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James Lewis

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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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Annotated Arduino UNO

westfw of the Arduino Forums has put together a nice Flickr Annotation of the New Arduino UNO. A couple of changes have been made from the previous Duemilanove. Interestingly they have left pads for either a crystal or resonator on the board. This may allow the end-user to use a crystal for more accuracy without adding additional cost for everyone else.

 

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8x6 Matrix Shield

Matrix LED Shield PCB

The PCB for my very first Arduino shield arrived today from BatchPCB. At first glance everything looks good. The silkscreen with my name and web address didn’t come out so well but that was probably my fault on trying to fit in too much.

Looking forward to assembling then with some Blue LEDs!

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EW: True Random Numbers from a handful of gates


Random numbers are a relative concept. In general, random numbers used in digital electronics are called Psuedo-Random sequences. There is a defined algorithm that is used to generate the sequence and does not actually occur in nature. In applications like Flashing a LED, this method is fine. However, for any level of encryption this is unacceptable.

Steve Buch at Electronics Weekly writes about how researchers Dr. Marie O’Neill and Dr. Jiang Wu at the University’s Institute of Electronics and Communications Information Technology (ECIT) has developed methods to generate true random bits digitally.

Fundamental to all of the ECIT generators is the effect of random noise during the transition from a metastable state to a bistable state.

Whether the output becomes a 0 or 1 depends on conditions, including internal noise, at the instant of input transition.

If you are giving thoughts to creating a cryptographic device, you might want to give their methods a look.

 

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Inside the iPhone 4 Gyroscope

One of the major feature updates for the iPhone 4 included a gyroscope.  There are two applications that a gyroscope can be used for:  keeping an object in balance and providing precise positioning data.  Obviously, the intended application in an iPhone is improved positioning and control of software objects.  One of the questions I had about the iPhone 4 was whether there was something (very tiny) spinning inside of the iPhone or if the device was solid state.  Until now, I had no idea that solid state gyroscopes existed.  Engineers at iFixIt, with help from Chipworks‘s Electron Microscope, have done a teardown of the iPhone 4’s MEMS based Gyroscope.

The pictures and lessons on how Gyroscopes work is fascinating.  Their article not only educates on how Gyroscopes work, but compare a spinning gyroscope to a MEMS based gyroscope.  The summary is, the iPhone and compact mobile devices like it, are packing some of the highest levels of technology we have on our planet.  Think about that the next time you are sending someone “just a txt.”

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