ZXLee built a simple sensor for Arduino which allows him to detect colors. The idea lies behind using red, green, blue LEDs and Light Dependent Resistor (LDR). Lee Zhi Xian writes:
Previously I have made a colour sensor using Arduino but don’t have the time to update it on my blog. Today I am going to share the details of this mini project. Basically, the sensor consists of three LEDs and Light Dependent Resistor (LDR). The LDR will detect the colour and display it to another RGB LED. Besides display it on the RGB LED, the colour will also display on PC. RGB LED is commonly used in display colours on LCD or OLED such as the monitor and television.
Simple technique of sensing colors using Arduino - [Link]
The MicroView is the first chip-sized Arduino compatible that lets you see what your Arduino is thinking using a built-in OLED display.
You’ve never seen an Arduino™ compatible like this. With a built-in OLED (Organic Light Emitting Diode Display) you can see what your Arduino is thinking without having to connect it to your computer.
No more cryptic “Hello World” LED blink sequences or shoehorning oversized displays onto your tiny Arduino™. Development is much easier when you can see what’s going on.
MicroView: Chip-sized Arduino with built-in OLED Display! - [Link]
Zak Kemble build a digital wristwatch with a 1.3″ 128×64 OLED display & AVR ATmega328P microcontroller:
The main incentive behind this project was to see how much I could cram, in terms of both hardware and software, into a wristwatch-like device that is no larger than the display itself. An OLED display was chosen for being only 1.5mm thick and not requiring a backlight (each pixel produces its own light), but mostly because they look cool. The watch was originally going to have a 0.96″ display, but this proved too difficult to get all the things I wanted underneath it. Going up a size to 1.3″ was perfect.
DIY OLED digital wristwatch - [Link]
Steven Keeping writes:
LEDs are a rapidly maturing technology that is making big inroads into the conventional lighting market. However, it is not the only new lighting technology in town. Organic LEDs (OLEDs) are now being considered as an option for some architectural lighting applications after gaining popularity as a display technology offering vibrant color without backlighting. OLEDs differ from conventional LEDs in that the electroluminescence is not derived from a semiconductor junction, but is generated from a film of organic compound. That makes OLEDs simple to manufacture into large, lightweight, and even flexible panels. However, despite some key advantages over traditional LEDs, the devices are not yet available as a commercial lighting option primarily due to low efficiency and high costs compared to solid-state light sources. This article describes the performance of today’s commercial-lighting OLEDs and compares it to established technologies, including LEDs.
OLEDs Move Closer to Mainstream Lighting - [Link]
With OLEDs approaching production maturity, Osram has announced that it is researching another technology that could change the world of lighting: light emitting foils produced in a printing process. The foils are based on light-emitting electrochemical cells made from organic materials, known as organic light-emitting electrochemical cells (OLECs). Although similar to OLEDs, they have a conductive and light-emitting layer containing a liquid material instead of a solid material. This active layer contains freely mobile ions in the liquid phase. When a voltage is applied to the active layer, the ions migrate to the edge. This allows charge carriers to be injected into the layer, where they recombine to emit light in the same way as a light-emitting diode. With suitable combinations of materials, any desired color of light can be obtained. [via]
Printed Light-Emitting Foils Could Challenge OLEDs - [Link]
Since we’ve been busy adding quite a few I2C sensors and breakouts lately, I thought this technical overview of the 2-wire “Inter-Integrated Circuit” bus might be handy. I2C isn’t fast (typically limited to 400kHz in most real-world situations), but it’s convenient since it only requires two pins and more than 120 devices can be connected on the same bus, address space permitting. For low-pin count devices, it can be a real life-saver since you can hook an OLED display, a DAC, a 7-segment display and 16 servo motors up to your Arduino with a measley two pins and some careful coding! The full bus specification is available from NXP in UM10204 – the bus was created by Philips, whose semiconductor branch later became NXP — but the more concise information from Embedded Systems Academy might be easier to digest as a starting point. The FAQ has some very good information in it.
I2C Bus Technical Overview - [Link]
Physicists at the University of Utah (USA) have invented a new ‘spintronic’ organic light-emitting diode (OLED) with the potential to be brighter, cheaper and more environmentally friendly than existing LEDs. They made a prototype of what is called a spin-polarized organic LED, or spin OLED, that emits orange light. In time the new technology could be extended to emit red and blue light, and possibly even white light. It may take a while for the new LEDs to go commercial, because they only operate at cold temperatures (-33 °C), so more work is needed to develop practical devices.
The new OLED is based on spintronic devices, which utilise the spins of electrons in a semiconductor material to store or gate data. The researchers discovered that with key advances in the organic semiconductor material, spin valve devices could also be made to emit light. The first advance is to use deuterium (‘heavy hydrogen’) instead of normal hydrogen in the organic layer, which increases efficiency. The second advance is to deposit an extremely thin layer of lithium fluoride on the cobalt electrode, which allows electrons to be injected on one side of the spin valve while holes are injected on the other side. This makes the spin valve bipolar, unlike older spin valves which only allow hole injection. [via]
New OLED Spins Brighter - [Link]
Arduino Temperature Humidity Sensor @ PlastiBots – [via]
The projects I do tend to fall in one of two buckets – either proof-of-concept (so I can learn new stuff) or items that have some sort of functional use. The need for this project came about when my wife was prodding me about the humidity in the house and whether our humidifier was doing it’s job correctly. Most people would just go out and buy a temp / humidity sensor and be done with it. However, if you have a look around here, you will see that I don’t fit that mold. Instead, I decided to build an accurate temp / humidity sensor with a Sensiron SHT11 to read the values, a RBBB Arduino kit to process everything and an Adafruit 128×32 OLED to display the results – all wrapped up in… LEGO! Read on for more…
Arduino Temperature Humidity Sensor - [Link]
These displays are small, only about 1″ diagonal, but very readable due to the high contrast of an OLED display. This display is made of 128×32 individual white OLED pixels, each one is turned on or off by the controller chip. Because the display makes its own light, no backlight is required. This reduces the power required to run the OLED and is why the display has such high contrast; we really like this miniature display for its crispness!
Monochrome 128×32 OLED graphic display - [Link]