Spidey Wall is the name for a physical wall lit up by multiple addressable LED strips. This program is an LPC1768 web server to control the wall from a browser.

Dependencies:   EthernetInterfacePlusHostname RdWebServer mbed-rtos mbed

This project is part of a Light-Wall using addressable LED strips (WS2801). I have published a few posts on my blog about the construction of the wall and building a game to play on it (PacMan). I have also had a guest post from a friend who has set his children the task of producing some interesting animations. The original post is http://robdobson.com/2015/07/spidey-wall/ /media/uploads/Bobty/20130722_112945_img_9674_62895-1184x1579.jpg

So far, however, I hadn't fully connected the physical (and electronic) wall with the web-browser creations to drive it. This project is hopefully the final link. A fast and reliable web server using REST commands to drive the 1686 LEDs in the Spidey Wall from code running in a browser (say on an iPad while you are playing a game).

The approach taken here results in the ability to control the RGB values of all 1686 LEDs at a rate of 20 frames per second.

A blog post describing the whole thing is here:

http://robdobson.com/2015/08/a-reliable-mbed-webserver/

Revision:
0:887096209439
Child:
1:362331cec9b7
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ledstrip.cpp	Tue Aug 18 16:03:29 2015 +0000
@@ -0,0 +1,285 @@
+#include "ledstrip.h"
+#include "colourconverters.h"
+#include "stddef.h"
+
+#define SPIF 0              // SPI interrupt flag bit
+#define SSP_IMSC_TX_RDY 3
+#define SSP_IMSC_BITMASK 0x0f
+
+volatile int mCurPos0;
+int mEndPos0;
+volatile int mCurPos1;
+int mEndPos1;
+volatile bool mShowingLeds0;
+volatile bool mShowingLeds1;
+unsigned char* pLedValues;
+bool inISR;
+
+extern "C" void spi0_isr()
+{
+    if (mCurPos0 < mEndPos0)
+    {
+        LPC_SSP0->DR = pLedValues[mCurPos0];  // write to FIFO data register
+        mCurPos0++;
+    }
+    else
+    {
+        // Turn off interrupts
+        LPC_SSP0->IMSC = 0;
+        mShowingLeds0 = false;
+    }
+}
+
+extern "C" void spi1_isr()
+{
+    if (mCurPos1 < mEndPos1)
+    {
+        LPC_SSP1->DR = pLedValues[mCurPos1];  // write to FIFO data register
+        mCurPos1++;
+    }
+    else
+    {
+        // Turn off interrupts
+        LPC_SSP1->IMSC = 0;
+        mShowingLeds1 = false;
+    }
+}
+
+ledstrip::ledstrip(int length, int splitPoint)
+{
+    mpLedValuesA = 0;
+    mpLedValuesB = 0;
+    mpCurLedValues = 0;
+
+    // SPI0 (using SSP 0 in 1768 chip)
+    mpSPI0 = new SPI(p11, NC, p13);
+    mpSPI0->format(8,0);
+    mpSPI0->frequency(500000);    
+    LPC_SSP0->IMSC = 0; // initially no interrupts requested
+    NVIC_SetVector(SSP0_IRQn,( uint32_t ) spi0_isr);
+    NVIC_ClearPendingIRQ(SSP0_IRQn);
+    NVIC_SetPriority(SSP0_IRQn, 2);
+    NVIC_EnableIRQ(SSP0_IRQn);
+
+    // SPI1 (using SSP 1 in 1768 chip)
+    mpSPI1 = new SPI(p5, NC, p7);
+    mpSPI1->format(8,0);
+    mpSPI1->frequency(500000);    
+    LPC_SSP1->IMSC = 0; // initially no interrupts requested
+    NVIC_SetVector(SSP1_IRQn,( uint32_t ) spi1_isr);
+    NVIC_ClearPendingIRQ(SSP1_IRQn);
+    NVIC_SetPriority(SSP1_IRQn, 2);
