Exit Review: The Samsung Galaxy S-II
Noted hardware hacker Bunnie Huang looks back at two years with his Samsung Galaxy S-II cell phone. How did this gadget survive two years of international travel?
Andrew “Bunnie” Huang is a legend in the hacking and open source worlds. While studying at MIT, he literally wrote the book on reverse-engineering the XBox game console. Subsequently, he worked on the ill-fated Chumby project and has been working on a number of open source hardware projects, including an open source geiger counter called the Safecast geiger counter that anyone can build and use. This project arose in the wake of the 2011 Japanese earthquake and release of radiation at the Fukushima nuclear power station. People were scrambling to find ways to measure the radiation level, so Bunnie helped to design an open source geiger counter that anyone could build cheaply. The Safecast project now collects and shares radiation data from around the world, so anyone can find their local radiation level, and watch the impact of nuclear accidents. He has also worked on silicon photonics at Luxtera, and was awarded the EFF Pioneer Award in 2012.
Currently, Bunnie is working on a project called Novena, an open source laptop that anyone can build to run open source operating systems and software. He also regularly tears apart and analyzes products on this blog, like a $12 cell phone that he purchased in China, and has produced a course that teaches students how to work with Chinese manufacturers, from creating a bill of materials to picking a factory to work with. So, when this designer and builder of gadgets offered us the chance to publish one of his articles, we jumped at it. Here, he examines the cell phone he has been using for two years to see how it stood up to the punishment of this jet-setting tech maven: the Samsung Galaxy S-II.
Consumers tend to throw away old gadgets with little fanfare or thought. I think that’s a shame; all the knowledge and experience gained navigating the quirks of the old gadget are tossed as well. Thus, instead of raving about the latest greatest gadget, I like to jot down a few notes about my old gadgets when I retire them.
The Samsung Galaxy S-II was my first Android phone. Prior to the Galaxy, I was a devout Blackberry user, but with the release of Blackberry OS version 6, the Blackberry platform lost its greatest single selling point to me – rock-solid reliability. For me, first and foremost a phone must be reliable: it is unacceptable to give the excuse to a coworker, client, friend or family that I was unable to come to their aid because my phone had crashed, or run out of battery. So, when my Blackberry Torch started locking up on me all the time and failed to retrieve email reliably, I…well, torched it.
Fortunately, in Singapore it’s easy to do a soft-transition to a new phone platform, as all phones are unlocked and phone plans are tied to a transferable SIM card. At the time, I had a team of developers working for me, writing Android and iOS apps, and after observing the capabilities of the two platforms from the developer perspective, it was clear that Android would be the best fit for my needs. The relative openness of the platform, and the diversity of the available hardware appealed to me.
At the time, the S-II was the flagship Android platform, so I picked one up. Overall, I’d have to say my experience has been positive, as I’m now on my second Android phone.
I’m extremely tough on my phones, and I don’t believe in putting them in “condoms”, as I refer to the rubbery silicone sleeves that seem to inevitably adorn iPhones – it’s not hyperbole to say that the iPhone4 is made out of glass.
While the S-II didn’t win a lot of style points for its design, it survived a year and a half of hard use. The phone endured being dropped on concrete, sat on, fallen on, dropped in a sink, and so forth. Looking at the overview photo of the front, it’s hard to guess what the phone had been through.
A careful inspection of the phone reveals a few scars with stories behind them. The screen has one tiny chip on the edge, evidence of a fall from my pocket onto concrete.
Overall, the screen and touchscreen of the phone performed admirably. The OLED display was crisp and sharp, and more than one iPhone user had commented enviously of its color depth and viewing angle. My only complaint about the screen in the end was that its resolution wasn’t high enough, as I like to pack a lot of text into my screen when I read emails.
The “butt” of the phone – the area to the right of the above photo – is just a couple millimeters thicker than the rest of the phone. While this design feature was maligned by reviewers with a severe case of gadget anorexia, I found it to be a saving grace. The slightly rise on one end meant that the phone does not lay flat on a table, preventing the phone from wicking up nearby beverage spills.
Overall, the biggest wear-related functional failure of the phone was the camera lens. The picture above doesn’t have the resolution to show it, but this lens is covered with hundreds of tiny scratches from impact with coins, keys, and other debris in my pockets. The problem is exacerbated by the fact that the lens protrudes slightly from the body of the case, which means it’s more likely to make incidental contact with various items near it in a pocket. The net result is that toward the end of my phone’s life, all photos started to develop a bit of a hazy glow.
Above is what the phone looks like with the back cover removed. The phone’s seal around the circuit board performed admirably; you can see plenty of dust and gunk around the snap-locks but none inside of them.
Above is a zoomed-in view of one part of the phone, showing the contrast of the gunky outside-facing seal and the relatively pristine inside.
The opposite side of the motherboard reveals that the circuit board itself also held together fairly well. The only signs of wear is a slight bit of water staining on one chip near the lower side of the board in the photo below.
From the internal functional standpoint, there were four major points of failure: the wifi reception, the microUSB connector, the GPS radio, and the battery. The wifi antenna connector is called out with the green arrow, and the microUSB connector with the red arrow.
