Unsteady
Made by Jessica Yin
Made by Jessica Yin
I wanted to explore how heart rate can implicitly express emotion. A faster heart rate is a reaction to emotions ranging from adrenaline, to fear, to excitement. In this specific case, I wanted to see how an increased heart rate can be linked to negative emotions associated with being off-balance.
Created: December 29th, 2017
#include <Adafruit_ADXL345_U.h>
#include <Servo.h>
#include <Wire.h>
#include <Adafruit_Sensor.h>
const int led2pin = 3;
const int led3pin = 5;
const int led4pin = 6;
const int bpmMax = 220;
const int bpmMin = 70;
int brightness = 255;
int fadeAmount = 10;
long elapsed_time = 0;
long previousMillis = 0;
long previousMillis2 = 0;
long servointerval = 15;
long interval = 1000;
int pos = 0;
int Xaccel = 0;
int Yaccel = 0;
int Zaccel = 0;
Servo myservo; // create servo object to control a servo
// twelve servo objects can be created on most boards
/* Assign a unique ID to this sensor at the same time */
Adafruit_ADXL345_Unified accel = Adafruit_ADXL345_Unified(12345);
void displaySensorDetails(void)
{
sensor_t sensor;
accel.getSensor(&sensor);
Serial.println("------------------------------------");
Serial.print ("Sensor: "); Serial.println(sensor.name);
Serial.print ("Driver Ver: "); Serial.println(sensor.version);
Serial.print ("Unique ID: "); Serial.println(sensor.sensor_id);
Serial.print ("Max Value: "); Serial.print(sensor.max_value); Serial.println(" m/s^2");
Serial.print ("Min Value: "); Serial.print(sensor.min_value); Serial.println(" m/s^2");
Serial.print ("Resolution: "); Serial.print(sensor.resolution); Serial.println(" m/s^2");
Serial.println("------------------------------------");
Serial.println("");
delay(500);
}
void displayDataRate(void)
{
Serial.print ("Data Rate: ");
switch (accel.getDataRate())
{
case ADXL345_DATARATE_3200_HZ:
Serial.print ("3200 ");
break;
case ADXL345_DATARATE_1600_HZ:
Serial.print ("1600 ");
break;
case ADXL345_DATARATE_800_HZ:
Serial.print ("800 ");
break;
case ADXL345_DATARATE_400_HZ:
Serial.print ("400 ");
break;
case ADXL345_DATARATE_200_HZ:
Serial.print ("200 ");
break;
case ADXL345_DATARATE_100_HZ:
Serial.print ("100 ");
break;
case ADXL345_DATARATE_50_HZ:
Serial.print ("50 ");
break;
case ADXL345_DATARATE_25_HZ:
Serial.print ("25 ");
break;
case ADXL345_DATARATE_12_5_HZ:
Serial.print ("12.5 ");
break;
case ADXL345_DATARATE_6_25HZ:
Serial.print ("6.25 ");
break;
case ADXL345_DATARATE_3_13_HZ:
Serial.print ("3.13 ");
break;
case ADXL345_DATARATE_1_56_HZ:
Serial.print ("1.56 ");
break;
case ADXL345_DATARATE_0_78_HZ:
Serial.print ("0.78 ");
break;
case ADXL345_DATARATE_0_39_HZ:
Serial.print ("0.39 ");
break;
case ADXL345_DATARATE_0_20_HZ:
Serial.print ("0.20 ");
break;
case ADXL345_DATARATE_0_10_HZ:
Serial.print ("0.10 ");
break;
default:
Serial.print ("???? ");
break;
}
Serial.println(" Hz");
}
void displayRange(void)
{
Serial.print ("Range: +/- ");
switch (accel.getRange())
{
case ADXL345_RANGE_16_G:
Serial.print ("16 ");
break;
case ADXL345_RANGE_8_G:
Serial.print ("8 ");
break;
case ADXL345_RANGE_4_G:
Serial.print ("4 ");
break;
case ADXL345_RANGE_2_G:
Serial.print ("2 ");
break;
default:
Serial.print ("?? ");
break;
}
Serial.println(" g");
}
void setup() {
pinMode(led2pin, OUTPUT);
pinMode(led3pin, OUTPUT);
pinMode(led4pin, OUTPUT);
Serial.begin(9600);
Serial.println("Accelerometer Test"); Serial.println("");
myservo.attach(9); // attaches the servo on pin 9 to the servo object
/* Initialise the sensor */
if (!accel.begin())
{
/* There was a problem detecting the ADXL345 ... check your connections */
Serial.println("Ooops, no ADXL345 detected ... Check your wiring!");
while (1);
}
/* Set the range to whatever is appropriate for your project */
accel.setRange(ADXL345_RANGE_16_G);
// displaySetRange(ADXL345_RANGE_8_G);
// displaySetRange(ADXL345_RANGE_4_G);
// displaySetRange(ADXL345_RANGE_2_G);
/* Display some basic information on this sensor */
displaySensorDetails();
/* Display additional settings (outside the scope of sensor_t) */
displayDataRate();
displayRange();
Serial.println("");
}
void loop() {
// put your main code here, to run repeatedly:
analogWrite(led2pin, brightness);
analogWrite(led3pin, brightness);
analogWrite(led4pin, brightness);
/* Get a new sensor event */
sensors_event_t event;
accel.getEvent(&event);
/* Display the results (acceleration is measured in m/s^2) */
Serial.print("X: "); Serial.print(event.acceleration.x); Serial.print(" ");
Serial.print("Y: "); Serial.print(event.acceleration.y); Serial.print(" ");
Serial.print("Z: "); Serial.print(event.acceleration.z); Serial.print(" "); Serial.println("m/s^2 ");
Xaccel = event.acceleration.x;
Yaccel = event.acceleration.y;
Zaccel = event.acceleration.z;
Serial.print("Xaccel: ");
