Ouch. The Arduino GSM shield has a pretty serious design flaw,
with its capacitors.  Tantalum is a really misunderstood
capacitor. Well, all capacitors are misunderstood, but that’s a
subject for another post. I ran across this post on the Arduino
forums on the Arduino GSM shield. In the post, ddewaele, reports
that the shield blew up, catching fire. At first some might
think it was due to abuse by the user. While it is possible that
reversing the polarity or applying over-voltage could cause a
catastrophic failure, it is also possible that the user doing
nothing wrong could result in the same failure mode!  Wait,
what? So what gives? Well, there’s two things to understand.
First, Tantalum doesn’t explode. It takes almost 2000°C before
Tantalum metal will ignite. Okay, so if Tantalum doesn’t explode
what is ddawaele seeing? It’s the cathode material, Manganese
Dioxide, (MnO2) that is exploding…  Why don’t capacitor
manufacturers fix the problem?  If you buy capacitors from any
Tier 1 supplier (aka, not some n