Initial commit to public repo

CapacitiveSensor.cpp

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+/*
+ CapacitiveSense.h - Capacitive Sensing Library for 'duino / Wiring
+ https://github.com/PaulStoffregen/CapacitiveSensor
+ http://www.pjrc.com/teensy/td_libs_CapacitiveSensor.html
+ http://playground.arduino.cc/Main/CapacitiveSensor
+ Copyright (c) 2009 Paul Bagder
+ Updates for other hardare by Paul Stoffregen, 2010-2016
+ vim: set ts=4:
+
+ Permission is hereby granted, free of charge, to any person obtaining a
+ copy of this software and associated documentation files (the "Software"),
+ to deal in the Software without restriction, including without limitation
+ the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ and/or sell copies of the Software, and to permit persons to whom the
+ Software is furnished to do so, subject to the following conditions:
+
+ The above copyright notice and this permission notice shall be included in
+ all copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ DEALINGS IN THE SOFTWARE.
+*/
+
+#if ARDUINO >= 100
+#include "Arduino.h"
+#else
+#include "WProgram.h"
+#include "pins_arduino.h"
+#include "WConstants.h"
+#endif
+
+#include "CapacitiveSensor.h"
+
+// Constructor /////////////////////////////////////////////////////////////////
+// Function that handles the creation and setup of instances
+
+CapacitiveSensor::CapacitiveSensor(uint8_t sendPin, uint8_t receivePin1, uint8_t receivePin2)
+{
+	// initialize this instance's variables
+	error = 1;
+	loopTimingFactor = 310;		// determined empirically -  a hack
+
+	CS_Timeout_Millis = (200 * (float)loopTimingFactor * (float)F_CPU) / 16000000;
+
+	// Serial.print("timwOut =  ");
+	// Serial.println(CS_Timeout_Millis);
+
+	// get pin mapping and port for send Pin - from PinMode function in core
+
+#ifdef NUM_DIGITAL_PINS
+	if (sendPin >= NUM_DIGITAL_PINS) error = -1;
+	if (receivePin1 >= NUM_DIGITAL_PINS) error = -1;
+	if (receivePin2 >= NUM_DIGITAL_PINS) error = -1;
+#endif
+	pinMode(sendPin, OUTPUT);						// sendpin to OUTPUT
+	pinMode(receivePin1, INPUT);						// receivePin to INPUT
+	pinMode(receivePin2, INPUT);						// receivePin to INPUT
+
+	sBit = PIN_TO_BITMASK(sendPin);					// get send pin's ports and bitmask
+	sReg = PIN_TO_BASEREG(sendPin);					// get pointer to output register
+
+	r1Bit = PIN_TO_BITMASK(receivePin1);
+	r1Reg = PIN_TO_BASEREG(receivePin1);
+
+	r2Bit = PIN_TO_BITMASK(receivePin2);
+	r2Reg = PIN_TO_BASEREG(receivePin2);
+
+	retVal = new unsigned int[2];
+}
+
+// Public Methods //////////////////////////////////////////////////////////////
+// Functions available in Wiring sketches, this library, and other libraries
+
+unsigned int* CapacitiveSensor::sense(uint8_t samples)
+{
+	total1 = 0;
+	total2 = 0;
+
+	noInterrupts();
+	for (uint8_t i = 0; i < samples; i++) {
+		if (!SenseOneCycle())  return nullptr;   // variable over timeout
+	}
+	interrupts();
+
+	retVal[0] = total1;
+	retVal[1] = total2;
+
+	return retVal;
+
+}
+
+// Private Methods /////////////////////////////////////////////////////////////
+// Functions only available to other functions in this library
+
+int CapacitiveSensor::SenseOneCycle(void)
+{
+
+	DIRECT_WRITE_LOW(sReg, sBit);	// sendPin Register low
+	DIRECT_MODE_INPUT(r1Reg, r1Bit);	// r1eceivePin to input (pullups ar1e off)
+	DIRECT_MODE_OUTPUT(r1Reg, r1Bit); // r1eceivePin to OUTPUT
+	DIRECT_WRITE_LOW(r1Reg, r1Bit);	// pin is now LOW AND OUTPUT
+	delayMicroseconds(10);
+	DIRECT_MODE_INPUT(r1Reg, r1Bit);	// r1eceivePin to input (pullups ar1e off)
+
+	DIRECT_MODE_INPUT(r2Reg, r2Bit);	// r2eceivePin to input (pullups ar2e off)
+	DIRECT_MODE_OUTPUT(r2Reg, r2Bit); // r2eceivePin to OUTPUT
+	DIRECT_WRITE_LOW(r2Reg, r2Bit);	// pin is now LOW AND OUTPUT
+	delayMicroseconds(10);
+	DIRECT_MODE_INPUT(r2Reg, r2Bit);	// r2eceivePin to input (pullups ar2e off)
+	DIRECT_WRITE_HIGH(sReg, sBit);	// sendPin High
+
+	while ((total1 < CS_Timeout_Millis)) {  // while total is positive value
+		pin1State = DIRECT_READ(r1Reg, r1Bit);
+		pin2State = DIRECT_READ(r2Reg, r2Bit);
+
+		total1 += !pin1State;
+		total2 += !pin2State;
+
+		if(pin1State && pin2State) break;
+	}
+	//Serial.print("SenseOneCycle(1): ");
+	//Serial.println(total);
+
+	if (total1 > CS_Timeout_Millis) {
+		return -2;         //  total variable over timeout
+	}
+	// set receive pin HIGH briefly to charge up fully - because the while loop above will exit when pin is ~ 2.5V
+	DIRECT_WRITE_HIGH(r1Reg, r1Bit);
+	DIRECT_MODE_OUTPUT(r1Reg, r1Bit);  // receivePin to OUTPUT - pin is now HIGH AND OUTPUT
+	DIRECT_MODE_OUTPUT(r2Reg, r2Bit);  // receivePin to OUTPUT - pin is now HIGH AND OUTPUT
+	DIRECT_WRITE_HIGH(r1Reg, r1Bit);
+	DIRECT_WRITE_HIGH(r2Reg, r2Bit);
+	DIRECT_MODE_INPUT(r1Reg, r1Bit);	// receivePin to INPUT (pullup is off)
+	DIRECT_MODE_INPUT(r2Reg, r2Bit);	// receivePin to INPUT (pullup is off)
+	DIRECT_WRITE_LOW(sReg, sBit);	// sendPin LOW
+
+	while ( (total1 < CS_Timeout_Millis) ) {  // while receive pin is HIGH  AND total is less than timeout
+		pin1State = DIRECT_READ(r1Reg, r1Bit);
+		pin2State = DIRECT_READ(r2Reg, r2Bit);
+
+		total1 += pin1State;
+		total2 += pin2State;
+
+		if(!(pin1State || pin2State)) break;
+	}
+	//Serial.print("SenseOneCycle(2): ");
+	//Serial.println(total);
+	if (total1 >= CS_Timeout_Millis) {
+		return -2;     // total variable over timeout
+	} else {
+		return 1;
+	}
+}