added tachometer example

.gitignore

@@ -2,4 +2,8 @@
 .clang_complete
 .gcc-flags.json
 .piolibdeps
-*.gch
+*.gch
+lib
+.travis.yml
+!/.travis.yml
+platformio.ini

examples/tachometer/.gitignore

@@ -0,0 +1,4 @@
+.pioenvs
+.piolibdeps
+.clang_complete
+.gcc-flags.json

examples/tachometer/tachometer/tachometer.ino

@@ -0,0 +1,31 @@
+//simple tachometer sending data to serial port
+//it only prints rpm's of the last measure
+
+#include <pcint.h>
+
+#define SensorPin 2
+
+volatile unsigned long t=0;
+volatile unsigned long ot=0;
+unsigned int rpm=0;
+
+void tick() {
+   ot=t;
+   t=millis();
+}
+
+void setup() {
+   Serial.begin(9600);
+   while(!Serial);
+   pinMode(SensorPin,INPUT_PULLUP);
+   PCattachInterrupt<SensorPin>(tick,RISING);
+}
+
+void loop() {
+   if((millis()-t)>300) rpm=0;
+   else if (t!=ot) rpm=60000.0/(float)(t-ot);
+   Serial.print(rpm);
+   Serial.print(" ");
+   Serial.println(t-ot);
+   delay(100);
+}

library.properties

@@ -1,10 +1,10 @@
 name=PCINT r-site.net
-version=4.0.3
+version=4.0.4
 author=Rui Azevedo, ruihfazevedo@gmail.com
 maintainer=neu-rah, ruihfazevedo@gmail.com
 sentence=Arduino Pin change monitor
 paragraph=Attach user function and data to pin change events.
-category=Uncategorized
+category=Signal Input
 dot_a_linkage=true
 url=https://github.com/neu-rah/PCINT
 architectures=*