"LEDs are the most basic output device of modren electronics.They are very inexpensive and trivially easy to control from a microcontroller.They also come in a large number of different forms,including numeric and alphanumeric displays that provide a significant amount of information.They are very useful as tool for outputting status information from the robot to the user.I generally try to put LEDs on my input sensors.They can be used to light when there is a collision or indicates what a light level is.
Electrically,LEDs have some properties that you should be aware of first and fore most, they are diodes,which means that current in them flows in only one direction.Most modern LEDs require just 5 mAs to light,although there are some(especially high-output)LEDs that require up to 20 mA.
To connect an LED to a micro controller,it is Good practice to connect the anode to +5 volts, the cathod to a current limiting resistor,and the current limiting resistor to the I/O pin of the controller."
Demonstrate code in this sample output device that can independently control up to three LEDs.The Basic circuit is similar to the one used by ledflash, But has two more LEDs wired to RB2 and RB3,respectively (hopefully you haven't disassembled the led-flash circuit yet).The circuit diagram is shown in figure .
As LED technology continues developing and shows advantages of low consumption, long life-span and environmental protection, its application has shifted from initial indicator light to such more potential fields as display panels, illumination, backlight, automobile lights and traffic lights, etc.
This seminar will focus on the development and future outlook of current LED application market. It also profoundly analyzes 'hot' LED application markets including the display panel market, the backlight market, the landscape illumination market, the interior decorative lights market and the most potentially prosperous interior illumination market and elaborately studies the market scale, product structure, market configuration, brand fabric and market characteristics of LED.
George Lee, CEO of American Bright
B.S. in Physics: NCKU, graduated in 1984
M.S. in Physics: Sam Houston State Univ. 1987-1989
M.E. (Master of Engineering) in Electrical Engineering: Texas A&M Univ., 1989-1992
-Founded American Bright Optoelectronics Corp. with a Taiwan-based LED company, Bright LED Electronics Corp. (TWSE 3031) in 1995. Customers of American Bright include Lexmark, Chamberlain Group, First Alert, Carling Switch, Honeywell, Sloan Valve.
-Founded AB Lighting, Inc. as a Solid State Lighting company in 2006