In 2011 Prof. Harald Haas (pictured) of the University of Edinburgh demonstrated streaming a hi-def video signal using a light beam as a transmission medium. He went on to explain how this technology might be used to address the growing paucity of free RF bandwidth and suggested that domestic LED lamps may in future provide an internet access point, once the necessary control electronics to modulate the light are integrated into the lamp.
The key to this technique (dubbed LiFi) is a modified type of Orthogonal Frequency Division Multiplexing called SIM OFDM. This splits the serial data stream into thousands of parallel streams, using multiple carrier frequencies to modulate the light source and achieve a high throughput. [via]
LiFi Ready to Go - [Link]
Kerry Wong built a DIY constant current/constant power electronic load. It can sink more than 200W of power:
A while back I built a simple constant current electronic load using an aluminum HDD cooler case as the heatsink. While it was sufficient for a few amps’ load under low voltages, it could not handle load much higher than a few dozen watts at least not for a prolonged period of time. So this time around, I decided to build a much beefier electronic load so it could be used in more demanding situations.
One of the features a lot of commercial electronic loads has in common is the ability to sink constant power. Constant power would come in handy when measuring battery capacities (Wh) or testing power supplies for instance. To accommodate this, I decided to use an Arduino (ATmega328p) microcontroller.
Building a constant current/constant power electronic load - [Link]
Over 60 years of experiences of German company EBM-PAPST in the fans development reflects in an uncompromising quality of products.
It may sound like a phrase, but to rely on a quality is almost always worth – mainly because of overall savings. Long lifetime and energy efficiency will at the end of the day reflect into lower operation expenses. Quality materials sophisticated construction, precise bearings and results from long-term tests say in favor of EBM-Papst fans. EBM-PAPST has in its testing laboratories 1500 operating fans and there can be even found fans continuously operating from 80´s (!). EBM-Papst is quite stringent regarding a declared lifetime and in comparison to other producers it declares „less optimistic” values, as illustrated on an enclosed picture. It means, that if we compare 2 fans from various producers with similar features, it´s very probable that the type from EBM-Papst will have a higher real lifetime. In the EBM-Papst portfolio can be found practically all types of fans and blowers, from smallest to massive industrial ones, axial, radial (centrifugal), diagonal a tangential. The most of fans is also available in a version resistant to dust and water with IP54. EBM-Papst is a pioneer in the development of energetically efficient fans with a significantly lower power consumption and a quieter operation, for example the ACmaxx and GreenTech_EC series.
EBM-Papst portfolio is very wide, that´s why we keep in stock only a few most wanted types and any other type we´re able to provide you upon request. To the standard stock items we newly added also the type 7056ES – AC fan with of a 150mm diameter. 7056ES is a well proven powerful type with a ball bearing and an all-metal construction. Precise ball bearings SINTEC feature a constant low noise during all the lifetime and a low sensitivity to impacts. 27W motor contains an external capacitor and a thermal fuse against overload. High air flow – 330m3/hr, i.e. over 90 litres per second make this type a universal choice for ventilation of various spaces or cooling of electronics and similar.
Fans able to operate continuously for 30 years - [Link]
Jaanus has been working on a buck-boost converter from LT3791-1:
I’m building quite high power (for me) buck-boost converter for a friend. It takes in 12-45 V and has to output regulated 24 V. Total output power has to be more than 300 W. I don’t understand switching regulators well enough to build more than 100 W regulators from 555 timer (that is basically how your computer power supply is built). Just too much phase shifting and output oscillations and whatever else to take into account. You know, the things you learn in electronics classes (which there was none in my school).
Buck-boost converter from LT3791-1 - [Link]
By Shawn Rhen:
Despite the initial investment, solid state lighting (SSL) has proven to be a viable alternative over conventional technologies due to the combined savings in energy consumption and maintenance costs, as well as design flexibility. Furthermore, increased energy savings can be realized with active intelligence such as occupancy and ambient light sensors, as well as external dimming controls to eliminate excessive lighting. Since there are a wide variety of constant current LED drivers requiring a 0-10 volt DC input for dimming control available, the focus of this discussion will be utilizing these drivers with a wireless interface.
Wireless Control of Linearly Dimmed LED Drivers - [Link]
Saelig Company, Inc. (www.saelig.com) has introduced the PSB-2000 Series Flexible Power Supplies – high power density, programmable and multi-range-output DC power supplies offering flexible high voltage-low current/low voltage-high current output characteristics. V/I combinations for a very wide range of applications at up to 800W are covered by six models, including one power booster. The PSB-2000 Series offers an output voltage of 0 to 80V and 0 to 800V, with an output power of 400W or 800W. Series/parallel connections can be applied to PSB-2000 supplies for higher power outputs.
The stylish PSB-2000 Series provides three sets of preset function keys to memorize regularly used settings of voltage, current and power for rapid recall. A serial-controlled Sequence Function, using an RS232C, USB or optional GPIB interface, can produce output power defined by a sequence of set voltage and current steps provided by an attached PC. This capability is valuable for creating standard test procedures for verifying devices under test by quickly changing operating conditions. Read the rest of this entry »
The Arduino compatible board to take your projects beyond your home and garden. Anywhere your imagination takes you.
Prototyping should be rapid. Putting projects together should be as easy as clicking together lego-like building blocks. SODAQ makes it so. SODAQ is a multi-feature microprocessor board that lets you connect sensors and devices to the internet, quickly and with no fuss. It’s designed for connecting things efficiently, running off-grid with built-in, ready-to-go solar power:
Getting data off a device is only half the story – it needs to go somewhere. We designed the SODAQ system to be able to communicate from anywhere, with a GPRS module and all the control code for it included from the start.
It takes the Arduino prototyping concept, makes it simpler, and extends it. No breadboarding or soldering required, but with plenty of memory, sockets, solar panel and battery control, and extra features, all on one board.
The board has built in sockets for Grove modules; a realtime clock; extended flash memory; USB on-board; and the Bee socket can take any WiFi/RF/XBee or other compatible plugin for communications instead of our GPRS module.
SODAQ: a lego-like, plug-in, rapid prototyping board - [Link]
Julian Ilett demonstrates his Arduino Solar Charge Controller. He has mounted all of his Arduino modules to a piece of wood to keep everything nice and neat. [via]
“High efficiency values (96% – 97%) are achievable when the buck converter is stepping down from 18v to 12v. With a 72-cell panel and the converter stepping 35v down to 12v, the efficiency drops to around 88%.”
Arduino Solar Charge Controller - [Link]
Glyn Hudson over at OpenEnergyMonitor has developed this remote temperature and humidity monitoring node, the emonTH:
The emonTH supports both the DHT22 (humidity and temperature) and DS18B20 either onboard or remote temperature sensor. The default software will search for the presence of either sensor at startup. If both sensors are found it will return humidity from the DHT22 and temperature from the DS128B20. If only the DHT22 is found it will return both humidity and temperature readings from this sensor, finally if only the DS18B20 is found only temperature readings will be returned. In the future I would to expand the code to support multiple DS18B20 sensors on the one-wire bus.
emonTH – Wireless temperature and humidity monitoring node - [Link]
A multifunction WiFi Shield that will boost your Arduino systems.
Have you ever wanted to include WiFi functionality into your Arduino system but been scared away by the shear cost and complexity of it. Not to mention that you normally want to have a few other things in there such as maybe an SD card to be able to give those web pages some flare, a real time clock maybe and what about some non volatile SRAM memory to store all that real time sensor data that you have to take good care of.
Arduino compatible WiFi Shield with multiple functions - [Link]