From d9733c95c05caf81c7b6113e20c9fd69a601ca9d Mon Sep 17 00:00:00 2001
From: shark <cd109876@gmail.com>
Date: Mon, 19 Nov 2018 16:47:52 +0000
Subject: [PATCH] linearize light input according to physics (100% accurate)

---
 acrylic-art-code/acrylic-art-code.ino | 40 ++++++++++++++++-----------
 1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/acrylic-art-code/acrylic-art-code.ino b/acrylic-art-code/acrylic-art-code.ino
index 34cd60e..f37747c 100644
--- a/acrylic-art-code/acrylic-art-code.ino
+++ b/acrylic-art-code/acrylic-art-code.ino
@@ -11,25 +11,29 @@ void setup() {
 void loop() {
   int ss = 20; // sample size for light sensor
   int average = 0;
-  for (int x = 0; x < ss; x++) {
-    average += analogRead(light) / 4;
+  for (int x = 0; x < ss; x++) { 
+    //average += 256-log(256-analogRead(0) / 4) * (256 /5.55); // old linearization
+    
+    //linearization using resistance to lux relationship 
+    average += (1250000.0 * pow(1023-analogRead(0), -1.4059) - 73) / 2.08; 
     delay(3);
   }
   average /= ss;
-  if (oldavg == 0) {
+  //Serial.println(average);
+  if(oldavg == 0) {
       oldavg = average;
     }
   digitalWrite(13, HIGH);
-  if (oldavg != average) {
-    Serial.print("Goal: ");
-    Serial.println(average);
+  if(oldavg != average) {
+  	Serial.print("Goal: ");
+  	Serial.println(average);
   }
-  while (oldavg < average) {
-   oldavg ++;
+  while(oldavg < average) {
+   oldavg += 1;
    setColor(oldavg);
   }
-  while (oldavg > average) {
-   oldavg --;
+  while(oldavg > average) {
+   oldavg -= 1;
    setColor(oldavg);
   }
   digitalWrite(13, LOW);
@@ -65,25 +69,29 @@ void setup() {
 void loop() {
   int ss = 20; // sample size for light sensor
   int average = 0;
-  for (int x = 0; x < ss; x++) {
-    average += analogRead(light) / 4;
+  for (int x = 0; x < ss; x++) { 
+    //average += 256-log(256-analogRead(0) / 4) * (256 /5.55); // old linearization
+    
+    //linearization using resistance to lux relationship 
+    average += (1250000.0 * pow(1023-analogRead(0), -1.4059) - 73) / 2.08; 
     delay(3);
   }
   average /= ss;
+  //Serial.println(average);
   if(oldavg == 0) {
       oldavg = average;
     }
   digitalWrite(13, HIGH);
   if(oldavg != average) {
-    Serial.print("Goal: ");
-    Serial.println(average);
+  	Serial.print("Goal: ");
+  	Serial.println(average);
   }
   while(oldavg < average) {
-   oldavg ++;
+   oldavg += 1;
    setColor(oldavg);
   }
   while(oldavg > average) {
-   oldavg --;
+   oldavg -= 1;
    setColor(oldavg);
   }
   digitalWrite(13, LOW);