From db3ffa126e5462ca63644cf919b6332151d62140 Mon Sep 17 00:00:00 2001
From: Uwe Lippmann <uwe.lippmann@posteo.de>
Date: Thu, 22 Jan 2015 22:04:40 +0100
Subject: [PATCH] Implemented streaming of images over UDP with Ethernet Shield

---
 arduino/rgb_led_matrix.ino | 134 ++++++++++++++-----------------------
 1 file changed, 50 insertions(+), 84 deletions(-)

diff --git a/arduino/rgb_led_matrix.ino b/arduino/rgb_led_matrix.ino
index ea2808a..47de476 100644
--- a/arduino/rgb_led_matrix.ino
+++ b/arduino/rgb_led_matrix.ino
@@ -1,11 +1,15 @@
+#include <SPI.h>
+#include <Ethernet.h>
+#include <EthernetUdp.h>
 #include "Adafruit_NeoPixel.h"
 
 #define PIN 6
-enum {
-  WIDTH=16,
-  HEIGHT=16,
-  N=WIDTH*HEIGHT*3
-};
+#define WIDTH 16
+#define HEIGHT 16
+
+#define UDP_PACKET_MAX_SIZE 768
+#define PIXEL_OFFSET 0x80
+
 // Parameter 1 = number of pixels in strip
 // Parameter 2 = pin number (most are valid)
 // Parameter 3 = pixel type flags, add together as needed:
@@ -15,92 +19,54 @@ enum {
 //   NEO_KHZ800  800 KHz bitstream (e.g. High Density LED strip)
 Adafruit_NeoPixel strip = Adafruit_NeoPixel(WIDTH * HEIGHT, PIN, NEO_GRB + NEO_KHZ800);
 
+// Network configuration
+byte mac[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED};
+IPAddress ip(172, 22, 239, 182);
+unsigned int localPort = 8888;
+
+// buffers for receiving and sending data
+char packetBuffer[UDP_PACKET_MAX_SIZE]; // buffer to hold incoming packet
+
+// Create EthernetUdp instance to send and receive packets over UDP
+EthernetUDP Udp;
+
 void setup() {
-  strip.begin();
-  strip.show(); // Initialize all pixels to 'off'
+  // initialize ethernet device
+  Ethernet.begin(mac, ip);
+  // Start UDP
+  Udp.begin(localPort);
+  strip.begin();  
+  // Initialize all pixels to 'off'
+  for (int i=0; i<256; i++) {
+    strip.setPixelColor(i, strip.Color(0, 0, 0));
+  }
+  strip.show();
   Serial.begin(115200);
+  Serial.println("Ready.");
 }
 
-int j = 0;
-int counter = 0;
-char buf[3*WIDTH*HEIGHT];
-
 void loop() {
-  int incomingByte = 0;  
-  while((Serial.available() > 0) && (incomingByte != -1)) {
-    incomingByte = Serial.read();
-    if (incomingByte != -1) {
-      if(incomingByte == 254)
-        counter = 0;
-      else{
-        buf[counter] = incomingByte;
-        counter++;
-        if (counter >= N)
-          counter = 0;
-      }
-    }
-  }
-  if (counter >= N-1) {
-    for (int i = 0; i < WIDTH*HEIGHT; i++) {
-      strip.setPixelColor(i, strip.Color(buf[3*i], buf[3*i+1], buf[3*i+2]));
+  // if there is data available, read a packet
+  int packetSize = Udp.parsePacket();
+
+  if (packetSize) {
+    // read the packet into packet buffer
+    Udp.read(packetBuffer, UDP_PACKET_MAX_SIZE);
+    Serial.println("Received packet:");
+    Serial.print("Length: ");
+    Serial.println(packetSize);
+    
+    // assume an incoming uncompressed BMP image      
+    // assume we know the pixels start at offset 54
+    for (int i = 0; i < packetSize; i = i + 3) {
+      Serial.print(packetBuffer[i], HEX);
+      Serial.print(packetBuffer[i+1], HEX);
+      Serial.print(packetBuffer[i+2], HEX);
+      Serial.print(" ");
+      strip.setPixelColor(i / 3, packetBuffer[i], packetBuffer[i+1], packetBuffer[i+2]);
     }
+    Serial.print("\n");
     strip.show();
   }  
 }
 
-// Fill the dots one after the other with a color
-void colorWipe(uint32_t c, uint8_t wait) {
-  for(uint16_t i=0; i<strip.numPixels(); i++) {
-      strip.setPixelColor(i, c);
-      strip.show();
-      delay(wait);
-  }
-}
-
-void colorFill(uint32_t c) {
-  for(uint16_t i=0; i<strip.numPixels(); i++) {
-      strip.setPixelColor(i, c);
-  }
-  strip.show();
-//  delay(50);
-}
-
-void rainbow(uint8_t wait) {
-  uint16_t i, j;
-
-  for(j=0; j<256; j++) {
-    for(i=0; i<strip.numPixels(); i++) {
-      strip.setPixelColor(i, Wheel((i+j) & 255));
-    }
-    strip.show();
-    delay(wait);
-  }
-}
-
-// Slightly different, this makes the rainbow equally distributed throughout
-void rainbowCycle(uint8_t wait) {
-  uint16_t i, j;
-
-  for(j=0; j<256*5; j++) { // 5 cycles of all colors on wheel
-    for(i=0; i< strip.numPixels(); i++) {
-      strip.setPixelColor(i, Wheel(((i * 256 / strip.numPixels()) + j) & 255));
-    }
-    strip.show();
-    delay(wait);
-  }
-}
-
-// Input a value 0 to 255 to get a color value.
-// The colours are a transition r - g - b - back to r.
-uint32_t Wheel(byte WheelPos) {
-  if(WheelPos < 85) {
-   return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);
-  } else if(WheelPos < 170) {
-   WheelPos -= 85;
-   return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);
-  } else {
-   WheelPos -= 170;
-   return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);
-  }
-}
-