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Arduino Shield

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Arduino

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…

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8x6 Matrix Shield

8×6 LED Matrix Shield for Ardiuno

This is a quick video demonstrating the LED Matrix Shield for the Arduino.  This Matrix is an 8×6 “Normal” matrix.  (It is not Chairleplexed.)  Blue LEDs were used to give it a brilliant hue and to provide another source of light in dimly lit apartment homes.  Only one row of the Matrix is lit up at one time.  This is done to save power and because the ATMega processor of the Arduino cannot source or sink more than 200mA of current.

Update 10/6/2012:  Project page now available.

The scrolling message can be any string of characters between ASCII 32 and 255. The font is a 8×6 font based on 5×7 characters.  Click below to see a picture of the Shield sitting on top of an Arduino.

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