http://forums.leaflabs.com/topic.php?id=1363 A place to share, learn, and grow... en-US Fri, 22 Jan 2016 00:25:59 +0000 http://bbpress.org/?v=1.0.2 q http://forums.leaflabs.com/search.php http://forums.leaflabs.com/topic.php?id=1363#post-8281 Mon, 20 Feb 2012 12:44:22 +0000 gbulmer 8281@http://forums.leaflabs.com/ <p>defuzo - just to be clear, I don't think that program works well. I was offering an explanation.<br /> I understand how to light an 8x8 LED matrix. That program has nothing to do with "16*4".</p> <p>In the code posted, an 'on' LED is on for less than 1/128th of a screen refresh, which can be improved a lot. When the program is written properly, an 'on' LED would be 'on' for close to 1/8th the screen refresh time. </p> http://forums.leaflabs.com/topic.php?id=1363#post-8278 Mon, 20 Feb 2012 10:46:52 +0000 defuzo 8278@http://forums.leaflabs.com/ <p>dono refreshScreen(), its convoluted. 64 LED connected to 16 pins, 16*4.<br /> Only if Col is low, and Row high, will the LED light. </p> http://forums.leaflabs.com/topic.php?id=1363#post-8271 Sun, 19 Feb 2012 20:39:30 +0000 gbulmer 8271@http://forums.leaflabs.com/ <p>A small comment ...</p> <p>I think this code in refreshScreen():<br /> <pre><code>// ... for (int thisCol = 0; thisCol &lt; 8; thisCol++) { // get the state of the current pixel; int thisPixel = pixels[thisRow][thisCol]; // when the row is HIGH and the col is LOW, // the LED where they meet turns on: digitalWrite(col[thisCol], thisPixel); // turn the pixel off: if (thisPixel == LOW) { digitalWrite(col[thisCol], HIGH); } }</code></pre> <p>has almost the same effect as:<br /> <pre><code>// ... for (int thisCol = 0; thisCol &lt; 8; thisCol++) { digitalWrite(col[thisCol], HIGH); }</code></pre> <p>In the original, I guess an 'on' LED is on for less than 1/128th of the time it takes to refresh the screen, so it'll be quite dim. Is that true, or have I misunderstood something? </p> http://forums.leaflabs.com/topic.php?id=1363#post-8270 Sun, 19 Feb 2012 16:39:27 +0000 gbulmer 8270@http://forums.leaflabs.com/ <p>defuzo - I took the liberty of adding backtick characters around the code to preserve the indentation, and hopefully make it easier to read.</p> <p>What do you mean by 'good speed demo'? Are you comparing Maple with another board like an Arduino, or something else?</p> <p>I think an Arduino can run similar code, and give similar results because human 'persistence of vision' is so very slow by comparison. So I'm unclear what you are asking for. </p> http://forums.leaflabs.com/topic.php?id=1363#post-8269 Sun, 19 Feb 2012 15:11:28 +0000 defuzo 8269@http://forums.leaflabs.com/ <p>(I made another mod, to grasp the speed of the cpu)</p> <p>short:</p> <pre><code>void readSensors() { pixels[x][y] = HIGH; xf = 50 - map(analogRead(A0), 0, 1023, 0, 50) - 25; yf = map(analogRead(A1), 0, 1023, 0, 50) - 25; x = abs((x + xf) % 8 ); y = abs((y + yf) % 8 ); // x = random(0, 8); // y = random(0, 8); pixels[x][y] = LOW; }</code></pre> <p>It will produce something of various random pattern if x/y isnt a natural number.</p> <p>Anybody have any other good speed demo? </p> http://forums.leaflabs.com/topic.php?id=1363#post-8268 Sun, 19 Feb 2012 14:47:55 +0000 defuzo 8268@http://forums.leaflabs.com/ <p>Hello.</p> <p>The included example "RowColumnScanning" didnt work, with same pins as the Arduino.<br /> Pin 15-20 is 13-18, i thk :/</p> <p>Here is my working mod:<br /> (function with same (real) pins on the Arduino)</p> <pre><code>// 2-dimensional array of row pin numbers: const int row[8] = { 2, 7, 20, 5, 13, 19, 12, 17 }; // 2-dimensional array of column pin numbers: const int col[8] = { 6, 11, 10, 3, 18, 4, 8, 9 }; // Analog input pins: const int analogPin1 = 15; const int analogPin2 = 16; // 2-dimensional array of pixels: int pixels[8][8]; // cursor position: int x = 5; int y = 5; void setup() { // initialize the analog input pins as INPUT_ANALOG pinMode(analogPin1, INPUT_ANALOG); pinMode(analogPin2, INPUT_ANALOG); // initialize the I/O pins as outputs: // iterate over the pins: for (int thisPin = 0; thisPin &lt; 8; thisPin++) { // initialize the output pins: pinMode(col[thisPin], OUTPUT); pinMode(row[thisPin], OUTPUT); // take the col pins (i.e. the cathodes) high to ensure that // the LEDS are off: digitalWrite(col[thisPin], HIGH); } // initialize the pixel matrix: for (int x = 0; x &lt; 8; x++) { for (int y = 0; y &lt; 8; y++) { pixels[x][y] = HIGH; } } } void loop() { // read input: readSensors(); // draw the screen: refreshScreen(); } void readSensors() { // turn off the last position: pixels[x][y] = HIGH; // read the sensors for X and Y values: x = 7 - map(analogRead(analogPin1), 0, 4095, 0, 7); y = map(analogRead(analogPin2), 0, 4095, 0, 7); // set the new pixel position low so that the LED will turn on // in the next screen refresh: pixels[x][y] = LOW; } void refreshScreen() { // iterate over the rows (anodes): for (int thisRow = 0; thisRow &lt; 8; thisRow++) { // take the row pin (anode) high: digitalWrite(row[thisRow], HIGH); // iterate over the cols (cathodes): for (int thisCol = 0; thisCol &lt; 8; thisCol++) { // get the state of the current pixel; int thisPixel = pixels[thisRow][thisCol]; // when the row is HIGH and the col is LOW, // the LED where they meet turns on: digitalWrite(col[thisCol], thisPixel); // turn the pixel off: if (thisPixel == LOW) { digitalWrite(col[thisCol], HIGH); } } // take the row pin low to turn off the whole row: digitalWrite(row[thisRow], LOW); } }</code></pre>