Around The Web

LED Calculator

Parallel LED Circuit (with Resistors)

Rob ‘linear’ Arnold has put together a fantastic LED Series/Parallel Wizard.  Not only will it calculate the current limiting resistor you need, it will draw a circuit diagram, and give you full statistics on power usage.  If you are just getting started with Electronics, this is a great resource for learning about LEDs.  Experienced users will enjoy a quick check of their math.

The array above is designed for some Blue LEDs I have laying around.  I wanted them to run with 15mA which is well below their max, but still very bright.  In this case 1/4W resistors should be fine and each should be 120 ohms.  I should be safe hooking this array up to an Arduino since each LED will draw less than each I/O pin can handle AND total current draw is only 60mA.

Very Cool Stuff!

http://led.linear1.org/led.wiz

Read More
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.

Read More
Around The Web

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.

 

Read More