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Archive for June, 2012


DIY Rickshaw from a Trike

This is a clever adaptation of an “Adult Trike” commonly seen in retirement communities. Now you can safely give a small child a ride in this DIY Rickshaw. Now, to electrify it, with a solar canopy!

Author:urbanmx

This bike started as a way for me to take my daughter on a ride and still carry groceries or diapers. Never liked the original dark blue color but lived with it. We then had another baby and this bike sat outside for a few summers. I thought I could build a larger basket for it and take both of them on rides. But first a color change was needed. The bike felt like everything was a quarter turn too tight from the factory so a full strip down was necessary. I took a rough pad to parts for painting, cleaned them and let them sit in the sun before paint. Sprayed a few coats of paint and put them inside to dry. It’s hard to let things dry for a few days but I held strong and waited. Started putting it back together and was surprised how nice it was looking. This is becoming a totally different bike from a color change.

Built a simple wood basket out of plywood, trimmed it out and stained it. Next was the seat. Ripped some ¼” oak into 1” strips cut them all to length and primed and spray painted them. Lightly sanded the lifted grain off and did one more coat. Stapled them onto basket and borrowed some seat belts form our wagon. Nice and shiny and the white seat shouldn’t get too hot in the sun.

Time for a shake down. Rode to the store with the girls, everything was going good until I realized I had no way to carry stuff other than my girls. No problem I have a huge basket in my shed I will add to the bike. This basket is very big and very silver. It’s all I see when I look at the bike. Hopefully a little more spray paint will help tone it down. Ahh that’s better. One last thing for this project an umbrella at a yard sale should add the finishing touch and turn this once ugly bicycle into a full on rickshaw.

Hope you all enjoy the pictures it has been a fun project. I even get some thumbs up from people when we go on tour.

Instructions

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Lovelock says oops on Global Warming

James Lovelock, father of the Global Warming theory and the Gaia Theory says he and Al Gore were incorrect with their doomsday predictions. Many millions of dollars have been spent on “preventing” the catastrophic stuff that was mistakenly forecasted. It’s still critical to keep our water and air clean in order to live a healthy life, but we are not at risk of flooding our lowlands or turning our southern climates into deserts as was claimed by Al Gore, Michael Moore, and others. The political policies based on bad data need to be readjusted in a practical manner.

“One thing that being a scientist has taught me is that you can never be certain about anything. You never know the truth. You can only approach it and hope to get a bit nearer to it each time. You iterate towards the truth. You don’t know it.”

http://www.torontosun.com/2012/06/22/green-drivel

http://www.theregister.co.uk/2012/04/24/lovelock_clangers/

http://worldnews.msnbc.msn.com/_news/2012/04/23/11144098-gaia-scientist-james-lovelock-i-was-alarmist-about-climate-change?lite

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Emergency power for Ham Field Day

My friend Dean and I worked Ham Radio Field Day (WA4USN) on the USS Yorktown (CV10). Due to various issues, all 3 generators failed, so Dean and I hooked up his big deep cycle battery and a 400 watt inverter, and kept the radios going for the 20 hours or so left of field day. Next year we hope to bring solar panels, and not use generators at all.

Field Day Pics

During field day, one of the guys made a contact. When we logged his call sign, a message popped up saying “I am the creator of this software”. That was awesome!

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Off Grid Power & Communications

As a Ham Radio operator (KK4HFJ), and with interests in disaster communications and weather monitoring / reporting (Skywarn), I have added sections on off grid ham radio and our diy amp / watt hour meter (and are working on the off grid weather station and packet radio BBS projects) to our DIY Solar ebook package. We have also cut the prices by 50% (now $20) to help raise funds for Emergency Communications and Weather Warning projects.

The weather station will be a portable emergency weather station (in kit form) that beacons weather data on shortwave frequencies, and accessible as a radio Bulletin Board System (BBS, pre-internet) and internet (if available).

Everything you need to know to design, build and maintain your own off grid power system is included in this package. It’s the culmination of our years of electronics and power training and off grid living experience.

http://www.green-trust.org/products/

For DIY info on these projects, see http://arduinotronics.blogspot.com

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Wireless Solar Charging Made Easier

19 June 2012—Anybody with a smartphone dreads the low-battery warning that initiates a mad search for an electrical outlet. But engineers at Princeton University are developing technology that could lead to widespread wireless charging stations for all our electronics. Along the way, this technology could also help build better sensors to monitor the health of both humans and buildings.

