Programming problem I need both if else cases to work but only else loop is running

Question

#include <SoftwareSerial.h>
#include <Servo.h>
Servo myservo1, myservo2, myservo3;
int bluetoothTx = 14;
int bluetoothRx = 15;
SoftwareSerial bluetooth(bluetoothTx, bluetoothRx);
void setup()
{
myservo1.attach(9);
//Setup usb serial connection to computer
Serial.begin(9600);
//Setup Bluetooth serial connection to android
bluetooth.begin(9600);
 }
void loop()
 {
 if(bluetooth.available()>0)
 { 
 if(bluetooth.available()>=4)
 { 
 char buffer[4];
 for(int i=0;i<4;i++)
 { 
 buffer[i]=bluetooth.read();
 }
 int incomingValue = atoi(buffer); 
 if(incomingValue>=1000 && incomingValue<=1360)
 {
 unsigned int servopos = bluetooth.read();
 unsigned int servopos1 = bluetooth.read();
 unsigned int realservo = (servopos1 * 256) + servopos;
 if (realservo >= 1000 && realservo < 1360) 
 {
 int servo1 = realservo;
 servo1 = map(servo1, 1000, 1360, 0, 360);
 myservo1.write(servo1);
 Serial.println("servo 1 ON");
 delay(10); 
 }
 }
 }
 if(bluetooth.available()==2)
 {
 char inbit=bluetooth.read(); 
 if(inbit=='A'||inbit=='D');
 {
 char myval= bluetooth.read();
 if(myval== 'A')
 {
 myservo1.attach(9);
 }
 if(myval== 'D')
 {
 myservo1.detach();
 }
 } 
 }
 }
 }

• ott--: You need to add, what values you expect from bluetooth during one loop-call. Calling bluetooth.read() twice in an if may not be that what you want.
• Majenko: I think you are lacking a basic understanding of how serial works.
• Majenko: Also lacking a basic understanding of how to write an if statement.
• ott--: Your new code is still a mess. Please provide an abstract algorithm of what should be done.

Answer 1

There are so many things wrong with that program I can't begin to sort it out.

Here's some of the most glaringly obvious errors:

if(bluetooth.read() >=0 && bluetooth.read() <=360)

Read a character. Check it's at least 0. Read a second character. Check it's less than 360. Since characters are between 0 and 255 that will always succeed if there is one character of any form to read (if there is no characters to read you get -1).

else if(bluetooth.read()=='A'||'B'||'C'||'D'||'E'||'F');

Read another character and compare it to 'A'. This if is true if the character read is A. It also succeeds if B, or if C or if D, etc. That's not "if it's equal to C", just "if C". C is a character literal, so it's equivalent to a number. Any number that is not 0 is TRUE, therefore it's equivalent to:

if character is A or TRUE or TRUE or TRUE...

Which of course is just true, so it will always succeed regardless.

char myval= bluetooth.read();
if(myval== 'A')

Read yet another character from bluetooth (I sure hope there are enough there...) then compare it to a list of characters that are the same as you looked at above. You're comparing a new character this time, not the one you compared with the list a few lines beforehand.

• Anita B: Would the changes I made do any help?. I want my code to execute first if loop if the bluetooth sends a value between 1000 and 1360 and second if loop if it sends character A or D.@Majenko
• Majenko: Well, no. Because you can never read a character that is greater than 255 since such a thing doesn't exist. You need to read some tutorials on using serial on the Arduino.
• Anita B: What if I add a buffer?Can I then send values more than 255?and then compare value in the buffer@Majenko
• Majenko: There are a number of ways of transferring data using serial. Simplest is with an ASCII representation. Then yes, read characters into a buffer and use something like atoi to convert that buffer into a number.
• Anita B: Could you check this code please?@Majenko