The inspiration for my LED chair/cushion came from giving mundane inanimate objects such as furniture another layer of interaction with the user. The choice to use temperature as a control value also helps to personify the item
2 months ago
- Quality of code
- Professionalism of the protoshield and power supply
- Appropriate use of technology
- Appearance of the final product
2 months ago
- Neglecting the narrative and interaction
- Not persevering with chair/full artefact
- Limited functionality
- Retrospective blogging
- Not seeking feedback
2 months ago
- Pushbutton to control functions
- Use voltage value to create an RGB colour rather than presets
- Increase temperature range and sensitivity
- Pressure switch to detect if item is being used
- Embed and insulate temperature sensor
- Full battery power
2 months ago
[Flash 10 is required to watch video]
The final version showing the temperature sensor starting, warming up then cooling down
2 months ago
/********************************************************************
Author : Steven Reid
Last Modified : 20th March,2012 Created : 20th February,2012
File : LED_Case.ino
Target Hardware: Arduino Duemilanove /w ATmega328
Version : 1.0
Description : ws2801 LED strip controlled by a TMP36 analog temperature sensor
Includes : http://www.sparkfun.com/datasheets/Components/LED/LED_Strip_Example.pde (LED Strip)
http://www.ladyada.net/learn/sensors/tmp36.html (Temperature sensor)
*********************************************************************************/
int SDI = 2; //Data Wire (Red)
int CKI = 3; //Clock Wire (Green)
int tempPin = 0; //the analog pin the TMP36’s Vout (sense) pin is connected to
//the resolution is 10 mV / degree centigrade with a
//500 mV offset to allow for negative temperatures
int ambient = 0; //Variable that holds the ambient room temperature
int switchTemp = 0; //Temperature variable that controlls the switch case
long ledColor = 0; //Variable that holds the hexadecimal colour value
float temperatureC = 0; //Variable that holds the temperature in degrees centigrade
#define STRIP_LENGTH 64 //Array Lenght(32 LEDs on each strip)
long strip_colors[STRIP_LENGTH]; //Array of LED colour values
//Functions to be carried out on device startup
void setup() {
pinMode(SDI, OUTPUT); //Setting data pin as an output
pinMode(CKI, OUTPUT); //Setting clock pin as an output
pinMode(tempPin, INPUT); //Setting temperature pin as an input
for(int x = 0 ; x < STRIP_LENGTH ; x++) // Clearing the array by filling it with blank values
strip_colors[x] = 0;
getTemp(); // Calling the get temperature function
ambient = temperatureC; //Collecting the ambient temperature value when the device is started
}
//Main program loop
void loop() {
while(1){ //Do forever
getTemp(); // Calling the get temperature function
temp_colour(); // Calling the get colour function
fillArray(); // Calling the fill array function
post_frame(); // Calling the display LED function
}
}
//Reads in the temperature value and converts into degrees c
void getTemp(void) {
//getting the voltage reading from the temperature sensor
int reading = analogRead(tempPin);
// converting that reading to voltage
float voltage = reading * 5.0;
voltage /= 1024.0;
// now convert voltage to temperature(not essential but makes code more readable)
temperatureC = (voltage - 0.5) * 100 ; //converting from 10 mv per degree wit 500 mV offset
switchTemp = (temperatureC - ambient); // creating the value to control the case statement
}
//Using the temperature value to generate the LED colour
void temp_colour (void) {
switch (switchTemp){
//Case statement generating the LED colour
case 1: //if temperature difference is 1 the do….
ledColor = 0x0000FF;//blue(Hex colour value)
break; //Return to main loop
case 2:
ledColor = 0x3D59AB;//cobaltblue
break;
case 3:
ledColor = 0x6495ED;//cornflourblue
break;
case 4:
ledColor = 0xCAE1FF; //lightsteelblue
break;
case 5:
ledColor = 0xCDB5CD;//thistle3
break;
case 6:
ledColor = 0xFFBBFF;//plum1
break;
case 7:
ledColor = 0xEECFA1;//navajowhite2
break;
case 8:
ledColor = 0xEEE685; //khaki2
break;
case 9:
ledColor = 0xFFFF00;//yellow
break;
case 10:
ledColor = 0xEEC900;//gold
break;
case 11:
ledColor = 0xFF8000;//orange
break;
case 12:
ledColor = 0xEE7600;//darkorange
break;
case 13:
ledColor = 0xFF6103; //cadmiumorange
break;
case 14:
ledColor = 0xFF4500;//orangered
break;
case 15:
ledColor = 0xFF0000; //red
break;
//default position to prevent errors
default:
if (switchTemp <= 0){
ledColor = 0x0000FF; //blue
}
else if (switchTemp >= 15){
ledColor = 0xFF0000; //red
}
break;
}
}
//Adds the new led colour and trickles it down the strip
void fillArray(void) {
int x; //0 value for the for loop
//Shuffle all the current colors down one spot on the strip
for(x = (STRIP_LENGTH - 1) ; x > 0 ; x—)
strip_colors[x] = strip_colors[x - 1];
strip_colors[0] = ledColor; //Add the color to the first position on the strip
}
//Takes the current strip color array and pushes it out
void post_frame (void) {
//Each LED requires 24 bits of data
//Once the 24 bits have been delivered, the IC immediately relays these bits to its neighbor
//Pulling the clock low for 500us or more causes the IC to post the data.
//Assigns data to the led
for(int LED_number = 0 ; LED_number < STRIP_LENGTH ; LED_number++) {
long this_led_color = strip_colors[LED_number]; //24 bits of color data
for(byte color_bit = 23 ; color_bit != 255 ; color_bit—) {
//Feed color bit 23 first (red data MSB)
digitalWrite(CKI, LOW); //Only change data when clock is low
long mask = 1L « color_bit;
//The 1’L’ forces the 1 to start as a 32 bit number, otherwise it defaults to 16-bit.
if(this_led_color & mask)
digitalWrite(SDI, HIGH); //Puul data high
else
digitalWrite(SDI, LOW); //Pull data low
digitalWrite(CKI, HIGH); //Data is latched when clock goes high
}
}
digitalWrite(CKI, LOW); //Pull clock low to put strip into reset/post mode
delayMicroseconds(500); //Wait for 500us to go into reset
}
2 months ago
When the LED’s are changing colour the LED’s are flashing on and off too fast. I was hoping the colour change would be more gradual. To overcome this issue I will implement a function that trickles the new colour down the strip.
2 months ago
To refine the final product I removed the sensor and connections from the breadboard and soldered them to a protoshield. I have also wire the onboard pushbutton switch to port 13.
To ensure that the LED strip remained in place around the perimeter of the cushion I have sewn in loops every 10cm to create a channel for the strip to feed through.
2 months ago
To easily convey the idea of a piece of furniture with embedded LED’s if have decided to place the LED’s in a 50x50 cushion. The temperature sensor and Arduino will remain external for demonstration purposes.
The cushion will require two of the LED strips connected together and placed around the edge
2 months ago
To improve the initial version of the coursework I have used a case statement to replace the if/else if and increased the of amount colour increments to 15. Each increment is one degrees centigrade.
