I like the color and the concept! I like what you did with your clock.

I have a noisy standard analog arm clock that is begging for some modern LED action!

 Sorry that you did not get any responses. So many posts, so little time. You are on the right track. You have got a project to work that is practical and useful! You have also did a good job sharing your code and you provide a picture. I applaud your work and appreciate that you shared it!

 Don't worry to much about responses, they do not always represent the majority of people's opinions.

That "quadcopter" seems to have 6 propellers.

 I should have known better than to slip that past you. 

 I fixed the title and post.

 The top level of motorcycle racing, MotoGP is in Texas this weekend. In the link below is a picture of a Hex-copter being used to take pictures.

http://www.superbikeplanet.com/image/2013/motogp/cotamarch/thegreatwondell/x.htm

Code:

if ((da == 0) && (db == 0)||(da >=10) && (db >=10))

Don't forget TWO == signs when doing a check with an "if" statement.

One = sign is used for setting a variable to a value.

 You could add a "or' ||, to add another check. This would say if either number is NOT = 0 and is not greater than 10....go straight.

  Lots of details from your set-up are missing. You should list things like:
the code
the Arduino board
Relay board link or datasheet
power source / sources
type of load on relays
Anything that may be related to your problems.

 Put "0" in the integer postions of this "if" statement.

Code:

if ((da >=10) && (db >=10))
{
 
digitalWrite(lp, HIGH);
digitalWrite(ln, LOW);
digitalWrite(rp, HIGH);
digitalWrite(rn, LOW);
Serial.println(" go straight");
Serial.println(da);
Serial.println(db);
}

If the either sensor output results as "0" you will not go straight.

 Each movement decision is based on an "if" statement similar to this:

Code:

if ((da <=10) && (db >=10)

 I recommend printing "da = " da ........and print "db = " db....... this will show what those numbers are and if they are changing. There must be a problem related to those two number results.

 It is nice to see all the work being put to this screen! Thanks!

[Latest information posted on the above links:]

@Ashton, I am not a member of their club but, I have made it to a few meetings. I might be able to help you if you have a specific question. However, for the moment refer to the information below.

 It looks like they change their location for meetings. I haven't been able to make a meet in some time. I hope to go to another meet in April.

Latest information posted on the above links:
Our club meetings are held the first Saturday of each month, from 10:00am to 1:00pm at the St. Louis Science Center. Bring your project (in any state of completion) for show and tell or to ask for help. Click on the calendar events on the left side of this page for meeting details.

Meeting location:
Saint Louis Science Center
5050 Oakland Avenue
St. Louis, MO 63110

Link to their forum:
http://www.robomo.com/smf/

@CyklKent

 I have seen some videos where people have put tubing, or short pipe over each half of the sensor. The result looked like binoculars. I think the reason was to make a the sensor's "vision" narrower and allow the sensor to only focus on a smaller area.

  Like my last two cars...worn out engine, used-up tires, a few minor dents/scrapes, and a load of memories.

 @sisyph

 I recommend you share your code that you are using, just to eliminate the possibility of the code being the problem.

Where did you initialise serial data speed on Bluetooth device?

Between the Bluetooth device and the phone, the serial data speed is solved during "pairing" of the device to the phone. At least this is my belief.

  Nice to know your board still has a chance to live! Sounds like it is going to have nearly anything a person could possibly want!