Project

# Title Team Members TA Documents Sponsor
66 Self-playing Programmable Chromatic Harmonica
 David Zhang
Robert Zhu
Sean Jasin
 Wenjing Song proposal1.pdf
# Team Members:
-Sean Jasin (sjasi3@illinois.edu)

-Robert Zhu (robertz4@illinois.edu)

-David Zhang (dzhan6@illinois.edu)

# Problem:
The harmonica is a versatile, simple, yet technically difficult instrument to play. There is a need for the background music of a live instrument, yet it is difficult to master the harmonica. Some lack the time to practice and learn the harmonica. For others, they may no longer be able to physically play the harmonica, or do not have access to training or musical education. Existing musical devices exist for keyboard and string instruments, but not for wind instruments. There is a need for a self-playing harmonica that can produce melodies without requiring manual lip or breath control.

# Solution:
The solution is a device that is able to play the harmonica. The self playing harmonica consists of multiple subsystems. The power supply provides power at all required voltages for the MCU, air pumps, and electronic pneumatic valves. The harmonica-computer interface connects to both the harmonica and the MCU, and is responsible for controlling the flow of air through the harmonica. It consists of pneumatic tubes, air pumps, and electronic valves. The MCU is responsible for controlling the pumps and valves in the harmonica-computer interface, as well as taking a MIDI file and converting it into a sequence of pump and valve motions. Lastly, songs are uploaded to the MCU through WiFi. We will create a website where the user can upload a MIDI file and that file is then available to play on the device.

# Subsystems:

Power supply

Motor driver

MCU

Harmonica-computer interface

Website for uploading MIDI files

## Power supply (located on the pcb)
The power supply must be capable of supplying 3.3V, and 12V power to the device. The 3.3V power supply is for the MCU and the 12V power supply is used by the pneumatic valves. We will utilize an AL-12100 12V 120W power supply that plugs into a wall outlet. We will then convert the 12 power supply into the signal voltage, 3.3V, on the PCB.

## Motor driver (located on the pcb)
The motor driver will allow the ESP32 to control the DC motor because the output of the GPIO on the MCU cannot provide enough power (GPIO 3V3 @ low current, motor needs 12V). The output of the motor driver will be a 12V PWM signal.

## MCU
For the MCU, we will use an ESP32 for its WiFi capabilities. The MCU has 2 functions: mechanical control and MIDI upload. The mechanical control will take MIDI inputs and play the respective note on the harmonica. This will be controlled by several valves which will allow us to control the airflow into the harmonica.

## Harmonica-Computer Interface

Harmonica:
The harmonica that we will be using for the project will be a Conjurer-brand 10-hole chromatic harmonica. This harmonica was chosen due to its budget-friendliness, as well as its ability to play semitones without the requirement of “bending”, when one uses their tongue to play semitones.

Air pump:
We will use a Mini 555 Dongguang air pump to supply a constant and variable air flow. The airflow will be changed to control for volume, with a maximum of 15 LFM or 0.53 CFM. This should allow us to be able to play 10 notes simultaneously. The airflow of the output will be determined by PWM duty cycle, which will allow us to control the volume of the harmonica. The static pressure requirement of the pump is inconsequential, as harmonicas do not require significant air pressure to play.

Electronic valves:
The electronic valves will consist of 10 Laccimo 2V025-1/4 12V solenoid valves and one Airtac 4V110-08F 5/2 12V solenoid valve. This will allow air input and output from each hole of the harmonica, as well as switching action between blowing air and sucking air.

High-Torque Servo:
To operate the slider, a high-torque servo will be used. The DS3218MG has a sufficient control angle and has enough force (20kg) to operate the lever at a fast speed and in a precise manner.

## Website
Using the ESP32’s WiFi capabilities, the MCU will host a mini server on which a user can upload MIDI files. These MIDI files can then be processed by the MCU to be played by the harmonica.

# Criterion for Success:
The success of this project will be based upon these criteria:

Must be able to blow in and suck out air of all holes in a chromatic harmonica

Must be able to achieve the full range of airflow from 100 to 400 LFM. (equivalent to 0.009 CFM to 0.025 CFM given a 4mm x 10mm sized opening).