The wifi performance of the S-II was never very good. Holding the lower part of the phone in your palm (a very natural thing to do) would cut wifi reception dramatically. There are understandably few places to cram an antenna into a phone so slim, so perhaps this was just the best compromise the engineers could make.
The elements pointed to by the green arrow are a type of component known as a “leaf spring” connector. It’s a small piece of metal bent over into a C-shape to make contact with an antenna PCB on the opposite half of the case. The contact is maintained solely through the spring force of the C-shaped piece of metal.
Above are the opposing contact points. As you can see, the leaf spring contacts had worn a couple of divots into the contact points. Also, the leaf springs themselves seem to be a pushed down a bit low to be making good contact. As a result, I suspect that the poor reception of the wifi may be due in part to a flaky contact between the antenna and the main PCB.
The second visible point of failure is the microUSB connector. This is a natural point of failure, as it received all told a couple thousand insert/eject cycles over the life of the phone, and also was exposed directly to the elements.
Above is a view of the microUSB connector through a microscope. You can see the greenish deposits of copper oxide, from where moisture had interacted with the copper underneath the gold plating. The human pocket is a hostile environment for metals like copper, as it is typically humid, warm, and somewhat salty. Eventually this corrosion contributed to an inability to reliably charge the phone; toward the end I had to fiddle with the angle of the microUSB cable to ensure good contact with the connector.
Above is the same connector, but with the focus of the microscope tuned a bit deeper. Here, you can see an intense collection of pocket lint, the result of thousands of cycles of compaction with a microUSB cable, ramming the lint into a solid cake of gunk at the base of the connector. Pretty gross, and amazing that it worked as well as it did.
A third point of failure, the GPS radio, isn’t possible to photograph. The phone’s GPS worked fairly well for the first few months, but over time it became harder and harder for it to get a lock. Near the end of the phone’s life, GPS diagnostic software revealed it was able to see plenty of satellites, but it wasn’t able to triangulate a position off of them. My best guess as to why this failure manifested is that the crystal used as the timing reference for the GPS radio suffered from mechanical shock damage.
I had a tendency to slap the phone on the palm of my hand – the phone had some spring-elements on the inside, and if you hit the phone just right on your palm you could feel it resonate with a bit of a “twang”. I don’t know why I liked to feel the twang of whatever it was on the inside, but it does mean that the phone received a lot of excess mechanical pounding as I tried to evoke the effect. Alas, mechanical shock is known to degrade the accuracy and performance of crystal oscillators, on which the GPS unit probably relied to get a lock on satellites. I had also noticed that if I had turned off time acquisition from the GSM system, the internal RTC of the phone drifted by minutes a day, another indication that some of the internal crystals were being damaged from repeated shock. Moral: don’t smack your phone around for the fun of it.
Above is a picture of the ultimate culprit that forced the retirement of this phone. Well, actually, it’s a photo of a replacement for the original culprit; I was unable to keep the original battery due to restrictions on flying with spare batteries in luggage.
My original battery, after about a year and a half, started to develop a bit of a bulge in the middle. It’s fairly subtle, maybe just a half millimeter of bulge; I didn’t notice it, even looking edge-on. However, a battery vendor in China showed me a quick test to determine if a battery is failing in this manner: place the battery on a flat surface, and attempt to spin it. If it spins freely, then the middle is bulged out, and the battery is no good and should be replaced.
The first noticeable symptoms of the battery going was the phone would drop from about 30% charge to zero very suddenly, within about ten to twenty minutes. I had originally thought it was due to an errant app burning up the battery, but it happened too often and too regularly. I tried cleaning the battery contacts to see if that would fix the problem, but no dice.
Over a period of two months, the problem got progressively worse, dying at 40%, then 50%, and finally running for maybe 4-5 hours before dying. I was toting around a spare battery bank just to keep the phone functional all day. I knew I had to get a new battery, but I was busy and didn’t have time to go to the market.
Then it happened. One day, I was playing a video game on the phone (probably a bad idea when you know the battery is weak), and the screen started to dim and brighten wildly. I stopped playing the game, but unfortunately, the damage was already done. The phone rebooted itself, and the unstable battery voltage had corrupted the phone’s filesystem. This was totally my fault – I’m familiar with the ugly kinds of corruption that can happen to Flash memory when the power glitches, yet I kept on using my phone with a bum battery. When the phone came back up, it reported that the filesystem damage was unrecoverable and it had to perform a factory restore. Even that was unsuccessful; the phone could only partially restore its original factory image, rendering it unable to install or run apps.
For better or for worse, I was traveling to Tokyo the next day, and there I met up with Henry Holtzman, a specialist in consumer electronics from the MIT Media Lab. I told him about what I liked and didn’t like about the Samsung S-II, and he recommended that I get the Samsung Note-II. I originally thought I would hate the chunky phablet form factor, but in fact Henry was dead-accurate in the recommendation. I love my new Note-II, and I hope that I won’t have to do an exit interview on it for at least a couple of years.