Wireless chargers operate through inductive or capacitive power transfer. An alternating current creates an oscillating electrical or magnetic field, which induces power at the receiver. “We’re looking for an opportunity to create ubiquitous charging stations,” says Naveen Verma, an assistant professor of electrical engineering at Princeton.

Verma and his team presented the work last week at the IEEE Symposia on VLSI Technology and Circuits, in Hawaii. The research focuses on using the same material—thin films of amorphous silicon—both to make solar cells and, for the first time, to build circuits to handle the electricity the solar cells produce. The combined solar cells and circuitry could be made on large sheets of plastic that could be molded or wrapped around everyday objects, from buildings to patio umbrellas. Amorphous silicon has its limitations. For one, it’s not as efficient at converting light to electricity as crystalline silicon is. But unlike crystalline silicon, it can be processed at relatively low temperatures, allowing production over large areas on plastic substrates. Amorphous silicon also produces transistors with much lower performance than crystalline silicon. The reduced speeds result in low-quality inductors, which are typically a key component in creating the oscillating fields used in wireless power transfer. What’s more, it is usually possible to build only n -type thin-film transistor (TFT) devices, but not both n- and p-type at the same time, as needed in the complementary logic of computers.

So Verma’s team designed a circuit containing two solar cells, capacitors, and n-type TFTs, skipping the p-type TFTs and inductor. The TFTs switch the current so it flows to the capacitors first from one solar cell and then the other (which is wired in reverse), thus turning the direct current produced by the cells to the desired alternating current.

Verma says the charging system can provide a device with up to 120 microwatts of power at a transfer efficiency of up to 22 percent under indoor lighting. An iPad, which uses power in the tens of milliwatts, wouldn’t benefit much from that, but there should be ways to increase the charger’s capability. A larger energy-harvesting surface can provide more power, and larger capacitors raise both power and transfer efficiency; increasing their area from 5 by 5 centimeters to 10 by 10 cm increases power by a factor of four. Verma is also interested in replacing the amorphous silicon circuits with metal oxide semiconductors, such as zinc oxide, which may work better and is compatible with the silicon processing.

In the meantime, he says, “there are a lot of devices that consume very little average power.” Some medical sensors, such as those worn on the body to monitor heart rates or other signals, need only a few tens of microwatts. And in other research presented at the conference, Verma and his colleagues propose combining thin-film solar cells with thin-film electronic circuitry for power management, readout, processing, and communications in a new type of structural sensor for buildings.

Today, sensors for monitoring strain in buildings and bridges often consist of an optical fiber connected to a detector. If a bridge bends more than a certain amount, that bends the fiber, which alters the light hitting a detector at one end. Verma would like to replace that design—which senses strain in only one dimension—with an array of sensors, powered by photovoltaics. “The kind of sensors we’re envisioning are much more functionally diverse,” he says. “This technology provides sensing capability on a scale that no technology we have now could provide.” He’s hoping to install a prototype of such a system on a bridge on the Princeton campus.
About the Author

Neil Savage, based in Lowell, Mass., writes about strange semiconductors and amazing optoelectronics. In the April 2012 issue of IEEE Spectrum, he reported on molybdenum disulfide, a potential rival to graphene in nanoelectronics.

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Gardening for Nutrition

A lot of folks have gardens. It’s a wise thing to do, especially in this economy. However, what are you growing? Are you growing foods because of taste, tradition, or are you considering the food value of what you are growing. For instance, beets are very low in nutritional value, but the leaves are very high. Are you using the leaves?

Certain combinations of food act as catalysts for the nutrition of other foods. Adding dried Moringa leaves to your recipes can really spike the food value of the dish you are preparing, often without knowledge of it’s inclusion.

A balanced diet contains legumes, cereal, leafy greens, and some root crops (sweet potato), even if no meat is available. The combination works with each other, adding benefits that one can not provide alone.

I highly recommend you check out the following free resources, and start improving your health by eating better, and gaining the value of the exercise gardening provides.