Serial.print(abs(Xaccel));
if (abs(Xaccel) > 3 || abs(Zaccel) > 5) {
if (brightness == 255){
brightness = 0;
}
else{
brightness = 255;
}
for (pos = 0; pos <= 90; pos += 3) { // goes from 0 degrees to 180 degrees
// in steps of 1 degree
myservo.write(pos); // tell servo to go to position in variable 'pos'
//delay(1);// waits 15ms for the servo to reach the position
}
for (pos = 90; pos >= 0; pos -= 3) { // goes from 180 degrees to 0 degrees
myservo.write(pos); // tell servo to go to position in variable 'pos'
//delay(1);// waits 15ms for the servo to reach the position
}
delay(100);
}
else if (abs(Xaccel) <= 6 || abs(Zaccel) <= 7) {
if (brightness == 255){
brightness = 0;
}
else{
brightness = 255;
}
for (pos = 0; pos <= 90; pos += 3) { // goes from 0 degrees to 180 degrees
// in steps of 1 degree
myservo.write(pos); // tell servo to go to position in variable 'pos'
//delay(1);// waits 15ms for the servo to reach the position
}
for (pos = 90; pos >= 0; pos -= 3) { // goes from 180 degrees to 0 degrees
myservo.write(pos); // tell servo to go to position in variable 'pos'
//delay(1);// waits 15ms for the servo to reach the position
}
delay(400);
}
else if (abs(Xaccel) >=8 || abs(Zaccel) > 9){
if (brightness == 255){
brightness = 0;
}
else{
brightness = 255;
}
for (pos = 0; pos <= 90; pos += 3) { // goes from 0 degrees to 180 degrees
// in steps of 1 degree
myservo.write(pos); // tell servo to go to position in variable 'pos'
//delay(1);// waits 15ms for the servo to reach the position
}
for (pos = 90; pos >= 0; pos -= 3) { // goes from 180 degrees to 0 degrees
myservo.write(pos); // tell servo to go to position in variable 'pos'
//delay(1);// waits 15ms for the servo to reach the position
}
delay(600);
}
else {
if (brightness == 255){
brightness = 0;
}
else{
brightness = 255;
}
for(pos = 0; pos < 60; pos+=60) { //opens the arm 60 degrees
unsigned long servoMillis = millis();
if(servoMillis - previousMillis > servointerval) //created to delay 15 milliseconds before next pulse
{
previousMillis = servoMillis;
myservo.write(pos); //moves 5 degrees every 15 milliseconds
}
}
unsigned long Starttimer=millis(); //starts one second delay timer?
do {
unsigned long current_time = millis();
elapsed_time = current_time - Starttimer;
}
while(elapsed_time < interval); //leaves loop when 1 second has passed
for(pos = 60; pos >=60; pos-=60) { //closes the arm back to 0 degrees
unsigned long servoMillis2 = millis();
if(servoMillis2 - previousMillis2 > servointerval)
{
previousMillis2 = servoMillis2;
myservo.write(pos);
}
}
delay(15);
}
}Demo video here: https://drive.google.com/file/d/0B0yMpI_ZOcoYN2JnSGY2LUp5UUk/view?usp=sharing
As you knock the person off-balance, the heart rate increases rapidly. Once the person is back on his feet, the heart rate returns to a steadier, more relaxed rhythm. The heart rate is represented by a string of LEDs in the shape of a heart mounted on a protoboard. The protoboard is mounted to a servo, which moves in rhythm with the heart beat. The person is carved from a bar of soap, with an accelerometer embedded in its back.
Process
I first began by individually testing each component’s circuit design and Arduino sketch before combining them.
I started out with the LEDs, testing the circuit in a solderless breadboard before soldering it onto a protoboard. I briefly looked into charlieplexing, before deciding that it was unnecessarily complex for this project. This was surprisingly one of the most time-consuming parts of the project, considering the research I did for the LEDs, charlieplexing, and the careful organization of the components on the protoboard.
The accelerometer was pretty easy to get working, since Adafruit has a library for it, and I have previous experience using accelerometers.
I originally wanted to use a solenoid, since I think the up and down motion of would correspond better to the pulsing of the lights. However, I didn’t want to have to deal with an external power supply or risk ruining my Arduino due to inexperience. However, if I were to give this project a second shot, I would go with the solenoid. I don’t think the servo’s type of motion goes well with the project.
Technical Difficulties
Unfortunately, I couldn’t get both the servo and the LEDs to work simultaneously. I believe it’s an issue with the Arduino sketch, since both functions for the components use the delay function. I chose to keep the LEDs since I think it better communicates my original idea.
I wanted to explore how heart rate can implicitly express emotion. A faster heart rate is a reaction to emotions ranging from adrenaline, to fear, to excitement. In this specific case, I wanted to see how an increased heart rate can be linked to negative emotions associated with being off-balance.