We incorporated among standard stock types the dot matrix LED display Kingbright TC12-11 with the height of 30.6mm. Hyper red color (630nm) and a high luminous intensity provide a contrast image.
TC12-11SRWA with 5×7 dots can be conveniently used especially in indoor applications, where it will provide an excellent readability at various ambient light conditions. Display can also be used for outdoor applications, excluding places on a direct sunlight, where the display legibility can be substantially decreased.
High light output, typically 82mCd/10mA and white diffused lens ensure a very good visibility even from higher viewing angles. Display features almost a linear luminous intensity / current characteristics in a range from 0 to 20mA, that´s why it is fully usable even for low power applications. Similarly like almost all dot matrix displays, even TC12-11 is designed in a way that when placed in a row, we will obtain a continuous row with homogenous spacing between dots. That´s why it is possible to display even symbols wider than 5 points and naturally a moving text.
TC12-11 has a common cathode (in a column), available are also versions with a common anode (in a row) and also various colour versions.
Universal 1.2″ LED dot matrix display - [Link]
Seven segment LED displays are a very popular mean of displaying numerical information and finds application in front panel display boards of microwave ovens, washers and dryers, digital clocks, frequency counters, and many other gadgets. Compared to the LCD displays, the seven segment LED displays are brighter and provide a far viewing distance and a wide viewing angle. However, the downside is they are resource-hungry. It requires at least 12 I/O pins of a microcontroller to drive a standard 4-digit seven segment LED module. Consequently, their use with low pin-count microcontrollers (such as PIC12F series) is not practically feasible. Here’s a solution for that. The following 4-digit seven segment LED module features a serial interface that requires only 3 I/O pins of a microcontroller and provides full control of all digits and decimal points .
Serial four digit 7-segment LED display module - [Link]
The Binary Burst clock shows the time with LEDs:
The clock uses 3 LEDs on each spire to count up to 5 in binary. The hours are displayed by the middle LED in RED (Its a Red/Blue bicolor, the others are just blue). Video, and links to the board and code repository are included in the post. Check out a demonstration video below. There’s also a time-lapse soldering video of build. [via]
Binary Burst clock ticks away the time with LEDs - [Link]
A CREE MCE4-LED mounted on a STAR PCB. Available in cold white, warm white and RGBW versions, can be powered by a constant current of up to 700 mA – 430 lm
A CREE XP-G LED mounted on a STAR PCB. Available in three shades of white and powered by a constant current up to 1050 mA. Matching lenses of 7°, 15.5° or 25° beam angle are available as accessories.
Giorgos Lazaridis writes:
Some time ago i published a theory page regarding the LED driving and controlling methods. These methods were all linear regulators, very simple to make but very inefficient -in terms of power consumption- for high current applications. The idea was to use this theory page as an entrance level for the SMPS LED drivers.
The first SMPS (Switching Mode Power Supply) LED driver that i made is a Buck-Regulating LED Driver using a chip from Allegro Microsystems, the A6210. I was provided some samples from Farnell for testing and prototyping, along with some other cool staff. Do not forget to pay a visit to Farnell on-line store and Element14 website.
The A6210 can drive up to 3A load with constant current, with switching frequencies up to 2 MHz and supply voltage from 9 to 46 volts. It has additionally an optional PWM input to control the brightness of the LED. The sense voltage is limited to 0.18 volts for higher efficiency, since the power dissipation on this sense resistor is minimal. I will be using a 10-12V 1A 10 Watt LED, powered from 24 VDC supply.
High Efficiency High Current LED Buck Driver using the A6210 - [Link]
Giorgos Lazaridis writes:
The idea for this project came from Viktor’s site, a guy that has some interesting projects in his DIY subdirectory. He cloned a HDD spindicator with 10 LEDs driven from a 4017 chip. I liked the idea but the implementation was kinda… sterilized. So, i decided to make one for my PC, but spice it up with PWM control…
HDD LED Spindicator - [Link]
Isolated offline-flyback controller LT3799 enables to create a powerful LED driver with a minimum of external components, which is moreover compatible with common triac dimmers.
At the design of a new LED driver, we usually have to consider more factors like for example an output current stability, shortcut or open LED protection, efficiency, safety (isolated secondary circuit form the primary one), power factor correction, EMI, number of external components and other.
LT3799 meets all these requirements and offers another benefits, like for example a possibility to use a smaller transformer thanks to the use of critical conductivity mode, powerful external MOSFET driver, internal LDO regulator and also a very good output current regulation – typically +-5%, moreover with no opto-isolator. A big bonus is the active power factor correction, thanks to which it reaches typical values of 0,96 (at 230V AC), thus meeting the most stringent requirements in this field, as well as IEC 61000-3-2 class C about harmonic currents emission. When we look closer at the recommended application circuit, we´ll find out that behind a diode bridge we won´t find any (otherwise common) input electrolytic capacitor with value of tens or hundreds of uF. That´s why the input voltage of the controller and a of the power transformer “copies” input sinusoid. Excellent power factor is reached just thanks to it, that LT3799 knows immediate input voltage value and based on this value, it sets the input current limit (in a given cycle of the SMPS), proportionally to the immediate value of the input AC voltage. Further LT3799 gains information about the immediate current from the primary side, that´s why it doesn´t require an opto-coupler. Thanks to this, LT3799 works like a current source in every period of input voltage, that´s why it is even possible to use classic triac regulators, which are often already a part of the buildings installation. In other words – LT3799 doesn´t try to compensate “dropouts” in power supply caused by a phase control of a triac, what causes decreasing of an output LED current and their fluent dimming. Neither this control method doesn´t cause LED blinking, because there is an electrolytic capacitor on the transformer output.
LT3799 – create a LED driver with an active PFC - [Link]
Tenty LED Brake Lights. Pete writes – [via]
I Purchased a motorcycle about two weeks ago. Interestingly, whenever I tell someone this news, they immediately proceed to tell me the most gruesome injuries and stomach turning plights that they or someone they know, has fallen victim to while motorcycling. In some cases, these raconteur’s briefly pause to look over their shoulder, presumably scanning for small children or otherwise offendable ears, before delivering the goriest details.
One commonality in these stories, aside from the macabre and arguably poor timing involved in telling them to me is that many accidents come down to a lack of visibility of motorcycles and their riders. Less than Argus-eyed motorists often pull out into the path of a motorcycle and with insufficient time for evasive action, that quickly an accident has occurred. Other times, drivers may focus on the car ahead of the motorcycle and in the event of stopping at a red light or similar, fail to leave enough room.
Tenty LED Brake Lights - [Link]
Richard Comerford writes:
More than ever, cameras are becoming a part of the personal and business devices we carry in our pockets. While the light levels at which today’s photographic image sensors can work is extremely low, having flash lighting means users can capture greater detail at faster speeds. And to be sure that flash systems do not consume a lot of the power budget of these battery-run portable electronics, designers have turned to using LEDs as the light source, rather than the traditional xenon tube.
A broad array of devices is available today for driving LEDs as flash devices. Many can deliver high current so that LEDs can be driven to maximum output. However, the increased efficacy of today’s LEDs – meaning they can deliver more light from less current – means that drivers can also focus on reducing current drain on batteries.
Five Solutions for Driving LED Flash in Mobile Devices - [Link]