Ability to engage and disengage the slide of a chromatic harmonica.

Dynamics/volume control of each played note is accurate and successful.

A .MIDI file is able to be uploaded to the website of the self-playing harmonica system.

A .MIDI file is able to be transmitted to the MCU via WiFi and performed accurately by the self-playing harmonica system.

The system must be robust enough to play for 10 minutes continuously.

Tesla Coil Guitar Amp

David Mengel, Griffin Rzonca

Featured Project

# Tesla Coil Guitar Amp

Team Members:

* Griffin Rzonca (grzonca2)

* David Mengel (dmengel3)

# Problem:

Musicians are known for their affinity for flashy and creative displays and playing styles, especially during their live performances. One of the best ways to foster this creativity and allow artists to express themselves is a new type of amp that is both visually stunning and sonically interesting.

# Solution:

We propose a guitar amp that uses a Tesla coil to create a unique tone and dazzling visuals to go along with it. The amp will take the input from an electric guitar and use this to change the frequency of a tesla coil's sparks onto a grounding rod, creating a tone that matches that of the guitar.

# Solution Components:

## Audio Input and Frequency Processing -

This will convert the output of the guitar into a square wave to be fed as a driver for the tesla coil. This can be done using a network of op-amps. We will also use an LED and phototransistor to separate the user from the rest of the circuit, so that they have no direct connection to any high voltage circuitry. In order to operate our tesla coil, we need to drive it at its resonant frequency. Initial calculations and research have this value somewhere around 100kHz. The ESP32 microcontroller can create up to 40MHz, so we will use this to drive our circuit. In order to output different notes, we will use pulses of the resonant frequency, with the pulses at the frequency of the desired note.

## Solid-state switching -

We will use semiconductor switching rather than the comparably popular air-gap switching, as this poses less of a safety issue and is more reliable and modifiable. We will use a microcontroller, an ESP 32, to control an IR2110 gate driver IC and two to four IGBTs held high or low in order to complete the circuit as the coil triggers, acting in place of the air gap switch. These can all be included on our PCB.

## Power Supply -

We will use a 120V AC input to power the tesla coil and most likely a neon sign transformer if needed to step up the voltage to power our coil.

## Tesla Coil -

Consists of a few wire loops on the primary side and a 100-turn coil of copper wire in order to step up voltage for spark generation. Will also require a toroidal loop of PVC wrapped in aluminum foil in order to properly shape the electric field for optimal arcing. These pieces can be modular for easy storage and transport.

## Grounding rod -

All sparks will be directed onto a grounded metal rod 3-5cm from the coil. The rest of the circuit will use a separate neutral to further protect against damage. If underground cable concerns exist, we can call an Ameren inspector when we test the coil to mark any buried cables to ensure our grounding rod is placed in a safe location.

## Safety -

Tesla coils have been built for senior design in the past, and as noted by TAs, there are several safety precautions needed for this project to work. We reviewed guidelines from dozens of recorded tesla coil builds and determined the following precautions:

* The tesla coil will never be turned on indoors, it will be tested outside with multiple group members present using an outdoor wall outlet, with cones to create a circle of safety to keep bystanders away.

* We will keep everyone at least 10ft away while the coil is active.

* The voltage can reach up to 100kV (albeit low current) so all sparks will be directed onto a grounding rod 3-5cm away, as a general rule of thumb is each 30kV can bridge a 1cm gap.

* The power supply (120-240V) components will be built and tested in the power electronics lab.

* The coil will have an emergency stop button and a fuse at the power supply.

* The cable from the guitar will use a phototransistor so that the user is not connected to a circuit with any power electronics.

# Criterion for Success:

To consider this project successful, we would like to see:

* No safety violations or injuries.

* A tesla coil that produces small visible and audible 3-5cm sparks to our ground rod.

* The coil can play several different notes and tones.

* The coil can take input from the guitar and will play the corresponding notes.

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