Juha Viitanen
Simple autodimmer program with ldr. Calibration is done by setting minimum and maximum brightness. Linear interpolation is used to calculate pwm-output value. AutoDimmer o'lux + Set maximum brightness - Set minimum brightness t Test current settings a Enable/Disable AutoDimmer o'lux
Revision 0:69c5332e36da, committed 2010-12-05
- Comitter:
- bitfox
- Date:
- Sun Dec 05 11:50:05 2010 +0000
- Commit message:
- First release, my first "real" program also.
Changed in this revision
| main.cpp | Show annotated file Show diff for this revision Revisions of this file |
| mbed.bld | Show annotated file Show diff for this revision Revisions of this file |
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Sun Dec 05 11:50:05 2010 +0000
@@ -0,0 +1,95 @@
+/* Simple program for reading ldr.
+ * 1. Read min and max values
+ * 2. test values to output
+ * 3. Use autodimmer to autodim :)
+ *
+ * If you don't have a ldr, you could use a linear variable resistor. etc.
+ * - Juha Viitanen, 5.12.2010, viidakkovekara@gmail.com
+ */
+
+
+#include "mbed.h"
+
+Serial pc(USBTX, USBRX); // tx, rx
+
+PwmOut led(LED1);
+PwmOut led2(LED2);
+PwmOut led3(LED3);
+PwmOut led4(LED4);
+AnalogIn ldr(p20);
+
+static int activate = 0;
+static float min, max;
+float output, reading;
+
+char c;
+
+// aka. linear interpolation
+float outputCalculation(float reading, float min, float max) {
+ return 1.0-(reading-min)*((1.0-0.0)/(max-min));
+}
+
+float rc_filter(float input) {
+ static float Old_input=0;
+ float AB=255.0;
+ float result=0,temp_result=0;
+ unsigned char B=AB-100.0;
+
+ result=input;
+ Old_input = ((input*100.0)/AB) + ((Old_input*B)/AB);
+ temp_result=temp_result+Old_input;
+
+ return temp_result;
+}
+
+int main() {
+ pc.baud(115200);
+ pc.printf("AutoDimmer o'lux\n\r+ Set maximum brightness\n\r- Set minimum brightness\n\rt Test current settings\n\ra Enable/Disable AutoDimmer o'lux\n\r");
+
+ while (1) {
+
+ if (activate == 1) {
+ reading = ldr.read();
+ if (reading < min)
+ reading = min;
+ else if (reading >= max)
+ reading = max;
+ output = outputCalculation(reading, min, max);
+ led = rc_filter(output);
+ }
+
+ if (pc.readable())
+ c = pc.getc();
+ else
+ c = 0;
+
+ switch (c) {
+ case 't':
+ pc.printf("Testing current settings\n\r");
+ reading = ldr.read();
+ if (reading < min)
+ reading = min;
+ else if (reading >= max)
+ reading = max;
+ output = outputCalculation(reading, min, max);
+ pc.printf("ldr %f\n\r", output);
+ led = output;
+ break;
+ case '+':
+ max = ldr.read();
+ pc.printf("max ldr value set to: %f\n\r",max);
+ break;
+ case '-':
+ min = ldr.read();
+ pc.printf("min ldr value set to: %f\n\r",min);
+ break;
+ case 'a':
+ if (activate != 0)
+ pc.printf("Autodimming disabled\n\r");
+ else if (activate == 0)
+ pc.printf("Autodimming enabled\n\r");
+ activate ^= 1;
+ break;
+ }
+ }
+}
\ No newline at end of file
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Sun Dec 05 11:50:05 2010 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed/builds/e2ac27c8e93e