+    NVIC_EnableIRQ(SSP1_IRQn);
+    
+    // Enable interrupts
+    __enable_irq();
+        
+    // Resize the string length
+    Resize(length, splitPoint);
+}
+
+ledstrip::~ledstrip()
+{
+    delete mpLedValuesA;
+    delete mpLedValuesB;
+}
+
+bool ledstrip::Resize(int length, int splitPoint)
+{
+    if (mShowingLeds0 || mShowingLeds1)
+        return false;
+    if (mpLedValuesA != 0)
+        delete mpLedValuesA;
+    if (mpLedValuesB != 0)
+        delete mpLedValuesB;
+    mLedsBufSize = length*mColoursPerLed;
+    mpLedValuesA = new unsigned char[mLedsBufSize];
+    mpLedValuesB = new unsigned char[mLedsBufSize];
+    mpCurLedValues = mpLedValuesA;
+    mLedsInStrip = length;
+    mSplitPoint = splitPoint;
+    Clear();
+    return true;
+}
+
+void ledstrip::Clear()
+{
+/*    Timer timr;
+    timr.start();
+    for (int i = 0; i < mLedsInStrip*mColoursPerLed; i++)
+        mpCurLedValues[i] = 0;
+    timr.stop();
+    printf("ClearTime loop %d\n", timr.read_us());  // Result is 863uS for 2500 x 3colour LEDS
+    timr.reset();
+    timr.start();
+ */
+    memset(mpCurLedValues, 0, mLedsBufSize);
+ /*   timr.stop();
+    printf("ClearTime memset %d\n", timr.read_us());  // Result is 35uS for 2500 x 3 colour LEDS
+*/
+}
+
+unsigned char* ledstrip::GetBuffer()
+{
+    return mpCurLedValues;
+}
+
+int ledstrip::GetBufferSizeinBytes()
+{
+    return mLedsBufSize;
+}
+
+bool ledstrip::IsBusy()
+{
+    return mShowingLeds0 || mShowingLeds1;
+}
+
+// Fill - solid colour
+void ledstrip::Fill(int startLed, int numLeds, 
+                int r1, int g1, int b1)
+{
+/*    Timer timr;
+    timr.start();
+*/
+    if ((startLed < 0) || (startLed >= mLedsInStrip))
+        return;
+    if (numLeds >= mLedsInStrip - startLed)
+        numLeds = mLedsInStrip - startLed;
+    int pos = startLed * mColoursPerLed;
+    unsigned char* pBuf = GetBuffer();
+    for (int i = 0; i < numLeds; i++)
+    {
+        pBuf[pos] = (unsigned char) r1;
+        pBuf[pos+1] = (unsigned char) g1;
+        pBuf[pos+2] = (unsigned char) b1;
+        pos += mColoursPerLed;
+    }
+/*    timr.stop();
+    printf("Fill solid %d\n", timr.read_us()); // Fill 50 LEDS solid colour = 11uS
+    */
+}
+
+// Fill - with interpolation of colours using HSV colour space
+void ledstrip::Fill(int startLed, int numLeds, 
+                int r1, int g1, int b1, 
+                int r2, int g2, int b2)
+{
+/*    Timer timr;
+    timr.start();
+    */
+    if ((startLed < 0) || (startLed >= mLedsInStrip))
+        return;
+    if (numLeds >= mLedsInStrip - startLed)
+        numLeds = mLedsInStrip - startLed;
+    int pos = startLed * mColoursPerLed;
+    RgbColor startRGB(r1,g1,b1);
+    HsvColor startHsv = RgbToHsv(startRGB);
+    RgbColor endRGB(r2,g2,b2);
+    HsvColor endHsv = RgbToHsv(endRGB);
+    int curH = startHsv.h << 16;
+    int curS = startHsv.s << 16;
+    int curV = startHsv.v << 16;
+    int interpSteps = numLeds - 1;
+    if (interpSteps < 1)
+        interpSteps = 1;
+    int incH = ((endHsv.h - startHsv.h) << 16) / interpSteps;
+    int incS = ((endHsv.s - startHsv.s) << 16) / interpSteps;
+    int incV = ((endHsv.v - startHsv.v) << 16) / interpSteps;
