Patent Application
20240412716
Electronic trumpets are known. Two commercially available examples are the Yamaha EZ-TP Trumpet (https://www.yamaha.com/en/about/innovation/collection/detail/0052/) and the Morrison Digital Trumpet (http://www.digitaltrumpet.com.au/). A 2008 Cornell University student project describes an electronic trumpet at https://people.ece.cornell.edu/land/courses/ece4760/FinalProjects/s2008/twc22_bef23/twc22 bef23/index.html. U.S. Pat. No. 3,938,419 (De Rosa) discloses an ELECTRONIC MUSICAL INSTRUMENT. These designs mimic a trumpet in size and function, using attachments to an actual trumpet (Cornell and De Rosa), providing a plastic trumpet replica (Yamaha), or providing a stylized full-size replica of a trumpet (Morrison). A common requirement of prior art is to use a trumpet mouthpiece to control production of trumpet notes.
The Yamaha EZ-TP resembles a full-size trumpet complete with mouthpiece, valves, and bell. According to the web site description, “Players can sing or hum melodies into the mouthpiece.” The presence of breath sounds a note, and the humming frequency selects the interval of notes selected by the valves. The mouthpiece is required to play the Yamaha instrument.
The Morrison Digital Trumpet mimics the size and shape of a trumpet. In the Morrison device a mouthpiece is used to sound notes when a flow of air through the mouthpiece is detected. The mouthpiece is required to play the Morrison instrument.
The Cornell project modifies a standard trumpet by fitting it with optical sensors to detect valve positions and a microphone situated at the trumpet mouthpiece to detect the presence of air flowing through the mouthpiece to sound notes. The mouthpiece is required to play the Cornell instrument.
De Rosa modifies a standard trumpet by fitting it with relays to detect valve positions and a microphone situated at the trumpet mouthpiece to detect the presence of air flowing through the mouthpiece to sound notes. The mouthpiece is required to play the De Rosa instrument.
It would be desirable to have an electronic trumpet that is more compact than a trumpet and which may be played without a mouthpiece to sound the notes. Playing an electronic trumpet with this feature leaves the mouth free while playing the instrument, for example to sing along while playing notes. One can fondly imagine Louis Armstrong playing his own trumpet obbligato while singing, “What a Wonderful World.”
The trumpet is a popular and well-known instrument, which may be chosen by beginning players. However, sounds produced by a person learning the trumpet can be loud and disturbing. Beginning players must learn rudiments of valve positions, embouchure, and breath control before moving on to an advanced skill of playing softly. Practice sessions may be interrupted by family members wishing for silence so they may accomplish tasks requiring concentration such as studying, carrying on a conversation with other family members or talking on the phone. Practicing a trumpet may be best done in certain settings, for example in a well isolated room at home or a band practice room. Practicing a trumpet in other settings such as in an automobile or in a library are not as practical. It would be advantageous to have a method for practicing a trumpet in any setting without disturbing anyone.
Playing a trumpet requires two distinct physical skills. First, positions of the three valves are used to select notes. Because there are three valves, the choice of notes is 2 to the power of 3 or eight notes. Playing notes beyond the eight notes selectable by the valves requires a second skill, which is the ability to vibrate the lips, pressed to the mouthpiece, at various frequencies to select trumpet note intervals. Two methods to produce the required lip vibrations are (a) to produce an audible “buzz” sound while blowing air through the mouthpiece, and (b) to vary lip tension while blowing, with no buzz, causing the lips passively to vibrate due to the moving air, much like the vibration of a double-reed of an instrument such as the bassoon.
Beginning players may be asked to learn mouthpiece technique by causing the lips to vibrate into a mouthpiece before picking up a trumpet. It would be advantageous to separate skills such that valve positions could be learned before mastering correct mouthpiece embouchure and breath discipline. Learning valve positions by playing notes without a mouthpiece may allow a beginner to start learning to play a trumpet before having the physical skill to master embouchure and breath control required with a mouthpiece. Playing an electronic trumpet without requiring a mouthpiece offers a further advantage that it may be played without engaging the player's mouth, leaving it free for other purposes such as singing while simultaneously playing.
These and other advantages may be achieved by an electronic trumpet according to the present invention. Playing it without requiring a mouthpiece separates the skills of valve dexterity and breath/embouchure control. A beginning player may learn valve positions and produce music separately from the challenge of mastering skills required with a mouthpiece. Because it is electronic, it can have a volume control and offer various listening means, including headphones. Because it is electronic, it can sound like other instruments than a trumpet, and play rich chords as notes.
