Tag Archives: LED

App note: Understanding and preventing LED Failure

When using LEDs in projects it’s good to know what could cause their failure, and design your device to prevent it: LEDs have a well-deserved reputation for high-efficiency operation, not to mention high reliability. Properly specified and implemented, LEDs should and do satisfy virtually every lighting application. Still, there are times when actual device lifetimes […]

App note: Implementing bidirectional interface with a single common LED

Here is an app note from Mitsubishi Electric Research Laboratories describing how to implement short-range low-bandwidth bidirectional communication using common LEDs. It’s called LEDComm and requires only two pins of a microcontroller and a current limiting resistor to function. It works by making use of the fact that LEDs, once reverse biased, are also pretty […]

PixelInvaders: LED matrix panel

Michu built a LED matrix panel that is controlled by his PixelController software we blogged about. The panel consists of 64 individual RGB modules. The modules have three RGB LEDs on them controlled with a LPD6803 serial shift register LED driver. The color range is 15bit deep, or 5bit per basic color. By connecting them […]

Driving a bicolor LED from a single output pin

This blog demonstrates how to drive a bi-color LED, or any 2 LEDs, by using only one microcontroller pin. Sinking or sourcing current from the LED selects which one will light up. Setting the pin as input turns both LEDs off. Alternating between 0,1, and high-Z, both LEDs are fully controllable and even dimmable. The […]

7400 competition entry: Bad driver feedback display

Gagandeep built a “bad driver” feedback display. It’s a huge 40X16 LED matrix spanning ~80cm in width, and it’s designed to be placed on the rear windshield of a car. The spacing of 2cm between LEDs is enough to ensure that the driver doesn’t have an obstructed rear view. Using 2 74HC595 8bit serial in […]

App note: Driving LEDs in battery-operated applications

Driving many LEDs from a battery can be a pain to do, especially if you need many of them to have the same brightness. One way to do this is to use current mirrors for each individual LED, and drive them from the battery voltage only. Another is to drive them with a dc-dc boost converter in […]

2A automotive step-down converter

rsdio writes:  maybe voidptr can use this in his Noob car blinking LED project… MAX16974 High-Voltage, 2.2MHz, 2A Automotive Step-Down Converter with Low Operating Current Wide input voltage range (3.5V to 45V) allows seamless operation from cold crank to load dump Low quiescent current meets tight power budgets High-frequency operation eliminates AM-band radio interference

ATmega168A pulse width modulation (PWM)

ProtoStack shows how to dim a LED using pulse width modulation and an ATmega168A: Dimming an incandescent bulb is easy. Simply adjust the current down using a potentiometer and you are done. Dimming an LED is another story entirely. When you reduce current through an LED there are unintended consequences like color shifts and dropouts. […]

App note: very low-cost sensing and communication using bidirectional LEDs

Squonk writes Here is an interesting paper on “Very Low-Cost Sensing and Communication Using Bidirectional LEDs”. Not new (2003), but this technical report is very detailed. The abstract to the document by Mitsubishi Electric states: “A novel microprocessor interface circuit is described which can alternately emit and detect light using only an LED, two digital […]

Week in (p)review: February 13, 2011

Don’t forget to share your current project in the comments or the forum. This week our favorite project gets a free SOIC protoboard. Here’s a summary of major developments over the last week: Jawi released a new version of his client for the Logic Sniffer. This supports new features in the experimental Verilog core from […]

Week in (p)review: February 06, 2011

Don’t forget to share your current project in the comments or the forum. This week our favorite project gets a free SOIC protoboard. Here’s a summary of major developments over the last week: We released a bunch of abandoned or stalled prototypes: XT IDE disk controller, Ethernet JTAG debugger, Ethernet LED driver, PIC Z-machine emulator, […]

3D LED cube thing

MichaelZ spotted a commercial 3D LED cube. I saw this at a home construction materials show in Taiwan 3D LED cube thing  In person they are very impressive.  There are vertical strips of SMD LEDs and the light changes color.  Amongst patterns they can sort of swirl around like a cloud or school of fish. […]