initial cleanup and mapping

examples/PiFace/ladder.c

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+/*
+ * ladder.c:
+ *
+ *	Gordon Henderson, June 2012
+ ***********************************************************************
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <math.h>
+
+#include <wiringPi.h>
+#include <piFace.h>
+
+#ifndef	TRUE
+#  define	TRUE	(1==1)
+#  define	FALSE	(1==2)
+#endif
+
+#undef	DEBUG
+
+#define	NUM_LEDS	 8
+
+
+// Map the LEDs to the hardware pins
+//	using PiFace pin numbers here
+
+#define	PIFACE	200
+
+const int ledMap [NUM_LEDS] =
+{
+//  0, 1, 2, 3, 4, 5, 6, 7, 8
+    200, 201, 202, 203, 204, 205, 206, 207
+} ;
+
+
+// Some constants for our circuit simulation
+
+const double vBatt      =      9.0 ;	// Volts (ie. a PP3)
+const double capacitor  =      0.001 ;	// 1000uF
+const double rCharge    =   2200.0 ;	// ohms
+const double rDischarge =  68000.0 ;	// ohms
+const double timeInc    =      0.01 ;	// Seconds
+
+double vCharge, vCap, vCapLast ;
+
+
+
+/*
+ * setup:
+ *	Program the GPIO correctly and initialise the lamps
+ ***********************************************************************
+ */
+
+void setup (void)
+{
+  int i ;
+
+  wiringPiSetupSys () ;
+
+  if (piFaceSetup (200) == -1)
+    exit (1) ;
+
+// Enable internal pull-ups
+
+  for (i = 0 ; i < 8 ; ++i)
+    pullUpDnControl (PIFACE + i, PUD_UP) ;
+
+// Calculate the actual charging voltage - standard calculation of
+//	vCharge = r2 / (r1 + r2) * vBatt
+//
+//
+//   -----+--- vBatt
+//        |
+//        R1
+//        |
+//        +---+---- vCharge
+//        |   |
+//        R2  C
+//        |   |
+//   -----+---+-----
+
+  vCharge = rDischarge / (rCharge + rDischarge) * vBatt ;
+
+// Start with no charge
+
+  vCap    = vCapLast = 0.0 ;
+}
+
+
+/*
+ * introLeds
+ *	Put a little pattern on the LEDs to start with
+ *********************************************************************************
+ */
+
+void introLeds (void)
+{
+  int i, j ;
+
+
+  printf ("Pi Ladder\n") ;
+  printf ("=========\n\n") ;
+  printf ("       vBatt: %6.2f volts\n", vBatt) ;
+  printf ("     rCharge: %6.0f ohms\n", rCharge) ;
+  printf ("  rDischarge: %6.0f ohms\n", rDischarge) ;
+  printf ("     vCharge: %6.2f volts\n", vCharge) ;
+  printf ("   capacitor: %6.0f uF\n", capacitor * 1000.0) ;
+
+// Flash 3 times:
+
+  for (j = 0 ; j < 3 ; ++j)
+  {
+    for (i = 0 ; i < NUM_LEDS ; ++i)
+      digitalWrite (ledMap [i], 1) ;
+    delay (500) ;
+    for (i = 0 ; i < NUM_LEDS ; ++i)
+      digitalWrite (ledMap [i], 0) ;
+    delay (100) ;
+  }
+
+// All On
+
+  for (i = 0 ; i < NUM_LEDS ; ++i)
+    digitalWrite (ledMap [i], 1) ;
+  delay (500) ;
+
+// Countdown...
+
+  for (i = NUM_LEDS - 1 ; i >= 0 ; --i)
+  {
+    digitalWrite (ledMap [i], 0) ;
+    delay (100) ;
+  }
+  delay (500) ;
+}
+
+
+/*
+ * winningLeds
+ *	Put a little pattern on the LEDs to start with
+ *********************************************************************************
+ */
+
+void winningLeds (void)
+{
+  int i, j ;
+
+// Flash 3 times:
+
+  for (j = 0 ; j < 3 ; ++j)
+  {
+    for (i = 0 ; i < NUM_LEDS ; ++i)
+      digitalWrite (ledMap [i], 1) ;
+    delay (500) ;
+    for (i = 0 ; i < NUM_LEDS ; ++i)
+      digitalWrite (ledMap [i], 0) ;
+    delay (100) ;
+  }
+
+// All On
+
+  for (i = 0 ; i < NUM_LEDS ; ++i)
+    digitalWrite (ledMap [i], 1) ;
+  delay (500) ;
+
+// Countup...
