Errata

Code for blink2 example sketch calls variable "count", but never defines it. I'm a rote beginner, so I'm not entirely sure how to fix it, but I'm happy that I noticed this while reading the book (and then confirmed it by programming it as written to be sure). Awesome book regardless!

The sketch provided did not stop led from flashing, when switch is pressed.
I did small modification to make it work as shown below:

const int ledPin = 13; // output pin for the LED
const int inputPin = 2; // input pin for the switch

void setup() {
pinMode(ledPin, OUTPUT);
pinMode(inputPin, INPUT);
digitalWrite(inputPin,HIGH); // use internal pull-up resistor (Recipe 5.2)
Serial.begin(9600);
}

void loop(){
Serial.println("Press and hold the switch to stop blinking");
int count = blink3(250); // blink the LED 250ms on and 250ms off
Serial.print("The number of times the switch blinked was ");
Serial.println(count);
}

// blink an LED using the given delay period
// return the number of times the LED flashed
int blink3(int period)
{
int result = 0;
int switchVal; //with pull-ups, this will be high when switch is up
switchVal = digitalRead(inputPin);
while(switchVal == HIGH) // repeat this loop until switch is pressed
// (it will go low when pressed)
{
digitalWrite(13,HIGH);
delay(period);
digitalWrite(13,LOW);
delay(period);
result = result + 1; // increment the count
switchVal = digitalRead(inputPin); // read input value
Serial.print("switchVal is ");
Serial.println(switchVal);
Serial.println("Press and hold the switch to stop blinking");
if(switchVal==LOW)
digitalWrite(13,LOW);

}

// here when switchVal is no longer HIGH because the switch is pressed
return result; // this value will be returned
}

In previous example on page 66, a intVal of 1 (which should be 0000000000000001 in 16-bit binary) is inverted and displayed in it's binary form.

The output however is 11111111111111111111111111111110 which is 32-bits.

The author writes on page 67:

"The int value has 16 bits, so when each is flipped, the result is 15 ones followed by a single zero"

This is what you would expect, but what confuses me is the discrepancy between these, because even when I typed in the code myself, it also returned a 32-bit answer.

How can this be if and int value can only have 16 bits????

I think that:

else
result = ceil(num - 0.5);

should read

else
result = ceil(floatValue - 0.5);

Typo error I think num was used inadvertently instead of floatValue

The code use Serial.println on several lines, but the output shown would be generated only with Serial.print, using Serial.Println only on the last field of the print.

the sketch on this page returns errors that blinkLED is not declared

In the solution to adjust the brighness of LEDs, the LEDs are eased in and faded out by writing to the analog pins. However this, solutions contains an 'of by one' error inside the loop. If analogWrite() has a analog value greater than 255, the LEDs go of. This results in a visible flicker because the LEDs are off for 10ms, because the brightness reaches 256 for 10ms.

/*leftout*/

void loop()
{
if ( brightness > 255 )
{
increment = -1;
}
else if ( brightness < 1 )
{
increment = 1;
}
brightness = brightnes + increment; //oops brightness can become 256.

//write the brightness value to the LEDs
analogWrite(firstLed, brigthness);
analogWrite(secondLed, brigthness);
analogWrite(thirdLed, brigthness);

delay(10);
}

I would suggest this fix note the use of 'greater than or equal' comparison operator:
if ( brightness >= 255 )
{
increment = -1;
}

Colour change of the LEDs is somewhat abrupt, due to (IMO) an error in the conversion function.

segmentOffset = scaledHue - (segment * 256) always yields 0 because segment is defined as scaledHue / 256

Replacing it by segmentOffset = scaledHue % 256 gives a much smoother color change.

If you use a common cathode diplay, connect the common pin to GND not to +5V.

Concerning the exercise 7.14 TLC5940 example in Edition 2 Daisy-chain discussion.

For the daisy-chained 16 leds to work, more pins must be connected than are listed in the Tlc5940 discussion.

Add into the bottom paragraph:
* Arduino pin 3 to GSclk (pin18) of each TLC


The Daisy Chained TLC also needs the following pins addressed:

Daisy-Chained Vcc (pin 21) to 5v
Daisy-Chained DCprg (pin 19) to 5v.
Daisy-Chained Gnd (pin22) to Gnd

Just before "Serial.println(duration); in void loop() section of recipe 12.2, you redefine a previously created variable "duration".
This causes it to return a zero value.
Delete the "long" from the duration = millis() - startTime; line and it works fine.

Kind of pissed- absolute beginner at arduino and two of two sketches I've tried have bugs- didn't you guys test the code??

Nice that you have an Errata section to post bugs to, but the file is basically unsearchable... just check your f'ing work before you charge $45 for a book.

The sketches in section 12.6 ("Using a Real-Time Clock") make use of the "DS1307RTC" library. However, this library does not appear to be distributed with the current (1.0.1) Arduino IDE. I did, however, find a version of this library (ie, .h and .cpp files, dated 6 Mar 2010) in the Google code repository and tried installing this locally. However, compiling against this library throws up a whole raft of errors, suggesting some incompatibility with the current suite of libraries.

Table 13.2 as written does not give the correct addresses in HEX from the corresponding A0,A1, A2.
e.g. 0x53 and 0x56 are both shown as 5V, 5V, 0V

Inside the loop routine for the master arduino, there is no statement to actually read the character that is available from the serial port. The first statement inside the if should be "c = Serial.read();"

The ethernet connection is started with one parameter, signifying a DHCP request. However the comment states "... using mac & IP address".
It should read "... using mac & DHCP".
Since it is only comment, the sketch will work alright, however it is confusing to the readers.

The error appears on pages 502, 504, 506, 507 and 509.

The very same line in reported as int duty = map(microseconds, 0,period, 1,1023); in the discussion session on p.614 last line just before "See Also" section.