Led category

Wooden Digital Clock is controlled over WiFi

androkavo @ instructables.com build a nice looking wooden clock that is able to show time, temperature, humidity and also it has alarm. The clock is controlled through your web browser using wifi connectivity and it also has a vibration sensor to stop the alarm.

Wooden Digital Clock is controlled over WiFi – [Link]

Sound Activated LED Light With Timer

Clap to light switch with timer project is very useful project for power saving applications. The project switches on the LED light for 45 to 60 seconds when receives two clap sound. This project can be used in store room, toilets, dark area where switch is not visible, night lamp, places where light on off switch is not accessible easily.

Single transistor used as microphone preamplifier, diode converts AC signal in to DC , and PIC micro-controller take care of LED On/OFF Time, LED  time depends on two jumpers J1, J2 which provides four options s 45, 50, 55, 60 seconds. MJE3055 transistor used in output to drive LED, one series resistor R10 helps to control the current going through LED, R10 can be alter as per LED Voltage and current. 3V to 12V LED with maximum current 500mA can be used. Use higher current Darlington transistor like TIP147 for higher current Load. Onboard potentiometer trimmer for sound sensitivity adjust. D1 power LED.

Sound Activated LED Light With Timer – [Link]

PICTIL – Remake of the TIL311 hex LED display

Yann Guidon @ hackaday.io rebuild the TIL311 hexadecimal display using a pic microcontroller. He writes:

The TIL311 is a nice but expensive, obsolete, power-hungry hexadecimal display. It would be cool to make a tiny module with similar functionality which solves its shortcomings. A 20-pins PIC is a solution but other decoding chips could work too. The PIC16F527 is one of the cheapest 20-pins PICs (sub-dollar), but it can’t implement the latch pin as fast as the original TIL311.

PICTIL – Remake of the TIL311 hex LED display – [Link]

Programmable LED dimmer

A Programmable LED dimmer from Soldernerd:

Around one and a half years ago I’ve designed and built various LED dimmers for both white and RGB LEDs. Then late last year someone approached me asking if I could make an RGB dimmer for him, too. But my designs were really tailored to their specific applications and built with home-made, i.e. milled PCBs which are time-consuming to make. So I decided to make a more universal version based on a proper, etched board which could be built in a small series and used for all kind of applications, both white and RGB. The result is this versatile, programmable 4-channel dimmer.

Programmable LED dimmer – [Link]


Multi-brightness LED controller draws zero off-current

T A Babu @ edn.com has a design idea of a led controller with some nice features:

The key features of this Design Idea are:

Soft switch on/off operation

Zero current drain in sleep mode

Two level dimming

Low battery protection

Simple controller based on CMOS 4017 Johnson counter

Multi-brightness LED controller draws zero off-current – [Link]

50 Segment Serial Bar-Graph Display Driver

The serial controlled 50 Segment Bar-Graph Display built using CAT4016 IC. Very useful projects for development Bar-Graph based, Temperature Meter, Interactive Games, Voltage Display, Current Display., Pressure Sensor, Magnetic field meter and PH Meter. Tilt meter, LUX meter.

The CAT4016 is a 16 channel constant current driver for LED billboard and other general display applications. LED channel currents are programmed together via an external RSET resistor. Low output voltage operation on the LED channels as low as 0.4 V (for 2 to 100 mA LED current) allows for more power efficient designs. A high−speed 4−wire serial interface of up to 25 MHz clock frequency controls each individual channel using a shift register and latch configuration.

50 Segment Serial Bar-Graph Display Driver – [Link]

Add OLED Display To Your Projects With TeensyView

The Teensy is a complete USB-based microcontroller development system, in a very small footprint, capable of implementing many types of projects. All programming is done via the USB port. You can program for the Teensy in your favorite program editor using C or you can install the Teensyduino add-on for the Arduino IDE and write Arduino sketches for Teensy.

The processor on the Teensy also has access to the USB and can emulate any kind of USB device you need it to be, making it great for USB-MIDI and other HID projects. The 32 bit processor brings a few other features to the table as well, such as multiple channels of Direct Memory Access, several high-resolution ADCs and even an I2S digital audio interface! you can learn more about Teensy by visiting this page.

SparkFun had launched a new add-on to Teensy that can make it possible to add to it display functions. The SparkFun TeensyView brings you an easy way to add a small, white-on-black OLED to your Teensy development board. The 128×32 monochrome display is controlled with the popular SSD1306 IC, and is a great way to display debug information and to visualize data without the need for a serial terminal. The board matches the Teensy 3 form factor perfectly, and was designed from the ground up to be as flexible as possible while still being able to nest down into a low-profile addition for the Teensy.

