Tag Archives: Led(s)

App note: Preventing LED failures caused by corrosive material

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Chemical compatibility of LEDs application note from OSRAM. Link here (PDF)

The performance and stability of light emitting diodes (LEDs) may be influenced by various chemical incompatibilities arising from chemicals and materials used, amongst other things, in luminaire construction, or by gases in the proximate environment of LEDs during field operation. Nevertheless, LEDs have to fulfill a wide range of customer needs and requirements in indoor and outdoor applications.

This application note provides information about the chemical compatibility of certain substances with LEDs, particularly with regard to some of their basic components. In this context, the main mechanisms of chemical incompatibility are illustrated using examples of blue and white LEDs.

App note: Advanced LED rework procedure for video wall and signage applications

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App note from OSRAM about LED rework on signages and their demand for more sophosticated tools. Link here (PDF)

SMT LEDs have became more and more popular in video wall and signage applications, replacing radial LEDs. This leads to more difficulties during the repair or replacement of failed LEDs on PCBs, especially for QFN (Quad Flat No-lead) packages, as there is no exposed lead. This application note provides basic information on how to rework the SMT LEDs in video wall and signage applications. To describe the rework process the DISPLIX Oval LED was chosen an example, as the rework of this LED is more challenging due to the lack of exposed lead and the oval lens on top. However, the procedure is also suitable for other LEDs. In this application note details on the materials used, examples of suitable equipment and the process are presented and described. Finally, the test results of the LED after the rework process are presented, showing that in this case the rework procedure did not cause any damage to the LED itself.

App note: Matrix LED and where they are used

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White paper about matrix LED usage from Integrated Silicon Solution Inc. (ISSI). Link here (PDF)

People today come in contact with a wide range of consumer electronics (CE) devices in their daily lives. CE devices have become increasingly complex with added functionality enabled by MCU’s which provide the intelligence for automating functions. Control panels used in appliances and other equipment leverage MCUs and several integrated circuits to enable functions, such as sensing, process control and user interface (UI).

The user interface consists of input controls, visual and audio feedback used to configure the product to perform complex tasks. An aesthetically pleasing UI is a major differentiating feature for home appliances such as ovens, washing machines and refrigerators. Home appliance UIs commonly use capacitive or inductive touch sensing to provide an easy to clean interface unmatched by mechanical buttons. In addition to touch sensing, a UI has to provide audio and visual feedback in response to the user selection. The UI may not be the most important factor in determining the commercial success of CE devices. However, once parity is established on the major functions such as washing capacity, energy efficiency, etc, the UI becomes a key differentiator. Today, parity has been established on most of the important factors making the UI a product differentiating factor.

As the trend continues to move away from purely mechanical switches to a fully electronic interface expect to see demand for LEDs and drivers to continue increasing.

Lightronome 1 – The light based metronome

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Lightronome

Zoltán Gomori documented his lightronome build:

I got a request, to design and build an electronic metronome. You can find several on the market, but the problem it is ether producing voice or the classical mechanical metronome. The requirement here was a visual effect. To be precise four LEDs for 4/4 beat. It is required for drumming where you have no chance to hear the clicking (or maybe just through headphones).

See the full post on PakaHuszar blog.

Check out the video after the break.

STM32F103 vs GD32F103 round 2: Blink a LED

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A follow-up to the STM32F103 vs GD32F103 round 1- Solderability post, Sjaak writes:

The defacto ‘hello world’ for microcontrollers is blink a LED at a steady rate. This is exactly what I’m going to do today. I made a small 5×5 development board, soldered it up and started programming. In this first example we not gonna use fancy IRQs or timers to blink at a steady rate, but we insert NOPsas delay. This would give an idea of the RAW performance of the chip. The used code is simple; set up the maximum available clock available and then toggle RA0 for ever.

More details at smdprutser.nl.