The Akafugu LED Candle is an artificial candle that imitates the flickering of a real candle. Use it in place of a real tea candle: It will fit inside a tea candle casing or any holder made for tea candles.
- Randomly flickering LED: Imitates a candle
- Fits inside a tea candle casing
- Open Source Firmware (available at GitHub)
- Open Source Hardware: Eagle PCB design files available at GitHub
- On-board ISP header for upgrading firmware
LED Candle - [Link]
Raj from Embedded Lab shows in his latest tutorial guide how to implement adaptive brightness control to seven segment LED displays for optimum readability in all illumination conditions. The technique has been demonstrated by constructing a temperature and humidity meter that adapts the brightness of the seven segment LED displays to the surrounding lighting conditions.The project uses a general purpose LDR to sense the surrounding illumination and MAX7219 to drive the LED display.
How to implement auto-brightness adjustment to seven segment LED displays – [Link]
This reference design is for a high-voltage boost current source for very long strings of LEDs. Applications that use long LED strings include, but are not limited to, streetlights and parking garage lights. Long LED strings can be a very cost-effective way to drive LEDs. Also, since the LEDs will have exactly the same current, brightness variations are nicely controlled. This design has a 24V input, up to a 75V LED output, and drives 1.5A through the LED string (or strings, if paralleled). The measured input power is 115.49W and the output power is 111.6W for an efficiency of about 96.6%.
112W Boost driver for long strings of LEDs - [Link]
Jack Shandle writes:
LED-based lighting has many advantages including a small footprint, exceptionally long lifetimes and excellent lighting efficacy in lumens per watt. As LEDs have become popular, the challenges of designing with them have become more evident – with thermal management topping the list.
The challenge begins with the source itself. High-powered LEDs do not generate infrared radiation, which is the primary way competing light sources dissipate energy that is not visible light. Instead, 75 to 85 percent of energy used to drive an LED is converted to heat, compared to 42 percent for a typical linear fluorescent, 37 percent for a metal halide bulb, and only 19 percent for an incandescent light source. In LED-based system designs, this heat must be conducted from the LED die to heat sinks, the circuit board, housings or luminaires. In addition, power dissipation in other parts of the system, such as the power supply, must be minimized.
ABCs of LED Thermal Management - [Link]
Long time ago I came across this page http://tobe.nimio.info/project/moodlamp, where Toon Beerten created a Moodlamp using a PIC16F628 µC. I remember that back then I didn’t have much knowledge on µC’s programming, so the first thing I did was to buy a Arduino board, and since that time I have been learning a lot and making many different projects with it…
Open Hardware MoodLamp - [Link]
The Temperature Candle is a relatively simple design which essentially boils down to a 8-pin microcontroller, a temperature sensor and voltage reference and a RGB LED on a 1.5″ diameter PCB – the same size as a standard votive candle. The micro flickers the LED like a candle at a color determined by the ambient temperature. The color gives an indication of the room temperature in reference to the recommended sleep time temperature for
babies to reduce the risk of SIDS (Sudden Infant Death Syndrome).
The candle can also blink the temperature by pressing a reset button on the PCB.
This should be a relatively cheap kit and it uses all thru-hole components so it should be easy to assemble. Using a simple micro, it can also be a good introduction to microcontrollers, and is designed with a jack to connect to Microchip’s Pickit 3 programmer / debugger.
You can see more information and look at all the design files on its project page.
The Temperature Candle - [Link]
To drive a 3×3 mm sized LED with a current of 1.5A was unthinkable till lately. OSLON Square enables it, thus providing a free hand in designing powerful and compact LED applications.
New OSLON Square series is suitable for outdoor and indoor LED applications, as well as for exceptionally compact designs. At the first look, OSLON Square is similar to the OSLON SSL series. The difference is in the substantially larger chip, what enabled to double a maximum driving current.
Advantages / Features:
- driving current up to 1.5A
- 3×3 mm ultra compact dimensions
- lifetime of more than 50000 hours
- excellent corrosion resistance
- suitable even to humid environment
- excellent color consistency thanks to a fine binning
- thermal resistance RTHJS only 3,8K/W
But the power and ultra compact dimensions are not the only advantages of OSLON Square. Among another features also belongs robustness – the SMT package doesn´t contain silver, that´s why it´s highly resistant even to the most humid environment. White reflective layer contributes to better usage of the reflected light and helps to efficient usage of every lumen during the whole lifetime. Thanks to a very low thermal resistance of the package, lifetime of over 50 000 hours can be easily obtained, even at high driving currents. Resulting low operational temperature helps to reach high light output and a long lifetime. Fine binning system and usage of the latest phosphor conversion technology ensure perfect color consistency and stability.
Four basic groups are available:
- EC, white with a balance of luminous flux and CRI min. 80.
- PC, neutral white with a maximized luminous flux, while keeping a very good CRI min. 70. Typical brightness is 245 lm/ 5000K/ 700mA.
- Streetwhite, cold white with a maximized luminous flux with CRI min. 65.
- EQW, intended for technical and industrial lighting with a maximum energy saving (color coordinates Cx=0.37, Cy=0.44).
Further information will provide you the OSLON Square flyer and application details. It is worth to mention, that OSLON Square neither other power LEDS without a heatsink should never be tested without a proper soldering to a cooling baseplate/PCB – because of a very small thermal capacity a tested LED would be destroyed within few seconds.
New LED OSRAM OSLON Square withstands up to 1.5A - [Link]