric power source, and means for enabling an electrically operated sound producing device to produce said musical notes in response to output signals from strain gages exposed to airflow in the air chambers, each strain gage having a flexible resilient element and an electrical resistance that varies in response to flexure of the resilient element, the improvement comprising:

• first and second strain gages suspended within at least one of the air channels;
• the at least one air channel having an internal divider shelf configured to divide incident airflow entering the at least one air channel into first and second airflows and direct the first airflow to the first strain gage and the second airflow to the second strain gage;
• wherein the internal divider shelf has a curved surface with a 90-degree twist fore to aft;
• and
• wherein the fore portion of the internal divider shelf extends partway across the air channel and the aft portion extends fully across the air channel.

An electronic harmonica having a body with a plurality of air channels, each corresponding to a different musical note, an electric power source, and means for enabling an electrically operated sound producing device to produce said musical notes in response to output signals from strain gages exposed to airflow in the air chambers, each strain gage having a flexible resilient element and an electrical resistance that varies in response to flexure of the resilient element, the improvement comprising:

• a substrate suspended within at least one of the air channels, the substrate having a first strain gage bonded to a forward side of the substrate and a second strain gage bonded to a rearward side of the substrate;
• and
• temperature correction circuitry configured to subtract from an output signal of the first strain gage an output signal of the second strain gage;
• wherein the first strain gage and the second strain gage are bonded to the substrate in an inverse flexure configuration.

An electronic harmonica having a body with a plurality of air channels, each corresponding to a different musical note, an electric power source, and means for enabling an electrically operated sound producing device to produce said musical notes in response to output signals from strain gages exposed to airflow in the air chambers, each strain gage having a flexible resilient element and an electrical resistance that varies in response to flexure of the resilient element, the improvement comprising:

• first and second substrates suspended within at least one of the air channels, each substrate having a forward strain gage bonded to a forward side of the substrate and a rearward strain gage bonded to a rearward side of the substrate;
• temperature correction circuitry configured to subtract from an output signal of the forward strain gage of the first substrate an output signal of the rearward strain gage of the first substrate to generate a first temperature-corrected signal;
• the temperature correction circuitry further configured to subtract from an output signal of the forward strain gage of the second substrate an output signal of the rearward strain gage of the second substrate to generate a second temperature-corrected signal;
• and
• the at least one air channel having an internal divider shelf configured to divide incident airflow entering the at least one air channel into first and second airflows and direct the first airflow to the first substrate and the second airflow to the second substrate.

An instrument for manipulating a variable control signal by mouth, comprising:

• a mouthpiece;
• at least one bifurcated air channel dividing airflow entering the mouthpiece into first and second flow paths;
• a substrate suspended within each of the flow paths, each substrate having a strain gage pair consisting of a first strain gage bonded to a front side of the substrate and a second strain gage bonded to a rear side of the substrate;
• temperature correction circuitry coupled to each strain gage pair and configured to subtract from an output signal of the first strain gage of the strain gage pair an output signal of the second strain gage of the strain gage pair to generate a first temperature-corrected signal for the first flow path and a second temperature-corrected signal for the second flow path;
• and
• detection circuitry configured to transduce airflow blown or drawn through the flow paths and generate a difference signal analogous to flow rate difference between the flow paths.