+
+  for (i = 0 ; i < NUM_LEDS ; ++i)
+  {
+    digitalWrite (ledMap [i], 0) ;
+    delay (100) ;
+  }
+  delay (500) ;
+}
+
+
+/*
+ * chargeCapacitor: dischargeCapacitor:
+ *	Add or remove charge to the capacitor.
+ *	Standard capacitor formulae.
+ *********************************************************************************
+ */
+
+void chargeCapacitor (void)
+{
+  vCap = (vCapLast - vCharge) *
+	exp (- timeInc / (rCharge * capacitor)) + vCharge ;
+
+#ifdef	DEBUG
+  printf ("+vCap: %7.4f\n", vCap) ;
+#endif
+
+  vCapLast = vCap ;
+}
+
+void dischargeCapacitor (void)
+{
+  vCap = vCapLast *
+	exp (- timeInc / (rDischarge * capacitor)) ;
+
+#ifdef	DEBUG
+  printf ("-vCap: %7.4f\n", vCap) ;
+#endif
+
+  vCapLast = vCap ;
+}
+
+
+/*
+ * ledBargraph:
+ *	Output the supplied number as a bargraph on the LEDs
+ *********************************************************************************
+ */
+
+void ledBargraph (double value, int topLedOn)
+{
+  int topLed = (int)floor (value / vCharge * (double)NUM_LEDS) + 1 ;
+  int i ;
+
+  if (topLed > NUM_LEDS)
+    topLed = NUM_LEDS ;
+
+  if (!topLedOn)
+    --topLed ;
+
+  for (i = 0 ; i < topLed ; ++i)
+    digitalWrite (ledMap [i], 1) ;
+
+  for (i = topLed ; i < NUM_LEDS ; ++i)
+    digitalWrite (ledMap [i], 0) ;
+}
+
+
+/*
+ * ledOnAction:
+ *	Make sure the leading LED is on and check the button
+ *********************************************************************************
+ */
+
+void ledOnAction (void)
+{
+  if (digitalRead (PIFACE) == LOW)
+  {
+    chargeCapacitor () ;
+    ledBargraph (vCap, TRUE) ;
+  }
+}
+
+
+/*
+ * ledOffAction:
+ *	Make sure the leading LED is off and check the button
+ *********************************************************************************
+ */
+
+void ledOffAction (void)
+{
+  dischargeCapacitor () ;
+
+// Are we still pushing the button?
+
+  if (digitalRead (PIFACE) == LOW)
+  {
+    vCap = vCapLast = 0.0 ;
+    ledBargraph (vCap, FALSE) ;
+
+// Wait until we release the button
+
+    while (digitalRead (PIFACE) == LOW)
+      delay (10) ;
+  }
+}
+
+
+/*
+ ***********************************************************************
+ * The main program
+ ***********************************************************************
+ */
+
+int main (void)
+{
+  unsigned int then, ledOnTime, ledOffTime ;
+  unsigned int ourDelay = (int)(1000.0 * timeInc) ;
+  
+  setup     () ;
+  introLeds () ;
+
+// Setup the LED times - TODO reduce the ON time as the game progresses
+
+  ledOnTime  = 1000 ;
+  ledOffTime = 1000 ;
+
+// This is our Gate/Squarewave loop
+
+  for (;;)
+  {
+
+// LED ON:
+
+    (void)ledBargraph (vCap, TRUE) ;
+    then = millis () + ledOnTime ;
+    while (millis () < then)
+    {
+      ledOnAction () ;
+      delay       (ourDelay) ;
+    }
+
+// Have we won yet?
+//	We need vCap to be in the top NUM_LEDS of the vCharge
+
+    if (vCap > ((double)(NUM_LEDS - 1) / (double)NUM_LEDS * vCharge))	// Woo hoo!
+    {
+      winningLeds () ;
+      while (digitalRead (PIFACE) == HIGH)
+	delay (10) ;
+      while (digitalRead (PIFACE) == LOW)
+	delay (10) ;
+      vCap = vCapLast = 0.0 ;
+    }
+
+// LED OFF:
+
+    (void)ledBargraph (vCap, FALSE) ;
+    then = millis () + ledOffTime ;
+    while (millis () < then)
+    {
+      ledOffAction () ;
+      delay        (ourDelay) ;
+    }
+
+  }
+
+  return 0 ;
+}