A (sub) tropical guide to year round vegetable gardening (greenhouses in cold climates qualify)


Preventing micronutrient malnutrition: a guide to food-based approaches…

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Zeolite Stores Thermal Energy For Unlimited Amount of Time

By Tessel Renzenbrink

Scientists of the German Fraunhofer Institute have harnessed a natural phenomenon to store heat indefinitely and without energy loss.

Zeolite is a mineral that can store up to four times more heat than water. And what’s better, unlike water which gradually cools off, zeolite retains a hundred percent of the heat for an unlimited amount of time.

Zeolite – which means ‘boiling stone’ in Greek- was named for its peculiar properties. Zeolite is extremely porous. So much so, that a gram of the stuff has a surface area of a 1000 square meters (10,764 sq ft). When water comes into contact with zeolite it is bound to its surface by means of a chemical reaction which generates heat. Reversely, when heat is applied the water is removed from the surface, generating large amounts of steam.

The transference of heat to the material does not cause its temperature to rise. Instead, the energy is stored as a potential to adsorb water. The Fraunhofer scientists used these particular properties to turn zeolite into a thermal storage system. They created a storage device and filled it with zeolite pellets. To charge the pellets, they exposed them to heat. To retrieve the energy they simply added water.

The discovery can give a much anticipated boost to thermal storage. Power plants and many industrial processes produce heat as a byproduct. Up to fifty percent of the initial energy input is released as heat.

But heat is difficult to store. The most common form of thermal storage is in huge insulated water tanks. But water can only retain heat for a short period of time which makes it unsuitable for long distance transport. Therefore, in most processes heat is released into the environment unused.

Although the unique properties of zeolite were well known, until now, no one was able to turn it into a working thermal storage system. The German researchers first tested their system with small quantities zeolite to determine whether the material would remain stable over multiple charge and discharge cycles. And it did. Even after thousands of cycles.

Now they’ve built an up-scaled version with a storage volume of 750 liters which they’re testing under realistic conditions.

Read more at http://www.igb.fraunhofer.de

Additional resources including DIY info:


Utilization of natural zeolites for solar energy storage

SOLAR ENERGY APPLICATION OF NATURAL ZEOLITES

Solar Zeolite Ice Maker

EVALUATION OF A ZEOLITE-WATER SOLAR ADSORPTION REFRIGERATOR

Space Heating and Domestic Hot Water

DIY SOLAR ADSORPTION-DESORPTION REFRIGERATOR

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Capacity, the Key to Battery Runtime

A look at emerging rapid-test technologies for deep-cycle lead-acid batteries
By Isidor Buchmann, Cadex Electronics Inc.

The secret of battery runtime lies in the capacity. Capacity defines the energy a battery can hold. The definition for capacity is usually given in ampere-hours (Ah); it specifies the elapsed time when discharging a battery at a calibrated current to the end-of-discharge voltage. Portable batteries commonly use a one-hour discharge; larger batteries are rated at either a 5 or 20-hour discharge.

Lead acid batteries come in two basic architectures: deep cycle and starter types. The deep cycle battery is designed for maximum capacity and high cycle count. This is achieved by installing thick lead plates. Typical applications are golf carts, wheelchairs, people movers, scissor lifts and RVs. Starter batteries, in comparison, are made for maximum CCA (cold cranking amp). The battery maker obtains this by adding extra plates to get a large surface area for maximum conductivity. Capacity and deep cycling are less important for automotive because the battery is being recharged while driving. If continuously cycled, the thin lead plates of the starter battery would wear-down rather quickly. As a rule of thumb, the heavier the battery, the more lead it contains and the longer it will last.

What is the difference between Capacity and CCA?
The characteristics of the lead acid battery can best be explained by making capacity responsible for energy and CCA for delivery. Capacity and CCA do not age at the same pace. The CCA tends to stay high through most of the battery’s life, and then drops quickly towards the end. This often leaves us stranded when all of a sudden the car won’t start in the morning. In comparison, capacity decreases gradually. A new battery is designed to deliver 100% of its rated capacity. As the battery ages, the capacity steadily drops and it should be replaced when the reading falls below 70%. The reader will soon realize that capacity measurement is a more reliable state-of-health indicator than CCA.

Let’s look at the aging mechanism of capacity and CCA with graphic illustrations. Figure 1 shows two lead acid batteries, one with high capacity and one that has aged. The build-up of so-called “rock content” as part of aging robs the battery of usable energy although it may still provide good cranking power. Figure 2 illustrates a battery with high and low CCA by simulating free-flowing and restricted taps.

The third criterion of battery runtime is state-of-charge (SoC). The battery capacity is always measured on a fully charged battery and the most simplistic method of estimating SoC is reading the open terminal voltage (OTV). This approach is accurate if the battery has rested for at least four hours after charge or after applying a load. The rather long rest period is the required recovery time to pacify a battery when disturbed. The reader should also be aware that different plates composition alter the OTV reading. Calcium raises the voltage by 5-8%, affecting SoC estimation. Calcium is an additive that helps in making the battery maintenance-free.

Battery rapid-test methods
Battery capacity is commonly measured by applying a full discharge. While this method provides accurate readings, it is cumbersome, time consuming and wears the battery down unnecessarily. During the last 15 years, several rapid-test methods have emerged that eliminate the need for discharge, so the manufacturers claim. Introduced in 1992, AC conductance became popular in measuring conductance, from which CCA is estimated. This non-invasive method was hailed as a major breakthrough because the test only takes a few seconds and the instrument stays cool. Unfortunately, AC conductance is unable to read capacity and is of limited use for deep cycle batteries.

During the last five years, critical progress has been made towards capacity estimations. Cadex has developed a battery rapid-tester based on multi-model electrochemical impedance spectroscopy (Spectro™). The Spectro CA-12 injects 24 frequencies ranging from 20-2,000 Hertz. The signals are regulated at 10mV to stay within the thermal battery voltage of lead acid. The 24 slices from the frequency excitations are compared and the minute nuances analyzed. The instrument completes 40 million transactions during the short 15-second test.

Electrochemical impedance spectroscopy (EIS) is not new. Equipment using this technology has been in use for decades. A full-fledged EIS requires dedicated instruments and a computer to analyze the data. The set-up is expensive, requires trained staff for analysis and is so large that the machinery is moved on wheels. Furthermore, long calculation times make the system unsuitable for commercial use. The Spectro CA-12 has solved these problems by using powerful digital signal processors, but the heart of the engine lies in the patented algorithm.

What are typical battery problems?
Let’s look at the most common battery problems and evaluate how modern battery rapid-testers can detect these deficiencies. One can immediately see the benefit of knowing the capacity.

Low charge. A low charge reduces the drive power and the battery appears weak. Checking a low-charge battery with a discharge unit will show low capacity. Rapid testers such as the Spectro CA-12 are able to measure the capacity with a SoC as low as 40%. If lower, the instrument will prompt to charge and retest.

Low capacity. This low capacity battery will likely have good conductivity and strong torque. The voltage checks out fine and everything appears normal except the short runtime. Knowing the capacity on an aging deep cycle battery is very important because it’s the best indication when a battery should be replaced.

Mismatched set. Batteries do not age at an equal pace. Like the links of a chain, the battery with the lowest capacity will govern the runtime. Battery testers reading capacity can identify low performers and allow a timely replacement. The high performers can be regrouped for continued service.

As encouraging as battery rapid testing may be, the reader needs to be reminded that rapid-testers, such as the Spectro CA-12, are not universal instruments capable of measuring the capacity of any battery that will come along; they need a battery-specific matrix as a reference. On purchase of such a unit, the instrument includes one or several matrices that are automatically matched with the selected battery. Cadex is in the process of expanding the matrix library to eventually include all major battery types.

In time, measuring battery performance through non-invasive means will become the acceptable standard, making discharge methods redundant. Typical applications are: checking batteries to reduce false warranty returns, preventing unexpected downtime by assessing battery state-of-health before a breakdown occurs, and improving the reliability of battery operated rental equipment.

Designers of battery rapid-test methods tend to be overly optimists and create targets that may not be achievable outside the laboratory. However, multi-model electrochemical impedance spectroscopy represents a great leap forward and opens the door to an entirely new way of battery testing.

About the Author

Isidor Buchmann, founder and CEO of Cadex Electronics Inc., has studied the behavior of rechargeable batteries in practical, everyday applications for two decades. As an award-winning author of many articles and books on the subject, Mr. Buchmann has delivered battery-related technical papers around the world.

Cadex Electronics Inc. is a Canadian company specializing in the design and manufacturing of advanced battery testing instruments. For product information please visit www.cadex.com

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