The TeensyView comes with everything you need except the headers. Additionally, there are jumpers on one side of the board that allow you to configure how the OLED communicates with the attached Teensy. Since this is a headerless board, you have the option to solder on whatever type of header best fits your needs. Headers you may find useful with this product include the Teensy Header Kit, Straight Headers, Long Straight Headers and Female Headers.

Teensy 3.2 is available at SparkFun for $19.95 and TeensyView is available for $14.95. TeensyView right now is out of stock but you can still follow up and get a notification once it returns to stock.

You can know more in-action details by checking this SparkFun tutorial and checking theses links SchematicEagle FilesDrawing BitmapsOLED Memory MapDatasheet (SSD1306), Arduino Library, and GitHub!

Source: SparkFun

Super Efficient Nano-LED

For the exponentially growing data traffic worldwide, the data connections within and between microchips are increasingly becoming a bottleneck. Optical connections are an obvious successor, but that requires an adequate nano-sized light source – and this has now been found. Researchers from the TU Eindhoven have succeeded in making a nano-LED with an efficiency 1000 times greater than its predecessors, and which can operate at a data rate of gigabits per second.

The data connections between microchips (the so-called interconnects) are responsible for the majority of the energy consumption of these chips – one of the reasons why there is a worldwide search for optical (photonic) interconnects. The problem here is the light source: it has to be small enough to fit in the microscopic structure of the microchips. The output power and efficiency also have to be high enough – and especially the latter was a challenge.

The LED that was developed at the TU Eindhoven has a size of only a few hundred nanometers and has a integrated light channel (wave guide) for transporting the light signal. The increase in the efficiency of this new LED was mostly due to the quality of the coupling of the LED to that light channel.

The research is described in the paper ‘Waveguide-coupled nanopillar metal-cavity light-emitting diodes on silicon’ that appeared in Nature Communications; it can be viewed here.
Source: Elektor

The New Light-responsive Nano LEDs

A team of researchers from the US and South Korea reported a unique type of NanoLEDs with unprecedented brightness levels, that excess 80,000 cd/m2, and also can operate both as light emitters and light detectors.

These new LEDs are about 50nm long and 6nm in diameter. As described in the paper, they included quantum dots of two different types, one of which can enhance radiative re-combinations (useful for LEDs) while the other type leads to efficient separation of photo-generated carriers.

Low- and high magnification scanning transmission electron microscopy images of DHNRs (right) magnified image of the region within the white dotted box on the left.

The research of this invention had been published in a paper titled “Double-heterojunction nanorod light-responsive LEDs for display applications“. The researchers consider the dual-mode LEDs will pave the way to new types of interactive displays.

As we head toward the “Internet of things” in which everything is integrated and connected, we need to develop the multi-functional technology that will make this happen. Oh et al. developed a quantum dot-based device that can harvest and generate light and process information. Their design is based on a double-hetero-junction nano-rod structure that, when appropriately biased, can function as a light-emitting diode or a photodetector. Such a dual-function device should contribute to the development of intelligent displays for networks of autonomous sensors.

The device can reach a maximum brightness in excess of 80,000 cd/m2 with a low turn-on voltage (around 1.7 V). It also exhibits low bias and high efficiencies at display-relevant brightness. The research team reports an external quantum efficiency of 8.0% at 1000 cd/m2 under 2.5 V bias.

Energy band diagram of DHNR-LED along with directions of charge flow for light emission (orange arrows) and detection (blue arrows) and a schematic of a DHNR.

One of the experiments was operating a 10×10 pixel DNHR-LED array under reverse bias as a live photodetectors, combined with a circuit board that supplied a forward bias to any pixel detecting incident light. And by alternating forward and reverse bias at a sub-millisecond time scale, light-detecting pixels could be “read out” as they illuminated the array.

Future applications of the DNHR LEDs include:

  • Translate any detected signal into brightness adjustments;
  • Automatic brightness adjustment in response to external light–intensity change;
  • Direct imaging or scanning at screen level;
  • Display-to-display data communication.
  • Displays can harvest or scavenge energy from ambient light sources without the need for integrating separate solar cells.

Sources: elektor, EETimes

A FPGA controlled RGB LED MATRIX for Incredible Effects

A dot matrix RGB LED graphic panel, managed by a FPGA-based controller board that may be separately used as a demoboard, so to evaluate the potential of the on-board Spartan 6. First installment.

A FPGA controlled RGB LED MATRIX for Incredible Effects – [Link]