Multi-brightness LED controller draws zero off-current

T A Babu @ edn.com has a design idea of a led controller with some nice features:

The key features of this Design Idea are:

Soft switch on/off operation

Zero current drain in sleep mode

Two level dimming

Low battery protection

Simple controller based on CMOS 4017 Johnson counter

Multi-brightness LED controller draws zero off-current – [Link]

Accelerometers for vibration measurements & wireless condition monitoring

Graham Prophet @ eedesignnewseurope.com discuss about two new MEMS accelerometers from Analog Devices:

Analog Devices (ADI) has added two devices to its low noise, low drift, low power, three-axis MEMS accelerometers. The low noise performance over high frequencies provided by the ADXL356 and ADXL357 MEMS accelerometers delivers high resolution vibration measurements that enable the early detection of machine failure in condition monitoring applications.

Accelerometers for vibration measurements & wireless condition monitoring – [Link]

Open Source UV Index Detector

Boris Landoni @ open-electronics.org documents his UV index detector.

It measures solar radiation and visualizes the corresponding value on the integrated display of a miniaturized Arduino, in order to tell us when to expose ourselves to the sun…

Open Source UV Index Detector – [Link]

SEPIC/Ćuk converter sprouts second output

by Gheorghe Plasoianu @ edn.com

Many applications require positive and negative supply voltages, with only one voltage requiring tight regulation. This Design Idea describes a dual-output, hybrid SEPICĆuk converter whose positive output voltage can be lesser or greater than the input voltage. The unregulated negative output is a mirrored replica of the positive output.

SEPIC/Ćuk converter sprouts second output – [Link]

Reverse engineering the 76477 sound effect chip

Ken Shirriff has written an article on reverse engineering the 76477 “Space Invaders” sound effect chip:

Remember the old video game Space Invaders? Some of its sound effects were provided by a chip called the 76477 Complex Sound Generation chip. While the sound effects1 produced by this 1978 chip seem primitive today, it was used in many video games, pinball games. But what’s inside this chip and how does it work internally? By reverse-engineering the chip from die photos, we can find out. (Photos courtesy of Sean Riddle.) In this article, I explain how the analog circuits of this chip works and show how the hundreds of transistors on the silicon die form the circuits of this complex chip.

Reverse engineering the 76477 sound effect chip – [Link]

Free PADS PCB packages from Mentor/Digi-Key

by Graham Prophet @ eedesignnewseurope.com:

Two versions of the PADS software package (by Mentor, now a Siemens business) have been made available through distributor Digi-Key. Positioned as design software for “the aspiring innovator” both the free and the $499 versions include access to parts libraries and to a circuit simulator.

Free PADS PCB packages from Mentor/Digi-Key – [Link]

Embedded vision development kit targets mobile & ‘edge’ applications

by Graham Prophet @ eedesignnewseurope.com:

Lattice Semiconductor positions its Embedded Vision Development Kit as the first of its type, that is optimized for mobile-influenced system designs that require flexible, low cost, and low power image processing architectures, by which the company refers to Robotics, Drones, ADAS, smart surveillance and AR/VR systems

Embedded vision development kit targets mobile & ‘edge’ applications – [Link]

Printed Two-Dimensional Transistors

Researchers from AMBER (Advanced Materials and BioEngineering Research) and Trinity College (Dublin), together with the TU Delft have succeeded in producing printed transistors, which are made solely from two-dimensional nano materials. These materials have characteristics with much promise and, importantly, can also be produced very cheaply. Possible applications for this procedure are food packaging with a digital countdown timer for the use-by date, wine labels which will show when the contents is at the optimal drinking temperature, security for bank notes and perhaps even flexible solar cells.

The researchers, under the leadership of professors Jonathan Coleman and Georg Duesberg, have used standard printing techniques to combine nano sheets of graphene, which are used as electrodes, with two other nano materials (tungsten diselenide and boron nitride) that function as channel and separator. The result is functional transistor made from nano sheets using only printing technology.


