Sunday, March 13, 2011

My iPhone Sensor Issue SOLVED !!!!

YES FOLKS!  I've finally solved the iPhone "blink on, blink off" sensor issue!  After months of tinkering and meandering with thoughts of software vs. hardware issues (see previous posts 1 and 2 ), it turns out that the blinking issue has nothing to do with Apple.  At least not in this case.

To recap, the issue at hand is the appearance of a blank black screen during a phone call.  This would make it nearly impossible to press the virtual speaker button or hit the vitrual keypad during phone calls.  Over time, I felt that this was a software issue after playing around with mockups created with my Arduino electronics kit at home and listening to Steve Jobs give an interview last summer, prompting me to write about this in a previous post.  I then thought that if the various updates of iOS 4.0 to the present 4.3 couldn't resolve the issue, then it may have been a bad batch of iPhones, relegating this to being a hardware issue.

Now I am not saying that this is the solution for everyone, because it may not be, but I began to notice some strange things as to when the "blackouts" would occur with the phone.  It almost never happened in a darkened room, only in broad daylight or a well lit room.  But the only thing that I could muster from all of that was that it was a sensor issue.  If I kept the "Home" button pressed it would keep the screen on, but that would also do some other unpredictable things.  If I covered the sensor it would do the obvious - create a blank screen.

In retrospect not much had changed in my usage habits from my iPhone 3G to my iPhone 4.  I became a creature of habit, spending a hefty sum of $45 for a leather Sena case for my iPhone 3G.  It was a perfect case that had a very nice clip that would hitch on to my belt with its attachment.  It was a flip case made of soft leather.   I did not want to get rid of it, so when the iPhone 4 came out, I was saddened to see that it would not fit perfectly.  But I found that if I added an old Driver's license and a workout club card in the back, the iPhone 4 fit perfectly in place.  The sensor was wide open, the ear piece was also wide open.  Everything was perfect.  Or so I thought !

I never used the phone out of the case.  As I said, I became a creature of habit.  I was always thinking about donating the phone or reselling the phone later to somewhere such as   and I wanted the phone to be in pristine shape when it came time to do so.  So when I visited the Apple store 3 weeks ago, after upgrading the software twice, I approached the Genius Bar expecting nothing but the company line or a test of the phone and the possibility of a new phone replacement.  The Genius Bar employee looked at my phone and asked me to try a phone call to see if it would happen again.  Since the Apple Store is brightly lit, the flaw would be easy to reproduce.  Like clockwork, I made a phone call and the screen went black.  He then asked the simplest question, "Have you ever tried using your phone outside of that case?"  Your kidding right?  Come on!  No Way!  I looked at him with chagrin, and of course I had to say "No!" I then proceeded to take the phone out of the secure leather case and dialed 611.  No vanishing screen.  A perfect phone.  Refusing to believe that this was the case, I then proceeded to make no less than a dozen calls without the case.  My naked iPhone streaked across the airwaves with ne'er a blip on its screen.   I thanked the Genius Bar employee a thousand times, but I have to admit that I had a tough time looking him in the face.  I was really ashamed of the fact that I thought that I could cheaply just switch out my old iPhone with a new one and not have any problems.  I even blogged about the issue vociferously.  I WAS WRONG !!!!

I am now in the process of looking for a new case, but I have made phone calls with my phone in all sorts of lighting conditions and the problem of the sensor has not reoccurred.  What is interesting to note in hindsight is the fact that the lighting had a lot to do with this issue.  As my Genius Bar employee hypothesized, the issue at hand was that the black leather, which was not fully adhered to the phone at the top was casting a shadow over the sensor and the sensor was reading this as skin contact or a darkening of the light and hence it would trigger the screen to go blank.   What a welcome solution.

So there you have it.  In this case at least, using a non-sanctioned iPhone 4 case can lead to sensor problems.  I hope you enjoyed reading my quest for a solution to this problem.  If you have any other suggestions please feel free to post in the comments.


  1. It's funny you consider a non-blank screen to be a normal functional phone. My phone no longer goes blank when I hold the phone to me ear causing it to mute/hang up/hold/speaker/dial random people in the middle of calles -- I consider that broken. I WISH my phone would go blank when I make calls. Maybe your face doesn't push buttons when the phone malfunctions.

    1. Thank God! I thought it was my isolated issue.

  2. It sounds as if you may have a faulty sensor. In my case, I did silly things such as look at code written for assessing light input and other silly things before finding out that it was my "cheapness - not buying a new case" and using the iPhone 3G case that was the problem all along.

    My phone works perfectly now and I too had the problem of face activating apps, but no longer, that's why the screen is supposed to go blank when it reaches your head. It's a great product with a lot of thought going into the tiniest things. When it works, it is brilliant.

    Hope you get to fix the maladies of your phone. By the way, I ran into a site that may interest you called (no this is not a spam message). I have noted that there are quite a few people willing to swap their iPhones for something else. Right now I would recommend buying a phone on the secondary market with the iPhone 5 being just a few months away.

    Again, thanks for writing and for reading my blog.


I will be trying unmoderated comments for a while. If this gets ridiculous, then I will have to move to moderating the comments once again.