Diff: main.cpp

Revision:

0:24709c18bbe0

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Fri Nov 22 10:31:23 2013 +0000
@@ -0,0 +1,107 @@
+#include "mbed.h"
+#include "PCF8591.h"
+ 
+Serial pc(USBTX, USBRX); // tx, rx
+ 
+PCF8591 adc;
+
+float getTrimpotValue()
+{
+    // read a value
+    int v = adc.read(PCF8591::A0);
+        
+    // convert it from 0..255 to 0-3.3V
+    float b = v;
+    return (b / 256) * 3.3;
+}
+
+static void experiment1()
+{
+    pc.printf("Analog input tests\n");
+    while(1) {
+        pc.printf("%f V\n", getTrimpotValue());
+        wait(0.25);
+    }
+}
+
+int getDigit()
+{
+    // read a value
+    int v = adc.read(PCF8591::A0);
+        
+    // convert it from 0..255 to 0-9
+    return (10 * v) / 256;
+}
+
+static void experiment2()
+{
+    pc.printf("Digit input tests\n");
+    while(1) {
+        pc.printf("%d\n", getDigit());
+        wait(0.25);
+    }
+}
+
+int getLightSensorValue(bool filter)
+{
+    static int lastValue = -1;
+
+    // read a value
+    int v = adc.read(PCF8591::A1);
+    
+    if (lastValue == -1) {
+        lastValue = v;
+    }
+    
+    // apply filter
+    if (filter) {
+        lastValue = ((7*lastValue) + v) >> 3;
+    } else {
+        lastValue = v;
+    }
+    
+    return lastValue;
+}
+
+static void experiment3_alt1()
+{
+    pc.printf("Light sensor tests - unfiltered\n");
+    while(1) {
+        pc.printf("%d\n", getLightSensorValue(false));
+        wait(0.25);
+    }
+}
+
+static void experiment3_alt2()
+{
+    pc.printf("Light sensor tests - filtered\n");
+    while(1) {
+        pc.printf("%d\n", getLightSensorValue(true));
+        wait(0.25);
+    }
+}
+
+static void experiment4()
+{
+    int lastValue = -1000;
+    
+    pc.printf("Trimpot tests with threshold\n");
+    while(1) {
+        // read a value
+        int value = adc.read(PCF8591::A0);
+        if (abs(value - lastValue) >= 5) {
+            pc.printf("%d\n", value);
+            lastValue = value;
+        }
+        wait(0.1);
+    }
+}
+
+int main()
+{
+    //experiment1();      // read 0-3.3V
+    //experiment2();      // read digits
+    //experiment3_alt1(); // read light sensor data
+    //experiment3_alt2(); // read filtered light sensor data
+    experiment4();      // read trimpot data, print only big changes
+}
\ No newline at end of file