Syst3mX @ instructables writes:
One day I was sitting behind my desk at work and I got that weird need to build something, after looking around for a bit I got my eye on an LED matrix and that sparked an idea in my head : “I WANNA MAKE A TAMAGOTCHI”.
So for those of you that don’t know what the heck is a Tamagotchi here is a little snip-it from wikipedia :
“The Tamagotchi (たまごっち Tamagocchi?) is a handheld digital pet, created in Japan by Akihiro Yokoi of WiZ and Aki Maita of Bandai. It was first sold by Bandai in 1996 in Japan.”
So my take on this classic toy is to make it in to a desktop gadget with an LED matrix for a display, and an Arduino for brains to make it more accessible to people. With that said join me as we design,build and program the World’s first (As far as I know) desktop Tamagotchi.
Make a Desktop Tamagotchi - [Link]
jollifactory @ instructables writes:
Here, we show how a 7 Bi-color 8×8 LED Matrix Scrolling Text Display is built, in which messages and commands can be sent to it via Bluetooth using an Android Smart Phone. Logically, any devices capable of sending text messages via Bluetooth may be adapted to work with the display.
To build this project, basic electronics component soldering skills and some knowledge on using the Arduino or Arduino based micro-controllers are required.
The reason for building a 7 LED Matrices long display is that it is quite adequate for ease of reading scrolling text and also because the largest tinted acrylic sheet easily available in Hobby or Art shops is 18 inches by 12 inches, which is just the right length for making the enclosure for the display as each LED matrix is around 60mm x 60mm in size.
7 Bi-color LED Matrix Scrolling Text Display - [Link]
hardwarehank @ instructables.com writes:
The Atmel ATTiny85 chip is an 8-pin MCU that is totally awesome. If you’ve been programming with the bigger boys (the ATMega series), these are a nice adventure – you’re rather limited in the number of output pins, but a creative design gives us a lot of flexibility in a very small package.
You’ve seen them – those “Apple computers.” Probably in the hands of some Hipster in Portland, while riding his fixie and wearing those thick framed glasses. That pulsating light when Apple laptops are asleep is so … sooooothing. You just want to go to sleep watching it. You know you do.
Today, we’re going to replicate that using our ATTiny85. It’s really easy, and most of it can be implemented in hardware instead of code (!!!).
Apple-style LED pulsing using a $1.30 MCU - [Link]
xlisus @ instructables.com writes:
Choose the hue of light that makes you feel more comfortable.
Simple bluetooth remote control from which you can modify lighting from your mobile device or tablet.
- You have two separate RGB channels where you can get different colors per channel.
- Control adjustable intensity.
- Do it yourself .
- Thanks to the arduino platform in minutes you ‘ll Omniblug armed and ready for use.
Discover all the features provided. Is very easy install this small device.
Android Bluetooth Control Led RGB - [Link]
This article is another step forward in learning more about Arduino. In our previous article, I have written in detail about blinking an LED using Arduino. We have demonstrated 5 simple led based projects using arduino, which will help you to learn its basic concepts.
Simple LED Projects using Arduino - [Link]
This GU10 LED spot light is cheap (£3 including postage) and bright. But it’s also lethal! There’s a 50% chance of putting live mains within a few microns of the metal casing (which is what you’ll be holding when you insert it) and there’s no earth to protect you. It’s like playing Russian Roulette with 240v AC mains. This sort of thing gives new technology a bad name. Avoid it if you want to stay alive.
Dangerous GU10 LED Spot Light is Cheap and Bright but could Kill You – Seriously - [Link]
Julian Ilett writes:
I discovered that due to a lucky co-incidence of voltage and internal resistance, a 100W LED can be connected directly across the terminals of two 18V Nickel Cadmium power tool batteries. And that means you can build a 100 Watt (7,500 Lumens) flashlight for less than $10 (not including batteries).
Monster 7,500 Lumens 100W LED Flashlight for under $10 - [Link]
cpldcpu did a teardown of an external USB battery:
The device has a USB micro-b socket which is used as 5V input for charging, and a normal USB-A socket as 5V output. The output power can be turned off and on by a toggle button. There are LEDs to indicate active power out (blue) and charging (red) states. The pictures above show the innards of the device. Most space is taken up by an ICR18650 LiIon battery, which are relatively common devices with 2600mAH. In addition, there is a tiny tiny PCB. The rear side of the PCB is dominated by a 4.7µH inductor, which is part of the boost converter to convert the 3.7V of the battery to the 5V USB output.
Tear down of a cheap external USB battery - [Link]
jojo @ circuitstoday.com writes:
When we learn a new programming language in computer science (say C, PHP or Java), we begin the learning curve with the classic “Hello World” program. We learn some essential keywords used in the programming language, then we learn the structure of the language and finally we begin to play with the language by making it display the two words “hello world” in our computer screen. So that’s how we begin to learn a programming language used to build computer applications. Our world of embedded systems is a little different. We create software to control hardware. In our world, we begin our learning curve by saying “hello world” using an LED. Our way of “hello world” is blinking an LED using the micro controller under study.
Blink LED with Arduino – say Hello World - [Link]
High color fidelity approaching an ideal is a common feature of „high CRI“ Osram LEDs with CRI up to 96.
When you recall to lessons of physics from your basic- or grammar-school, probably you´ve heard a term „black body radiation”. As we know, each object with a given temperature radiates in a wide range of wave lengths, while a maximum of a radiation depends on its temperature. We mention it because the Sun also operates on this “principle” and its spectrum (light) depends mainly on its surface temperature. Temperature of an object is also the most important factor influencing whether the light will be “warm” or “cold”, that´s why a term color (chromacity) temperature CCT is used.
Even though a portion of radiation (some wave lengths) is absorbed in atmosphere, it can be said that it is very near to a black body spectrum and it´s ideal for us in respect to a pleasant and true color perception.
There are several methods to evaluate color fidelity and one of the most important is so called CRI (color rendition index, maximum = 100). To an ideal light source with CRI =100 is very near a classic incandescent bulb, even though it´s spectrum is shifted towards warmer tones. Unfortunately a light spectrum gained from hot surfzce object also contains a large portion of thermal (infrared) radiation, what causes a low efficiency of incandescent bulbs. However LEDs deploy emission of photons on an other principle (change of electrons energy), so their surface is in fact “cold” in comparison to what temperature a black body radiator should have to gain a similar spectrum.
Modern LEDs have a high CRI, usually over 70. But among LEDs we can find types with even higher CRI (above 80) , as well as “color champions” with even higher CRI. To such champions also belong LEDs from the OSLON Square series, which we introduced to you in our article New LED OSRAM OSLON Square withstands up to 1.5A. Since then company Osram advanced in development and was able to make types with a typical CRI 96 (!), for example LCWCQAR.CC-MPMR-5J7K-1 (4500K).
Light fidelity of this LED is extremely high and such light is very suitable for lighting of areas with high requirements for a light quality, like for example: galleries, museums, shops, photographic ateliers as well as for an everyday work. Despite a high CRI, this particular type also features a considerable efficiency of 180-224 lm/700 mA and a max. current up to 1500 mA.
Among novelties from company Osram can also be found the Oslon Square 2nd generation with even betterthermal features increasing lifetime and efficiency at high temperatures. Moreover this new 2-nd version is sorted (binning) at 85°C, what ensures minimum color in a real operation.
Almost perfect light from the Oslon Square LED - [Link]