Serial Call example question

Projects Interfacing w/ Software on the Computer
1

I know Firmata makes this process much easier, but I'm interested in understanding the serial communication better. I think the example on this page has some errors (or I am misunderstanding something).

  1. first question is about the line:
    firstSensor = analogRead(A0)/4;
    Dividing by four means that the processing sketch is only receiving a value between 0 and 255, which is the opposite of what we want. I deleted the /4 and it works much better.

  2. the second is the line:
    inByte = Serial.read();
    This seems extraneous - inByte is never called again. Is it necessary for some reason or a holdover from an earlier example?

Thanks

2

  1. Is there a question?

  2. The incoming byte is a trigger.

inByte is never called again

You don't 'call' a variable.
Better might have been:

(void) Serial.read ();
3
  1. firstSensor = analogRead(A0)/4;

Probably a hold-over from a sketch where the input is used for PWM output. You were right to remove the /4 since the Processing code expects values from 0 to 1023.

  1. inByte = Serial.read();

This has to be done to acknowledge the "call" part of the "call/response" protocol. If you don't get the byte out of the buffer the (Serial.available() > 0) test will continue to be true and return values will be sent continuously, possibly faster then they can be processed. The "inByte =" part isn't necessary.