Overview:
The goal of this assignment is to show that you can make a simple interactive system with physical controls, and that you can keep a user engaged with your system.
Guideline:
the midterm project can have a Halloween theme. You could make a media controller that controls spooky projections, or a music player that controls the sound in a haunted house, or a tangible interface for things that go bump in the night.
On a conceptual level, your project should help people to enjoy whatever setting it is designed for. If it is a Halloween party, it would have just enough surprises to make it fun, with no chance for injury or psychic trauma.
Initial Sketch
Concept:
- The main theme of the project is ‘making your own Ghost sound’.
It is basically a game that you raise a voice tone and a ghost figure will react to the audience’s tone, moving up and down.
With the voice tone control, the audience have to help the ghost to pass the given hole of the plates.
Purpose of the game:
- Becuase of the reason that the ghost moves up and down based on the voice tone, people will make ‘woooo’ sounds with increasing and. decreasing their tone, naturally making a Ghost sound.
Technical Plan:
Additional Inspiration:
The Movement of the place can be placed on the belt, with the other decoration, so that when a audience place the game, the others can still enjoy the aesthetic aspects of the game as well.
Technical analysis
Oval Conveyor Belt
Motor using External Power
I firstly, decided what kind of sensor to use.
and I found two different type of sensors.
one is Analog type and one is digital type.
So I decided to try with them both to figure out what is better.
Sensor to try
Analog Sensor - KY037
Digital Sensor - sph0645
* Understanding SPH0645
I2S Mic Sensor : Sensor transforming the audio signal to the digital signal
I²S: interface for transferring audio data(Analog Data) into Digital data.
Less noise and clean data.
Main component of the I2S
SD (Serial Data) : pin for transferring audio data
SCK (Serial Clock) : Clock Signal deciding data speed.
WS (Word Select) : Deciding Data Channel.
Popular model for the I2S sensor
SPH0645 : smaller size and higher quality
ICS43432 : low power, high quality.
SPH0645
- 16bit resolution / 48kHz sampling frequency.
- 3.3v
- Built-in filter -> reduce the unnecessary noise and improving the quality.
o VDD – power
o GND
o DOUT – Digital Audio Data
o BCLK – Bit clock
o LRCL – left or right channel.
With Arduino library code…
- VDD – 3.3V
- GND
- BCLK - A3
- DOUT – D4
- LRCL – A2
Testing Code & Sensor
#include <I2S.h>
void setup() {
Serial.begin(115200);
while (!Serial) {
; }
if (!I2S.begin(I2S_PHILIPS_MODE, 8000, 32)) { Serial.println("Failed to initialize I2S!");
while (1); // do nothing
}}
void loop() {
int sample = I2S.read();
if (sample) {float value = sample;
}}
Getting complicated...
If it not possible, I am thinking of using a potentiometer / Time of Flight Distance to control the motor.
Let’s see...
10/8/24
** Memorable day **
I figured out how to study the given code and learn from the challenge.
To utilize the SPH0645 sensor, I checked if the sensor captures the audio signal well enough.
Here is the result:
Checked It captures the audio signal well. It showed the amplitude of the audio.
However, What I need is the frequency of the sound amplitude.
**
FFT.h is a collection of bars that are made of many different frequency range.
It looked like a group of random signals, but when you add ‘start’ and ‘end’ on the Serial.print, you will see the collection of frequency ranges.
**
To get the Frequency data, I asked chatGPT about what is the best resources to use, and here are the two useful resorces:
arduinoFFT.h / arduinoSound.h
Both are based on the FFT arduino library. However, arduinoSound.h was the well structured version upon the arduinoFFT.
So I decided to use arduinoSound.h.
https://www.arduino.cc/reference/en/libraries/arduinosound/fftanalyzer/
Key Note for the arduinoSound:
// sample rate for the input -> read the sample 8000 times per second
const int sampleRate = 8000;
// size of the FFT to compute -> calculate the samples based on 128.
const int fftSize = 128;
// size of the spectrum output, half of FFT size -> Because fft is a mirrored signal, use half.
const int spectrumSize = fftSize / 2;
(i*sampleRate) / fftSize => Frequency of each spectrum.
spectrum[i] => The amplitude of the audio
To increase the density of spectrum with smaller intervals between frequency bins...
- adjust the FFT size and the sampling rate.
1. If you increase the FFT size to 512, the frequency resolution becomes:
8000 / 512=15.625 Hz
2. if you reduce the sampling rate to 4000 Hz, the frequency resolution with an FFT size of 128 will be:
4000 / 128=31.25 Hz
Rotation to Vertical Movement
** Pionion & Rack
Okay, now I am ready to make a ghost moving up & down by a voice control. Servo motor is a rotation movement, and I wanted to convert it to vertical movement. While I was walking around the floor, I found one buddy using Pionion & Rack to convert rotation to vertical movement. Then, I googled about it and found a pre-made SVG file, so that I don’t need to do Math for the gear.
- The movement of Pionion & Rack wasn’t dynamical than I expected.
And I noticed that the greater the teeth of gear’s number is, the more the movement becomes dynamical.
Then made it bigger, and got the result I wanted.
- put the gear on the servo motor and made a lane for the rack, so that it doesn’t go out of the way that it is supposed to move on.
- Then I made a temporary case for the set and put them in the case.
---
Rotation to Vertical Movement -> Pionion & rack = completed.
Making a case & fabricaiton
Let’s start to make a case for the all kits.
I used the laser cutter to make the case and assembled the cut parts together.
Here are the process:
preparing SVG file_ Prototype
Assembling them together_
** If the material is made of Acrylic, you should add 0.003 in expanded gap,
because laser cutter melts the edge while it is cutting, so it becomes smaller than the original plan.
** Used the Acrylic Solvent as a welding tool. It melts the acrylic and you would put them togehter while it was melted,
in a short time, it become harden, helping them become as whole.
Button for Autometic & Playing mode selection
While I was crafting the case, I thought of having a selection mode for the player, so that when they are not playing it moves autometically, and when people are playing it reacts by player’s voice.
Firstly, I used a simple code that we learned through the class:
However, It didn’t work properly because of ‘Delay’ Time when it was in Autometic mode.
So, I asked Chat GPT for help.
it said:
‘Used Async Code’
** What is Async Code?
Simply saying, you can interupt the the flow of codes by button while you are running the code.
It gave the recommendation of using ‘Mills()’ instead of ‘Delay’
Since it’s not using Delay, it will react to the button immediately.
Here is the code:
Stepper Motor
To make the rotating obstacle floating on the grave, I tried using several motors.
1. DC motor
- I tried using DC motor first. Simple to set up, and
already had gone through coltroling speed and how to operate it through the class lab.
Revew:
** The problem was, it wasn’t holding the obstacles strong enough since it easily could rotate to other dirction when it’s forced.
** My solution was to use Stepper Motor. It seems strong enough to hold the obstacle once it’s given the power.
The stepper motor I used for my project is:
Nema 17 Bipolar Stepper Motor
and I used Adafruit TB6612 1.2A DC/Stepper Motor
Here is the note:
- I used <Stepper.h> Library to control the motor.
** Code:
- When the button is pressed, Standby pin lose the power and
then it goes to sleep mode while in Autometic-mode.
- When the button is pressed again, Standby pin get the power, and the play-mode starts, spinning the motor.
Mid Check Point:
Cleaning the circuit board: