Tutorials

 

Pogo Pins and Photographing LCDs

This post is a new product post, a tutorial and a behind the scenes look, all about Pogo Pins.

Pogo pins are small spring loaded pins that are used to make temporary connections to circuit boards. They are typically use for automated circuit testing or for programming Microcontrollers.

 

 

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8 Breadboard Hacks

A few hacks to make bread boarding easier…

1. Hacking the power buses

The power buses on a breadboard are constructed in multiple pieces. To get continuity down the length of the bus continue reading…

ATmega168A Pulse Width Modulation – PWM

Dimming an incandescent bulb is easy. Simply adjust the current down using a potentiometer and you are done. Dimming an LED is another story entirely. When you reduce current through an LED there are unintended consequences like color shifts and dropouts. A better way is to use Pulse Width Modulation (PWM).

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Extending Terminal Blocks

This week we have something that is so simple, it hardly qualifies as a tutorial, so let’s call it a “tip” and get started.

For some time we’ve stocked 2 pin and 3 pin terminal blocks. These terminal blocks have standard 5.08mm spacing, so they fit in all our development and prototyping boards. This is all good, but what do you do if you need a 4-way, 5-way or even bigger terminal block?

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Soldering is Easy

Jeff Keyzer, Mitch Altman and Andie Nordgren have created a seven page comic book about soldering. The style reminds me a little of Forrest Mims’ Getting Started in Electronics.

In any event it is a great book and will be part of a bigger book “How to Make Cool Things with Microcontrollers (For People Who Know Nothing)” which will be released later this year.

The Authors have been kind enough to release the comic under a Creative Commons license (Attribution-ShareAlike), so you are free to teach with it, color it, modify it, share it with your friends, translate it, and basically do whatever you like with it!

The complete comic book is available for download here:

“Soldering is Easy” Comic Book (PDF)

Analogue to Digital Conversion on an ATmega168

Many AVR microcontrollers are capable of doing Analogue to Digital Conversion. The ATmega168 has 6 ports (8 ports on the SMD packages) that can be used for analogue input. This tutorial shows you how.

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Reading and writing Atmega168 EEPROM

EEPROM (Electrically Erasable Programmable Read Only Memory) Is non-volatile memory, meaning it persists after power is removed. The ATmega168 microcontroller has 512 bytes of EEPROM which can be used to store system parameters and small amounts of data. This tutorial shows you how to read and write EEPROM.
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AVR Eclipse Environment on Windows

In this tutorial we will show you how to setup an AVR Eclipse development environment on Windows.
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AVR Memory Architecture

The AVR family of microcontrollers use a modified Harvard Architecture which uses 3 types of memory, most of which are on chip.
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Electronics

 

Electronics

New family of materials for energy-efficient information storage and processing

 

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A schematic illustration of the crystal structure of h-RFeO3. The arrows on the Fe sites indicate the atomic magnetic moments. The coexisting spontaneous electric polarization (P) and magnetic polarization (M) are both along the same crystal direction.

Switching the polarity of a magnet using an electric field (magnetoelectric memory [MEM] effect), can be a working principle of the next-generation technology for information processing and storage. Multiferroic materials are promising candidates for the MEM effect, due to the coexistence of electric and magnetic orders. On the other hand, the coexistence of spontaneous electric and magnetic polarizations is rare in known materials, which hinders the application potential of the MEM effect.

This article briefly reviews a new family of multiferroic materials -- hexagonal rare earth ferrites -- that have been demonstrated ferroelectric and ferromagnetic simultaneously by experiments. Both the ferroeletricity and ferromagnetism in hexagonal ferrites originate indirectly from structural distortions, resulting in so-called improper ferroelectric and ferromagnetic orders. Naturally, structural distortions may mediate the coupling between the electric and magnetic polarizations in hexagonal rare earth ferrites, causing the MEM effect, as predicted by theory.

The possible MEM effect in rare earth hexagonal ferrites is particularly useful for information storage and processing because the non-volatile nature of the magnetic polarization avoids the energy cost of constant memory refreshing and a constant flow of current. The polarity of magnets are used to store information, for example, in the hard disk of computers. The information is modified by "writing" the polarity using a magnetic field, which requires a flow of current that costs significant amount of energy. If the polarity can be switched using an electric field (the MEM effect), the energy-efficiency will be greatly improved, because the generation of the electric field intrinsically needs less power than for generating a magnetic field. The fact that the electric field can be easily localized also suggests application in miniaturized devices.

This research was supported in part by Nebraska EPSCoR.

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Story Source:

The above story is based on materials provided by World Scientific. Note: Materials may be edited for content and length.

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Journal Reference:

1. Xiaoshan Xu, Wenbin Wang. Multiferroic hexagonal ferrites (h-RFeO3,R=Y,Dy-Lu): a brief experimental review. Modern Physics Letters B, 2014; 28 (21): 1430008 DOI: 10.1142/S0217984914300087

Experts call for massive global response to tackle Ebola

 

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The current Ebola outbreak now requires a 'rapid response at a massive global scale,' according to experts. Writing an editorial in Science, Professor Peter Piot, co-discoverer of the virus, says that the epidemic in West Africa is the result of a "perfect storm" involving dysfunctional health services, low trust in governments and Western medicine, denials about the virus's existence, and unhygienic burial practices.

The outbreak which began in December 2013 now spans five countries in West Africa and has so far killed nearly 2000 people, with the WHO predicting that 20,000 may become infected.

Professor Piot, Director of the London School of Hygiene & Tropical Medicine, writes: "This fast pace of Ebola's spread is a grim reminder that epidemics are a global threat and that the only way to get this virus under control is through a rapid response at a massive global scale -- much stronger than the current efforts."

According to Professor Piot, international assistance to the growing local efforts must include support for disease-control activities such as the provision of protective equipment, patient care, and addressing the health, nutritional, and other needs of populations in quarantine.

It is also an opportune time to accelerate evaluation of experimental therapies and vaccines. With the WHO announcing that compassionate use of experimental therapies is ethically justified, even if they have not been tested in humans, Professor Piot comments that "an exceptional crisis requires an exceptional response."

In a separate article in Eurosurveillance, Professor Piot and colleague Dr Adam Kucharski delve deeper into the challenges currently facing West Africa. They warn that the exponential growth in numbers makes tracing and surveillance for Ebola increasingly difficult, and that cases could double every fortnight if the situation remains the same.

Professor Piot and Dr Kucharski write: "Fear and mistrust of health authorities has contributed to this problem, but increasingly it is also because isolation centres have reached capacity. As well as creating potential for further transmission, large numbers of untreated -- and therefore unreported -- cases make it difficult to measure the true spread of infection, and hence to plan and allocate resources."

They also warn that it is not just Ebola patients who are affected by the outbreak. In cities like Monrovia in Liberia, the infection has led to the closure of most health facilities, and as a result, untreated injuries and illnesses have caused further loss of life.

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Story Source:

The above story is based on materials provided by London School of Hygiene & Tropical Medicine. Note: Materials may be edited for content and length.

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Journal References:

1. P. Piot. Ebola's perfect storm. Science, 2014; 345 (6202): 1221 DOI: 10.1126/science.1260695
2. A J Kucharski, P Piot. Containing Ebola virus infection in West Africa. Eurosurveillance, Volume 19, Issue 36, 11 September 2014 [link]

How evolutionary principles could help save our world

 

That's the recommendation of a diverse group of researchers, in a paper published today in the online version of the journal Science. A majority of the nine authors on the paper have received funding from the National Science Foundation (NSF).

"Evolution isn't just about the past anymore, it's about the present and the future," said Scott Carroll, an evolutionary ecologist at University of California-Davis and one of the paper's authors. Addressing societal challenges--food security, emerging diseases, biodiversity loss--in a sustainable way is "going to require evolutionary thinking."

The paper reviews current uses of evolutionary biology and recommends specific ways the field can contribute to the international sustainable development goals (SDGs), now in development by the United Nations.

Evolutionary biology has "tremendous potential" to solve many of the issues highlighted in the SDGs, said Peter Søgaard Jørgensen, another Science author from the University of Copenhagen's Center for Macroecology, Evolution and Climate. The field accounts for how pests may adapt rapidly to our interventions and how vulnerable species struggle to adapt to global change. The authors even chose this release date to coincide with the upcoming meeting of the UN General Assembly, which starts September 24.

Their recommendations include gene therapies to treat disease, choosing drought-and-flood-resistant crop varieties and altering conservation strategies to protect land with high levels of genetic diversity.

"Many human-engineered solutions to societal problems have turned out to have a relatively short useful life because evolution finds ways around them," said George Gilchrist, program officer in NSF's Division of Environmental Biology, which funded many of the Science authors. "Carroll and colleagues propose turning the tables and using evolutionary processes to develop more robust and dynamic solutions."

Applied evolutionary biology just recently made the leap from an academic discipline to a more-practical one, spurred by an effort within the community to better synthesize and share research insights. And--above all--increasing environmental pressures.

"The fact that we're changing the world means that evolutionary processes are going to be affected," said Thomas Smith, of the Department of Ecology and Evolutionary Biology at the University of California, Los Angeles (UCLA) and another Science author. The question is, according to Smith: Do we want to be engaged in this change, or not?

The paper also serves as a platform for establishing a cross-disciplinary field of applied evolutionary biology, Carroll said, and a way to promote the field as a path to sustainable development solutions.

"Evolutionary biology touches on many elements of the life sciences, from medicine to conservation biology to agriculture," said Smith. "And unfortunately, there hasn't been an effort to unify across these fields."

This disconnect exists despite the use of evolutionary tactics in many disciplines: treating HIV with a cocktail of drugs, for example, to slow pathogen resistance. And the effects of evolution already swirl in the public consciousness--and spark debate. Think of the arguments for and against genetically modified crops, or warnings about the increasing price of combating drug resistance (which costs more than $20 billion in the U.S. each year, according to the nonprofit Alliance for Prudent Use of Antibiotics).

Seldom are these issues described in an evolutionary context, said Smith. "We're missing an opportunity to educate the public about the importance of evolutionary principles in our daily lives."

In conservation, evolutionary approaches are often disregarded because of the belief that evolution is beyond our ability to manage and too slow to be useful, according to a paper Smith co-authored in the journal Annual Review of Ecology, Evolution and Systematics (AREES).

That article, recently published online, also tackles applied evolution. It was co-authored by Carroll, University of Maine Biologist Michael Kinnison, Sharon Strauss--of the Department of Evolution and Ecology at University of California-Davis--and Trevon Fuller of UCLA's Tropical Research Institute. All are NSF-funded. Kinnison and Strauss are also co-authors on the Science paper.

Yet contemporary evolution--what scientists are observing now--happens on timescales of months to a few hundred years, and can influence conservation management outcomes, according to the AREES paper.

Considering the evolutionary potential and constraints of species is also essential to combat "evolutionary mismatch." This means the environment a species exists in, and the one it has evolved to exist in, no longer match.

Such disharmony can be "dire and costly," the authors write in Science, citing the increasingly sedentary lifestyles--and processed food diets--of modern humans. These lifestyles are linked with increasing rates of obesity, diabetes and cardiovascular disorders. Restoring our health requires greater physical activity and less refined carbohydrates: "Diets and activity levels closer to those of the past, to which we are better adapted," the Science paper said.

Implementing applied evolutionary principles often requires very careful thinking about social incentives, said Jørgensen. Public vaccination programs, for example, and pest control in crops often create tension between individual and public good.

Applied evolution, therefore, requires input from biologists, doctors, agriculturalists: "We're making a call for policy makers, decision-makers at all levels," to be involved, Jørgensen said.

Evolutionary biologists don't have all the answers, said Smith. And using applied evolution is not without risk. But we have reached a point "where we need to take risks in many cases," he said. "We can't just sit back and be overly conservative, or we're going to lose the game."

 

 

Fact or Fiction?: Oxytocin Is the “Love Hormone”

 

Love is complicated, and so is the purported molecule d’amour

Sep 8, 2014 By Gary Stix

A biochemical produced in the brain called oxytocin has entered popular culture in recent years as the “love,” “cuddle” or “bonding” hormone. That’s a lot to choose from.

Oxytocin plays a role in producing contractions at childbirth and in helping in lactation, but we’ve known that for more than a century. Experiments in the 1990s showed that it was instrumental in leading prairie voles, known for their monogamous behavior, to pick a lifelong mate. Later studies then demonstrated that the chemical contributes to trust and social interactions in various animals, including humans.

After the vole study, interest in the nine–amino acid peptide started to rise. In a TED talk economist Paul Zak called it “the moral molecule” because of its link to trust, empathy and prosperity.

The Internet DIY brain-makeover market then took up the meme.  Vero Labs of Daytona Beach, Fla., sells “Connekt” oxytocin spray for $79 that purports to “strengthen workplace bonds” and “increase positive self-awareness.” The company has also come out with a his-and-her“Attrakt” spray that mixes oxytocin with pheromones—chemical sex attractants that help mice get it on, but whose role in triggering mating behavior in humans is hotly disputed. (Researchers who study oxytocin warn prospective buyers away from these purchases, saying that long-term use in humans has not been studied.)

It is not all marketing and placebos, however. A substantive body of research suggests that oxytocin—and a related molecule called vasopressin—promote various types of social behavior. Participants in one study that involved playing an investment game forked over more money to an investment banker after taking a sniff. Oxytocin levels rose in a study of new parents as they became accustomed to living with their newborns. And trials are now under way to assess whether an oxytocin spray may help allay some of the social deficits of young children diagnosed with autism.

Oxytocin has another side to it that makes it something less than Love Potion No. 9. Recent research shows that it can intensify a negative memory of a social experience—such as the recollection of your boss yelling in your face in front of co-workers. It may even increase the likelihood of aggression and violence toward others who are not part of your social group.

Oxytocin without question has an influence on social dealings, but its effect may depend heavily on circumstance. The American Psychological Association’s Science Watch had two great quotes from scientists about oxytocin that caution against pigeonholing it as having any fixed role in governing social relationships:

“Oxytocin is not the love hormone,” says Larry Young of Emory University. “It’s tuning us into social information and allowing us to analyze it at higher resolution.”

And from Shelley Taylor of the University of California, Los Angeles:  “It’s never a good idea to map a psychological profile onto a hormone; they don’t have psychological profiles.”

That means that it may be awhile, if ever, before you are able to ratchet up that lovin’ feeling with a whiff from an inhaler—best to stick with the cabernet and the bubbly.

More on oxtyocin:

1. Be Mine Forever: Oxytocin May Help Build Long-Lasting Love

2. Oxytocin, the Love Hormone, Also Keeps People Apart

3. A Love–Hate Relationship?: "Feel-Good" Oxytocin May Have a Dark Side

4. Oxytocin May Relieve Some Autism

5. When is comfort most comforting? When you've got a specific Oxytocin gene!