An electronic trumpet emulating the valves of a trumpet. Electronic sensors detect valve positions, and pushbuttons serve the dual purposes of selecting a range of notes selectable by the valves and sounding the notes when activated. A microcontroller translates the valve and button states into MIDI messages suitable for connecting to a MIDI synthesizer or other MIDI device, or to an internal MIDI Synthesizer Integrated Circuit.
A housing comprises body 21, side cap 22 and end cap 23. The side and end caps may be attached to the body using common attachment means such as countersunk screws or internal latches. Opening 27 gives access to connectors mounted on an internal circuit board. Three pushbuttons 24,25,26 protrude from side cap 22 to serve the dual purposes of (a) determining the range of notes selected by depression of the valves, and (b) controlling the sounding of notes. Pressing one of the pushbuttons selects a range of notes selectable by the valves and sounds the selected note. Releasing all three buttons causes any sounding note to be silenced. In this manner an electronic trumpet may be played without a mouthpiece to determine which notes to play and when notes are heard. While an electronic trumpet 20 may contain three buttons, more than three buttons may be employed to increase the range of notes.
The housing may be 3D-printed using a 3D printer such as a Prusa i3Mk3 or similar, using a filament such as PLA (Polylactic Acid).
The hollow cylinders 41,42,43 accept disc magnets 44,4546 and springs 47,48,49, respectively. The disc magnets may be glued in place or captively held in place by compression of springs 57,58,59. Preferred magnets may be Neodymium magnets due to their strong magnetic fields in small sizes. A preferred magnet size may be 10 millimeters in diameter and 2 millimeters thick. The magnets are oriented near the top surfaces of the hollow cylinders, for example 5 millimeters below the top of a cylinder which may be 25 millimeters in length. The lineups of stems, hollow cylinders, disc magnets and springs are inserted into body 21 and held in place by end cap 23 which is attached to the body using common attachment means such as screws or latches. Springs 57,58,59 are chosen to give the same “feel” when valve caps are pressed as with a trumpet. After the internal assemblies are inserted and secured by the end cap, buttons 11,12,13 may be attached to the stems 14,15,16, respectively.
Three Hall-Effect switches 51,52,53 mount on the circuit board. The Hall-Effect switches detect the presence or absence of a magnetic field produced by disc magnets 44,45,46, respectively, in the valve assemblies. When circuit board 50 is mounted into body 21 each Hall-Effect switch aligns with a valve chamber, putting it in proximity to the disc magnet inside the valve. When a valve is depressed its internal disc magnet moves close enough to the Hall-Effect switch for it to switch ON. When a valve is released or is in the inactive position the internal magnet is far enough away from the Hall-Effect switch to switch it OFF. Hall-Effect sensors are available in various configurations including choice of sensitivities and packages. A typical Hall-Effect sensor is the A3144, available from Allegro Semiconductor and others. The A3144 is a Hall-Effect switch, providing an ON or OFF output signal indicating magnetic field presence or absence. Typical sensitivity for the A3144 is to switch its output ON in the presence of a magnetic field of 150-250 Gauss, and OFF when a magnetic field falls below 30-100 Gauss. The A3144 sensitivity range is suitable for the orientation of Hall-Effect switches and disc magnets in the invention.
Manipulation of a valve and its interaction with the Hall-Effect switches may be described using the valve controlled by key 11 as an example, which applies to all valves. When key 11 is not pressed, magnet 44 is far enough away from the Hall-Effect switch 51 that its output is OFF. When a player depresses cap 11, compressing spring 47 and moving hollow cylinder 41 downward, the magnet 44 comes into proximity to Hall-Effect switch 51, causing it to turn ON.
USB port 71 may connect to a development computer 73 using cable 78A to supply power and to load and debug program code to implement the invention. The USB port alternately may connect to a power source 74 such as a battery or USB charger over wire 7B to supply power to the system.
Six GPIO pins connect to Hall-Effect switches 41,42,43 and pushbuttons 24,25,26. Universal Serial Receiver Transmitter (UART) 72 is the interface to a MIDI device such as a synthesizer via connector 57. The input to a MIDI device is a 5 milliampere current loop which powers a light-emitting diode (LED) in an opto-isolator. The current loop comprises a positive voltage source on wire 77 and a current limiting resistor 76 whose value is chosen to provide a minimum of 5 milliamps of current. With a 3.3V source a suitable value of resistor 76 may be 470 Ohms. To be compatible with the MIDI Specification a Microcontroller configures its UART to communicate at the rate of 31,250 baud.
