“I‘m feeling blue.”
blue [bluː], adjective
1. a color intermediate between green and violet
2. melancholy, sad or depressed
What shade of blue are you feeling?
This is an artistic-experimental IoT prejoect developed as part as the "easy pieces" MP Project "On The Internet Nobody Knows you0re a toaster", at KISD. More about the project and it's narrative can be found at its Behance Page.
3 needles move over the colour the user selects on a website, with a slider. Each needle has its own site and is theoretically designed to be used by a different user. The value received by the slider at the web, hosted locally, went to a ESP8266 , that passed the value via Software Serial Com to an Arduino, in charge of mapping this values and making three stepper motors move.
I'll overview all of this and highlight some code snippets now.
The website consits of a slider with values ranging from 0 to 359 changing the HUE value of the background. That same HUE is sent in the GET request every time the user releases his mouse button or stops touching the screen.
slider.oninput = function() {
var value = 360 - this.value; //Quick fix: the slider shows colours on the opposite direction as the clock.
document.body.style.backgroundColor = `hsl(${value},65%,60%)`;
}
slider.onmouseup = function() {
var xhr = new XMLHttpRequest();
xhr.open('GET', `http://192.168.0.101/hand1/${this.value}`);
xhr.send();
}
Due to time limitations the website was simply copy pasted three times, one for each needle.
It was hosted on a local server powered by node.js. As WiFi network we used a little TP-LINK hotspot.
The ESP acts as a WiFi web server, using the code provided as an example by Arduino as a basis.
The server isolates and stores in a string the value received via request from each hand website, then adds a number so the Arduino can identify from which hand it came (as I will clarify later), and sends it via software serial to the arduino.
if (req.indexOf("/hand1/") != -1) {
Serial.print("Hand 1: ");
int end = req.indexOf("HTTP") - 1;
String s = req.substring(11, end);
s = "1" + s;
val = s.toInt();
Serial.println(val);
Serial.println(s);
}
The Arduino has to receive move three stepper motors from 0 to 360 degrees. The needles are supposed to be set on red manually (our reference hue = 0 value). These stepper motors are controlled by One EasyDriver each.
To control each motor separately and more easily, the AccelStepper Library is used.
ss1.listen();
delay(2);
if ( ss1.available() ) {
Serial.print("received value: ");
String inString = ss1.readString();
char hand = inString.charAt(0); //1, 2 or 3; depending on the needle.
if ( hand == '1') {
string1 = inString.substring( 1 );
value1 = string1.toInt();
Serial.println(value1);
value1 = map(value1, 0, 359, 0, 1600);
Serial.println("I have mapped:");
Serial.println(value1);
}
if ( hand == '2') {
...
The code inside the loop function checks for software serial communication, gets the string and separates the first character from the rest: it contains the added number identifying the needle that should change its positions. This number gets stored in a variable that gets checked with an if condition.
Inside the if, the string is converted to an integer and mapped - a 360 degree turn in a stepper motor working at 1/8 is 1600. The hue value is therefore transformed to be used properly by the motors, that move to the specified value.
if (hand1.distanceToGo() == 0)
{
delay(5);
hand1.moveTo(value1);
}
if (hand2.distanceToGo() == 0)
{
delay(5);
hand2.moveTo(value2);
}
if (hand3.distanceToGo() == 0)
{
delay(5);
hand3.moveTo(value3);
}
hand1.run();
hand2.run();
hand3.run();
}
The clock is moved by three stepper motors. Three concentric little metal tubes, each smaller than the other, are put together holding one needle each. The motors have a smaller wheel attached to them and bigger one is attached to these small metal tubes, creating, with the aid of rubberbands, a polley transmiting the movement to the needles.
The clock ended up being much wider than expected, and also heating up considerably (because of the stepper motors) - almost enough to guarantee liquid cooling as a feature if a second version was created.