+    // Since H is a polar value we need to find out if it is best to go clockwise or anti-clockwise
+    if (endHsv.h > startHsv.h)
+    {
+        if (endHsv.h-startHsv.h > 128)
+            incH = ((startHsv.h-endHsv.h) << 16) / interpSteps;
+    }
+    else
+    {
+        // Go "round the top" using modulo result
+        if (startHsv.h-endHsv.h > 128)
+            incH = ((endHsv.h + 255 - startHsv.h) << 16) / interpSteps;
+    }
+    
+//    printf("StartHSV %d %d %d EndHSV %d %d %d IncHSV %d %d %d\n", startHsv.h, startHsv.s, startHsv.v, endHsv.h, endHsv.s, endHsv.v, incH, incS, incV);
+    unsigned char* pBuf = GetBuffer();
+    for (int i = 0; i < numLeds; i++)
+    {
+        RgbColor colrVal = HsvToRgb(HsvColor((curH>>16)&0xff,curS>>16,curV>>16));
+        pBuf[pos] = colrVal.r;
+        pBuf[pos+1] = colrVal.g;
+        pBuf[pos+2] = colrVal.b;
+//        printf("HSV %d %d %d RGB %d %d %d\n", curH>>16, curS>>16, curV>>16, colrVal.r, colrVal.g, colrVal.b);
+        pos += mColoursPerLed;
+        curH = curH + incH;
+        curS = curS + incS;
+        curV = curV + incV;
+    }
+    /*
+    timr.stop();
+    printf("Fill gradient %d\n", timr.read_us());  // Fill gradient 50 LEDS = 64uS
+    */
+}
+
+    
+void ledstrip::ShowLeds()
+{
+    // Check if busy
+    while (mShowingLeds0 || mShowingLeds1)
+        ;
+    wait_us(750);
+    
+    // Set up start points
+    mCurPos0 = 0;
+    mEndPos0 = mSplitPoint*mColoursPerLed;
+    mCurPos1 = mSplitPoint*mColoursPerLed;
+    mEndPos1 = mLedsInStrip*mColoursPerLed;
+    
+    // Set the buffer for the ISRs
+    pLedValues = mpCurLedValues;
+    
+    // Flip the current buffer to the alternate one for interleaved writing
+    if (mpCurLedValues == mpLedValuesA)
+        mpCurLedValues = mpLedValuesB;
+    else
+        mpCurLedValues = mpLedValuesA;
+    
+    // Enable interrupts
+    mShowingLeds0 = true;
+    LPC_SSP0->IMSC = (1 << SSP_IMSC_TX_RDY) & SSP_IMSC_BITMASK;
+    
+    // Check if second strip is used
+    if (mSplitPoint < mLedsInStrip)
+    {
+        LPC_SSP1->IMSC = (1 << SSP_IMSC_TX_RDY) & SSP_IMSC_BITMASK;
+        mShowingLeds1 = true;
+    }
+ //   for (int q = 0; q < mLedsInStrip*3; q+=3)
+ //       printf("%d %02x%02x%02x\n", q/3, mpLedValues[q], mpLedValues[q+1], mpLedValues[q+2]);
+/*
+    int pos1 = 0;
+    int pos2 = mSplitPoint * mColoursPerLed;
+    for (int j = 0; j < mMaxChainLength; j++)
+    {
+        for (int k = 0; k < mColoursPerLed; k++)
+        {
+            unsigned char tval1 = 0;
+            if (pos1 + k < mLedsBufSize)
+                tval1 = mpLedValues[pos1 + k];
+            unsigned char tval2 = 0;
+            if (pos2 + k < mLedsBufSize)
+                tval2 = mpLedValues[pos2 + k];
+            for (int i = 0; i < 8; i++)
+            {
+                dat1 = (tval1 & 0x80) != 0;
+                tval1 = tval1 << 1;
+                dat2 = (tval2 & 0x80) != 0;
+                tval2 = tval2 << 1;
+                clk = 1;
+                clk = 0;
+                wait_us(1);
+            }
+        }
+        pos1 += mColoursPerLed;
+        pos2 += mColoursPerLed;
+    }
+    wait_us(750);
+*/
+}