Thank you for the comments.
@stuart0 suggestions put into practice gives the following results.
With Red LED Vf=1.7v, R2=220 and VCC=5V. See schematic.
Note: very dim light comes from the LED during switch reading.
Edit:
Logic analyzer view
Minor changes:
/*
Version YY/MM/DD
1.00 16/01/01 Running code
*/
//**********************************************************************
//G l o b a l v a r i a b l e s
//**********************************************************************
//inputs/outputs
const byte heartLED = 13;
const byte secondLED = 12;
const byte SwitchLED = 2; //switch (and LED) is on Arduino pin D02, pushed = LOW
//SRAM variables
byte state = 1;
byte lastSwitchState = 1;
//EEPROM locations
//======================================================================
struct timer
{
//lastMillis = the time this "timer" was (re)started
//waitMillis = delay time (mS) we are looking for
//restart = do we start "this timer" again and again
//enableFlag = is "this timer" enabled/allowed to be accessed
//timeType = true = millis(), false = micros()
//**********************
//For each timer object you need:
//Example:
// timer myTimer = //give the timer a name "myTimer"
// {
// 0, 200UL, true, true, true //lastMillis, waitMillis, restart, enableFlag, timeType
// };
// You have access to:
// myTimer.lastMillis, myTimer.waitMillis, myTimer.restart, myTimer.enableFlag, myTimer.timeType, myTimer.CheckTime()
//**********************
unsigned long lastMillis;
unsigned long waitMillis;
bool restart;
bool enableFlag;
bool timeType;
unsigned long currentTime;
bool CheckTime() //Delay time expired function "CheckTime()"
{
if (timeType == true)
{
currentTime = millis();
}
else
{
currentTime = micros();
}
//is the time up for this task?
if (enableFlag == true && currentTime - lastMillis >= waitMillis)
{
//should this start again?
if (restart)
{
//get ready for the next iteration
lastMillis = currentTime;
}
//time was reached
return true;
}
//time was not reached
return false;
} //END of CheckTime()
}; //END of structure timer
//======================================================================
//**********************************************************************
// Create timer objects and initialize
//**********************************************************************
timer heartBeatLED = //create timer pin13
{
0, 250UL, true, true, true //lastMillis, waitMillis, restart, enableFlag, true=millis/false=micros
};
timer pin2LED =
{
0, 100UL, true, true, true //lastMillis, waitMillis, restart, enableFlag, true=millis/false=micros
};
timer checkSwitches =
{
0, 50UL, true, true, true //lastMillis, waitMillis, restart, enableFlag, true=millis/false=micros
};
// s e t u p ( )
//**********************************************************************
void setup()
{
//**************************************
digitalWrite(heartLED, HIGH); //LED LOW = ON
pinMode(heartLED, OUTPUT);
digitalWrite(secondLED, HIGH); //LED LOW = ON
pinMode(secondLED, OUTPUT);
pinMode(SwitchLED, OUTPUT); //normal state of this pin
digitalWrite(SwitchLED, HIGH); //LED LOW = ON
} // >>>>>>>>>>>>>>>>>> E N D O F s e t u p ( ) <<<<<<<<<<<<<<<<<<<<<
// l o o p ( )
//**********************************************************************
void loop()
{
//***************************
//HeartBeat LED
if (heartBeatLED.CheckTime())
{
//Toggle heartLED
digitalWrite(heartLED, !digitalRead(heartLED));
}
//***************************
if (pin2LED.CheckTime())
{
//Toggle the LED on the SwitchLED pin
digitalWrite(SwitchLED, !state);
state = !state;
}
//***************************
//None blocking code goes here
//***************************
//time to check the Switch(s)?
if (checkSwitches.CheckTime())
{
handleSwitchPresses();
}
} // >>>>>>>>>>>>>>>>>>> E N D O F l o o p ( ) <<<<<<<<<<<<<<<<<<<<<<
//======================================================================
// F U N C T I O N S
//======================================================================
// h a n d l e S w i t c h P r e s s e s( )
//**********************************************************************
void handleSwitchPresses()
{
//store the condition of the output pin
byte PinState = digitalRead(SwitchLED);
//read the switch connected to this pin
pinMode(SwitchLED, INPUT_PULLUP);
byte switchPosition = digitalRead(SwitchLED);
//return the pin to OUTPUT
pinMode(SwitchLED, OUTPUT);
//restore the pin state
digitalWrite(SwitchLED, PinState);
//has the SwitchLED changed state?
if ( switchPosition != lastSwitchState)
{
lastSwitchState = !lastSwitchState;
if (lastSwitchState == LOW) //do LOW stuff
{
//toggle secondLED
digitalWrite(secondLED, !digitalRead(secondLED));
}
else //do HIGH stuff
{
}
} //END of SwitchLED changed state
//Other Switches
} // E n d o f h a n d l e S w i t c h P r e s s e s ( )
//**********************************************************************
//======================================================================
// E N D O F C O D E
//======================================================================
.