touchbutton.cpp

00001 #include "mbed.h"
00002 #include "touchbutton.h"
00003 #include "com.h"
00004 
00005 #ifdef DEBUGTOUCHLED
00006 DigitalOut debugled(LED1);
00007 #endif
00008 
00009 float TouchButton::difference() {
00010     return previousValue - currentValue;
00011 }
00012 
00013 TouchButton::TouchButton(PinName ain, PinName din, PinName dout, float threshold, int debounceTime, char *nm) :   sensor(ain), charger(din), ground(dout) {
00014 
00015     setThreshold(threshold);
00016     setDebounceTime(debounceTime);
00017     AnalogIn sensor(ain);
00018     DigitalIn charger(din);
00019     DigitalOut ground(dout);
00020     ground.write(0);
00021     timer.start();
00022     sample();
00023     storeValue();
00024     strcpy(name,nm);
00025 #ifdef DEBUGTOUCH
00026         com.printf("INIT BUTTON %s\r\n",name);
00027 #endif
00028 }
00029 
00030 void TouchButton::storeValue() {
00031     previousValue=currentValue;
00032 }
00033 
00034 void TouchButton::setThreshold(float level) {
00035     analogThreshold = level;
00036 }
00037 
00038 void TouchButton::setDebounceTime(int t) {
00039     timeout_ms = t;
00040 }
00041 
00042 bool TouchButton::checkState() {
00043     float diff;
00044 #ifdef DEBUGTOUCH
00045         com.printf("CHECK BUTTON\r\n");
00046 #endif
00047  
00048     charge();
00049 #ifdef DEBUGTOUCH
00050         com.printf("CHARGE BUTTON\r\n");
00051 #endif    
00052     sample();
00053 #ifdef DEBUGTOUCH
00054         com.printf("CHARGE & SAMPLE BUTTON %s\r\n",name);
00055         com.printf("Value:%3.2f\r\n", currentValue);
00056 #endif
00057 
00058 
00059     diff=previousValue - currentValue;
00060     storeValue();
00061     if (diff > analogThreshold && timer.read_ms() > timeout_ms) {
00062         timer.reset();
00063 #ifdef DEBUGTOUCH
00064         com.printf("TOUCH %s\r\n", name);
00065 #endif
00066 #ifdef DEBUGTOUCHLED
00067         //Toggle LED to show touch was registered
00068         if (debugled.read()==1)
00069             debugled=0;
00070         else
00071             debugled=1;
00072 #endif
00073         return true;
00074     } else {
00075         return false;
00076     }
00077 
00078 }
00079 
00080 float TouchButton::sample() {
00081 
00082     float sum = 0;
00083     for (int i=0; i<NUMSAMP;i++) {
00084         float value = sensor.read();
00085         sum = sum + value;
00086     }
00087     currentValue = sum/NUMSAMP;
00088     return currentValue;
00089 
00090 }
00091 
00092 void TouchButton::charge() {
00093     charger.mode(PullUp);
00094     charger.mode(PullNone);
00095     wait(.005);
00096 
00097 }