Integrated circuits implementing a MIDI instrument synthesizer are available. The VS1053 MIDI AUDIO CODEC CIRCUIT, available from www.vlsi.fi, contains 127 different instruments and 61 drum sounds. The SAM2695 LOW POWER SINGLE CHIP SYNTHESIZER WITH EFFECTS AND BUILT-IN CODEC, available from www.dream.fr, contains at least 127 different instruments and at least 61 drum sounds. These integrated circuits contain a “TTL-level” MIDI interface so current loop 76,77 of
Program flow proceeds to block 91, where states of the valves and buttons are read. At decision block 92 a test is performed to determine if any of the valves or buttons have changed state since the last time they were read. If not, control reverts to block 91, where the inputs are again read. Loop 91-92 ensures that no MIDI messages are sent if the combination of valves and button states did not change.
If a change is detected in block 92, control passes to block 93 where the button states are checked. If none of the buttons are pressed, block 96 turns off the currently playing note and control passes back to the 91-92 loop to continue checking for new valve or button changes.
If a button is pressed, block 94 translates the combination of valve and button states into a MIDI note number and block 95 transmits a “Note ON” message containing the selected note to the UART. Control then passes back to the 91-92 loop to check for valve or button changes.
Decision block 93 implements the feature that a note is sounded when a button is pressed, and the note is silenced when all buttons are released. Because both valve and button states are checked for changes in blocks 91-92, an electronic trumpet player may change notes either with a button change or a valve change. This can create a “staccato” effect (playing short notes with pauses between them) by maintaining a valve position and tapping a button, or a “legato” effect (gliding between notes without pauses between them) by maintaining a button press and changing valve states.
The MIDI specification describes how messages are sent using a serial protocol, and it assigns numerical values to notes of the scale. Note frequencies are consecutively numbered chromatically with middle C on a piano keyboard having a reference value of 60 and the 88 piano keys ranging from 24 to 108.
The conversion of Hall-Effect switch states and button states to MIDI notes in block 84 may be done according to Table 1.
Table 1 indicates buttons 24,25,26, Hall-Effect switches 24,25,26, a decimal index representing the Hall-Effect switch states considering the Hall-Effect switch states as a 3-bit binary number, the notes of a scale represented by the button and Hall-Effect switch states, and a MIDI note range from 54 to 72, each note corresponding to a particular combination of Hall-Effect switch and button states. Increasing the number of buttons may provide a wider range of notes. A “1” in the Hall Switch columns indicates a valve is depressed and a “0” indicates it is not depressed. The Button column indicates which button is pressed to select the indicated note range. If button 24 is pressed the notes chosen by the three Hall-Effect switch states are MIDI notes 54-60. If button 25 is pressed the notes chosen by the three Hall-Effect switch states are MIDI notes 61-67. If button 26 is pressed the notes chosen by the three Hall-Effect switch states are MIDI notes 67-72. Certain trumpet notes may be played using more than one valve combination. For button 24 MIDI note 57 (the note A) can have Hall-Effect switch states 110 or 001; for button 25 MIDI note 64 (the note E) can have Hall-Effect switch states 110 or 001; and for button 26 MIDI note 68 (the note A-flat) can have Hall-Effect switch states 011 or 001. An additional duplication is MIDI note 67 (G) which may be played as button 25 using Hall-Effect switch state 000 or button 26 using Hall-Effect switch state 101. Of the notes selectable by button 26, Hall-Effect switch combination 111 does not produce a valid note on a trumpet, so this entry is shown as the MIDI note 20, which is a low frequency note used audibly to indicate to the player an invalid button/valve combination.
Table 1 may be reordered to represent the index values in numerical order from 0-7 for each button as seen in Table 2. This makes a MIDI note calculation amenable to a two-dimensional array representation with an outer index representing the button number and an inner index representing the index values 0-7.
The advantages of the present invention include, without limitation, an electronic trumpet that is playable without a mouthpiece. The invention duplicates the valve portion of a trumpet, making it more compact than a trumpet. In place of a mouthpiece to require the flow of air to sound a note, the invention uses pushbuttons both to select a range of notes selectable by the valves and to turn notes on and off. Because the invention produces a MIDI compatible output, it is attachable to MIDI synthesizers, giving the advantage over a trumpet that while played like a trumpet it can sound like any instrument a MIDI synthesizer can reproduce. Leaving the mouth free while playing gives the advantage of allowing a player to sing along or speak while playing the electronic trumpet.