Two-dimensional transistors, as such, are not new – they have already been manufactured using a chemical deposition from the vapor phase. A significant disadvantage of this and other existing methods is their high cost. In comparison, printed electronics is based around printable molecules formed from carbon compounds, which can easily and cheaply be turned into a usable ink.

The material of the printed electronics comprises a large number of nano sheets of different sizes (which are sometimes also called ‘flakes’). During the printing process these are layered in a random pattern. The consequence of this is that the printed material is somewhat unstable and the performance has some limitations.

The transistors printed this way are a first important step towards printed 2D-structures made from a single nano sheet. This would dramatically improve the performance of printed electronics. This is the subject of current research at the TU Delft.

Jonathan Coleman from Trinity College is a partner of Graphene flagship, an EU initiative that in the next 10 years has to stimulate new technologies and innovation.

Source: Elektor

Zephyr Project Hosted by Linux Foundation — Yet Another RTOS for IoT

What is Zephyr?

Zephyr is a small footprint IoT RTOS (less than 10kB) with no user-space and dynamic allocation which make it suitable to run on resource-constrained platforms. Moreover, it’s modular and supports multiple architectures, including ARM, X86,ARC, NIOS-II and others).

Zephyr is an open source project under Apache 2.0 License and hosted by Linux Foundation. However, Being hosted by Linux Foundation doesn’t mean that Zephyr project is a scaled version of linux OS.

As connectivity is one of the main concerns in IoT, Zephyr provides support for IEEE 802.15.4, Bluetooth V4.0, NFC, WiFi and 3GPP. While security is another concern it also provides a cryptographic library based on TinyCrypt2 and mbedTLS.

Why is Zephyr?

Zephyr claims that its kernel offers a number of features that distinguish it from other small-footprint Oses. Zephyr works on single address-space, where both the application and kernel are combined on a single image and execute in a single address-space; they like to call this feature as library-based RTOS (“kernel-less”) so there is no need for dynamic loading at run-time . Moreover, Zephyr has two Kernel modes : “Nanokernel” — with limited functionality targeting small footprint (below 10k) and “Microkernel” — a superset of nanokernel.

Where is Zepher?

Zepher supports variety of architectures and development boards including X86 boards like MinnowBoard, Genuino 101, Quark D2000 and others; and ARM boards like Arduino Due, ST Nucleo F401RE and others.

The Development Environment supports Windows, Linux and MAC OS. To get started with Zephyr, refer to the official getting started page.
This young and fresh RTOS is already adapted by commercial products like Grush — an interactive Bluetooth toothbrush.

 

What Is Household Ground?

Image source: RimstarOrg Youtube channel
Image source: RimstarOrg Youtube channel

RimstarOrg published an interesting video on his Youtube channel to demonstrate why In north America you can find 3 holes in the electricity socket; which are hot, neutral and ground.

Image source: RimstarOrg Youtube channel
Image source: RimstarOrg Youtube channel

The hot wire goes to a breaker-panel and then to electricity grid and finally to a transformer somewhere. While the neutral line is connected with a bar in the breaker-panel and goes directly to the electricity grid and then to the transformer. Mostly, these wires’ colors are respectively black, white.

Breaker-panel — Image source: RimstarOrg Youtube channel
Breaker-panel — Image source: RimstarOrg Youtube channel

To understand why having a ground in household appliances is important, the video explained a use-case; a microwave-oven with 3 wires electricity plug where the electricity flows between the hot and the neutral, while the ground is connected to the external case. However, if the hot wire isolation gets damaged and attached to the case, the grounded case will make a low resistance path for the electricity. This will protect you from an electric shock because the electricity in this low resistance path will be very high forcing the breaker switches off.

Image source: RimstarOrg Youtube channel
Image source: RimstarOrg Youtube channel

Having a ground in the electrical system can play a role in the places where lightning can occur by forming a discharging path for charged cases in your house.
To understand more about household ground and other different meanings and applications of earth and ground watch the complete video below:

 

Source: Adafruit Blog