Ray reports he’s just finished working on a new open source wearable electronics controller board called SquareWear. It’s small (1.6″x1.6″) and has built-in USB port (used for programming the microcontroller, USB serial communication, and charging battery). It also has 4 on-board MOSFETs for switching high-current load (up to 500mA). The board is based on Microchip’s PIC18F14k50, and includes a SquareWear library to make it as easy to use as Arduino. Check out RaysHobby website for the source code and programming guide.
SquareWear open source controller board - [Link]
Unit is based on Arduino Atmega328P MCU, with over 430 UV LEDs. The PCB board is made using Toner transfer method and isn’t perfect. It was just too big and I was too lazy to do it again. However, marker here, scratch it there and it it good enough.
The unit itself is on single sided copper clad board, no additional cables, no narrow paths (except for one for power on the MCU). Design is straight forward. It’s designed to be powered from 12V source (computer) and take around 2,7Amps @ full power which means around 30Watts.
DIY UV Exposure Unit with LED and Arduino - [Link]
An Arduino-based clock with 180 RGB LEDs. The LEDs are driven via 12 TLC5925 1- channel constant-current addressable drivers – [via]
Its built on doublesided copper clad board using Toner transfer method. The routes aren’t smaller than 0.44mm and all vias are made for 0.8mm drilling (truly DIY). Just around 5 vias are under a component and 7 segment displays have singnals only from bottom side (for easy soldering)
- 180 RGB LEDs driven by TLC5925 constant current LED drivers
- each LED addressed separately (12x TLC5925 with 16 outputs each)
- each colour adressed individually
- 4x 7 segment LED display
- Atmega328P as MCU
- DS1307 real time clock
- Photoresistor (for adjusting brightness)
- And DHT11 for temperature and humidity
- Backup battery for clock
- 5V DC (eg USB)
Clock with 180 RGB LEDs on home-etched circuit board - [Link]
Interesting and info-packed video from Osram on how they make LEDs – [via]
How LEDs are Made - [Link]
1962: Nick Holonyak, Jr. demonstrates the world’s first visible light-emitting diode (LED) to General Electric suits, changing the world of lighting forever. Holonyak later said that the LED would replace incandescent lights. It’s just taking a little bit longer than expected.
Scientists at the GE Advanced Semiconductor Laboratory were researching a way to create energy-efficient visible light from LEDs. The incandescent lights that we still use today rely on igniting a filament housed in a vacuum to create light. The process is inefficient and only uses 10 percent of available energy to produce light. The rest is lost as heat.
In the early 1960s, the only light emitted from LEDs was infrared. The race to produce a visible LED had GE researchers scrambling to be first.
50th Anniversary of the Visible Light LED - [Link]
PureVLC brings its first Visible Light Communication (VLC) product to the market. VLC transmits data wirelessly using visible light as its medium instead of radio waves. VLC was demonstrated over a year ago when Harold Haas, professor of Mobile Communications at the University of Edinburgh, successfully demonstrated the technology at a TED conference. He streamed a HD video to a screen using a LED light bulb as transmitter.
Using the visible light spectrum to transfer data wirelessly will ease the burden on the overcrowded radio frequencies. The visible light spectrum is 10,000 larger than that of radio. VLC can potentially realize ultra-high-speed transfer rates and high data density. [via]
LEDs Just Got Brighter, They Now Talk Too - [Link]
LT series LED drivers with 10-100W power represent a complete solution with wide possibilities of control. Exceptionally narrow and slim design, remained even at high-power versions, provides a high flexibility of use.
Power supplies for LED lighting (so called drivers) are available from many producers, in a various qualitative level. Why to decide just for the LT series from German company Friwo? Here are few reasons:
- precise design, safe operation and a long lifetime
- voltage and current regulation in one device
- high efficiency and a possibility of dimming in a range of 0-100% directly via a CTRL pin
- modules are available in 10-100W power, with a possibility of customization by laser directly at production also available a module for dimming – so called DIMMbox, further expanding possibilities of control (switch, 1-10V, DALI) and with a possibility of synchronization with up to 1000 slave units
- very small cross section of modules (21x30mm, resp. 24x30mm at LT100) – applicable even in very tiny conditions
Wide control possibilities of LT series modules are perhaps the most interesting. Modules contain a galvanically isolated CTRL input, by which it is possible to switch on/ off the module without disconnecting from 230V mains. CTRL pin also serves for regulation of an output current. For this purpose, only one resistor (or a potentiometer) is necessary – connected between SEC+ and CTRL pins, with a value counted by a simple formula in the datasheet. The output current can also be controlled by an external voltage in the range of 0-1,8V connected to SEC- and CTRL, as well as by means of a PWM TTL (0/5V).
Further possibilities of control are provided by a standalone additional module DIMMbox. DIMMbox operates as an (almost) lossless PWM regulator with a MOSFET switched at f=600Hz. DIMM-BOX connected to any series LT driver enables to regulate an output current in a range of 10-100% or 0% (OFF) via a usual switch (switch-dimm“ mode), via a linear voltage 1-10V and also a DALI interface. DIMMbox tests after switching on, which of three methods of control is used and consequently accepts only signals from a given input – until switching off the module. DIMMboxes can be connected through SYNC inputs, ensuring the same level of dimming for all modules. Enclosed pictures will provide you the best idea about possibilities of connection.
Friwo drivers not only drive your LEDs but even control them - [Link]
The new XLamp XP-E2 LEDs from Cree are claimed to deliver more lumens per watt and lumens per dollar to lower system costs for existing XP-E and XP-G designs. The new LEDs can increase the light output of existing XP-E designs at the same cost and power or reduce the system cost with fewer LEDs, enabling lighting manufacturers to deliver better lighting systems with minimal redesign.
The LEDs have the standard XP footprint (3.45 x 3.45 mm) and are optically compatible with all XP LED versions, including the popular XP-E and XP-G. The LEDs generate cool white light (6000 K) at up to 128 lm/W at 350 mA and 85 °C or 143 lm/W at 350 mA and 25 °C and are suitable for a broad spectrum of high-lumen applications for indoor and outdoor lighting, portable lighting and lamp retrofits and. [via]
New LEDs Double Lumens per Dollar - [Link]
The concept for this small birthday present was to create a small heart shape with red LEDs and then to draw a heart shape underneath it on the PCB as a backdrop. Then a small processor was added to control the heart shape of LEDs for both fade and pattern control. The method of control that we use (PWM) allows us to save precious battery life, control the exact brightness of each specific LED and create this tiny but awesome project.
LED Heart PWM Fading – [Link]
We create a lamp controlled by SMS using a GSM shield, a RGB shield and a Arduino UNO. Due to the simplicity of these boards, simply plug one over the other and connect a strip led to have a lighting effect. Then sending normal text messages from any phone, you can turn on and choose the color to set.
IKEA SMS lamp with GSM shield - [Link]