SunFounder R3, Manual, Page: 128 / 527

SunFounder uno-and-mega-kit
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Serial.println()
: Takes the same forms as Serial.print(), but it is followed by a carriage return character
(ASCII 13, or ‘\r’) and a newline character (ASCII 10, or ‘\n’).
Map the values
outputValue = map (inputValue, 0 , 1023 , 0 , 255 ); //Convert from 0-1023 proportional to
˓ →
the number of a number of from 0 to 255
map(value, fromLow, fromHigh, toLow, toHigh)
re-maps a number from one range to another. That
is, a value of Fromm would get mapped to one of to Low , and a value of from High to one of thigh , values in-between
to values in-between, etc.
As the range of led Pin (pin 9) is 0-255, we need to map 0-1023 with 0-255.
Display the output value in Serial Monitor in the same way. If you are not so clear about the map() functions, you can
observe the data in the Serial Monitor and analyze it.
Serial . print ( "Output: " ); //print "Output"
Serial . println (outputValue); //print outputValue
Write the value of the potentiometer to LED
analogWrite (ledPin, outputValue); //turn the LED on depending on the output value
Write the output value to
led Pin
and you will see that the luminance of LED changes with your spinning of the
potentiometer knob.
analog Write() : Writes an analog value (PWM wave) to a pin. It has nothing to do with an analog pin, but is just for
PWM pins. You do not need to call the incommode() to set the pin as output before calling
analog Write()
.
6.8.7 Experiment Summary
This experiment can also be changed to others as you like. For example, use the potentiometer to control the time
interval for the LED blinking. It is to use the value read from the potentiometer for delaying, as shown below. Have a
try!
inputValue = analogRead (analogPin);
digitalWrite (ledPin, HIGH );
delay (inputValue);
digitalWrite (ledPin, LOW );
delay (inputValue);
122 Chapter 6. For Mega2560 User