Tag Archives: Energy

WISP – Re-programmable Microcontroller That Runs On Energy Harvested From Radio Waves

A new research initiative between the University of Washington’s Sensor Lab and the Technical University of Delft in the Netherlands has created a microprocessor that can power itself through stray radio waves and receive programmable updates in the same fashion. While the RISC-derived 16-bit microcontroller CPU is very weak compared to modern standards, it’s much more powerful than any other device that’s powered by ambient energy in the environment with no battery required.

The WISP 5 - Microchips and sensors run from radio wave's energy
The WISP 5 – Microchips and sensors run from radio wave’s energy

This battery-free system is equipped with a sensor and a microchip, which can be powered entirely by radio waves harvested from the air and is up to 10 times faster than similar ambient-powered devices. Best of all, in contrast to similar devices, it can also download executables, allowing it be reprogrammed or upgraded to newer version of firmware whenever needed. This has significant implications for the Internet of Things development and for ambient computing as a whole.

The variety of handheld, portable technology, and wearable gadgets available today is truly amazing. In order to make devices even more compact and thinner, manufacturers typically try to shrink their designs as much as possible. Unfortunately, device size is ultimately limited by the batteries, all of which have a certain capacity before they dry out and must be recharged again. It is a challenge for engineers and designers to balance battery life with function and aesthetics.

The project of radio wave-driven microcontroller is dubbed WISP, or Wireless Identification and Sensing Platform. RFID (CRFID) technology is an example of  WISP. In particular, WISP is capable of being powered passively by converting radio frequencies emitted by conventional RFID (radio frequency identification) readers into electrical power. The project’s latest accomplishment is the addition of Wisent (short for “wirelessly sent”), a faster and more reliable downstream communication-oriented protocol for CRFIDs that can tolerate fluctuations in operating power.

The WISP is constructed out of an open source, open architecture EPC Class 1 Generation 2 RFID tag that incorporates a fully programmable 16-bit microcontroller, in addition to any add-on sensors. It differs from ordinary RFID tags as it is programmable, and can be multi-functional. The team writes in their research paper,

The novelty of Wisent is its ability to change adaptively the frame length sent by the reader, based on the length throttling mechanism, to minimize the transfer times at varying channel conditions. Wisent enables wireless CRFID reprogramming, demonstrating the world’s first wirelessly reprogrammable CRFID.

App note: Implementation of a single-phase electronic watt-hour meter using the MSP430AFE2xx

Another energy meter from Texas Instruments using MSP430AFE2xx. (PDF)

This application report describes the implementation of a single-phase electronic electricity meter using the Texas Instruments MSP430AFE2xx metering processors. It includes the necessary information with regard to metrology software and hardware procedures for this single chip implementation.

App note: Implementation of a single-phase electronic watt-hour meter using the MSP430AFE2xx – [Link]

Researchers Developed Highly Durable Washable And Stretchable Solar Cells

Scientists of Japanese research institute RIKEN and the University of Tokyo have successfully developed a product that allows solar cells to continue to provide solar power after being washed, stretched and compressed. Takao Someya of Riken Center for Emergent Matter Science, a designated national R&D Institute in Japan, led the research team.

Washable and stretchable solar cell
Washable and stretchable solar cell

The research results were published in the journal Nature Energy and illustrated a photovoltaic material that could be used to make washable outer garments and wearable devices. The researchers say that the innovated solar cells will be a power source to low-power devices and can also be worn concurrently. This innovation might solve one of the biggest challenges of the Internet of Things (IoT), the requirement of a reliable power source to keep all devices connected.

The newly invented solar cells could power wearable devices that include health monitors and sensors for analyzing the heartbeat and body temperature. This could make prevention and early detection of potential medical problems possible. Though the concept of wearable solar cells is not unique, the previous wearable solar cell solutions suffered from the lack of one vital property i.e. long-term stability in air and water, including resistance to deformation.

The recent stretchable solar cell innovation has successfully achieved all of the most important features and is creating the way for the top-notch quality of modern wearable technology. The material on which their new device is based on is called PNTZ4T – a highly efficient polymer solar cell capable of small photon energy loss. The scientists deposited the device onto a parylene film which was then placed onto an acrylic-based elastomer. The construction method has proved to be particularly very durable.

The device produced 7.86 milliwatts per square meter based on a sunlight simulation of 100 milliwatts per square meter before considering resistance and durability. It showed the least decrease in efficiency when soaked in the water and when stretched. The efficiency decreased by only 5.4 percent and 20 percent respectively. Kenjiro Fukuda of RIKEN Center for Emergent Matter Science said,

We were very gratified to find that our device has great environmental stability while simultaneously having a good efficiency and mechanical robustness. We very much hope that these washable, lightweight and stretchable organic photovoltaic will open a new avenue for use as a long-term power source system for wearable sensors and other devices.

Bismuth Oxyiodide (BiOI)—A Non-toxic Alternative To Solar Cells

Bismuth is considered as a “green-element” and bismuth-based compounds are gaining attention as potentially non-toxic and defect-tolerant solar absorbers. The researchers of the University of Cambridge and the United States developed theoretical and experimental methods to show that bismuth, which sits next to lead (Pb) on the periodic table, can be used to make inexpensive solar cells.

Bismuth oxyiodide light absorbers
Bismuth oxyiodide light absorbers

The study suggests that solar cells including bismuth can have all the exceptional properties of lead-based solar cells but without any worries about toxicity. Another study by a different group discovered that bismuth-based solar cells have the ability to achieve a conversion efficiency of 22% which is comparable to the conversion efficiency of most advanced solar cell available in the market.

Many of the new materials recently investigated show limited photovoltaic performance. Bismuth Oxyiodide (BiOI) is one such compound and it is explored in detail through theory and experiment. Most of the solar cells commercially and domestically used are made from silicon (Si) which is efficient enough but has very low defect tolerance compared to bismuth oxyiodide. Low defect tolerance in silicon implies that the silicon needs to have very high levels of purity, making the production process energy-intensive.

Over the past several years researchers have been looking for an alternative to silicon for making solar cells cost effectively. The most promising group of these new materials are called hybrid lead halide perovskites. Unlike silicon, they don’t need such high purity levels. Hence, production is cheaper. But, the lead contained within perovskite solar cells represents a definite risk to all living beings and the environment. So, scientists are searching for non-toxic alternatives without compromising the performance.

Dr. Robert Hoye of Cambridge’s Cavendish Laboratory and Department of Materials Science & Metallurgy said,

We wanted to find out why defects don’t appear to affect the performance of lead-halide perovskite solar cells as much as they would in other materials.

The researchers are trying to figure out what’s special about the lead halide perovskites so that they can replicate their properties using non-toxic materials like bismuth.

Their research found that bismuth oxyiodide is as defect tolerant as lead halide perovskites are. Another interesting fact is, bismuth oxyiodide is stable in air for at least 197 days which is even better than some lead halide perovskite compounds. By sandwiching the bismuth oxyiodide between two oxide electrodes, the researchers successfully converted 80% of light to electrical charge.

DIY Home Energy Meter

A new tutorial by The DIY Life is for building a home energy meter that provides information about power consumption and cost estimates for the month.

Using Arduino and some other components you can build your own energy meter that measure the supply current to your home through a CT (current transformer), current, power, maximum power and kilowatt hours consumed. The cost of electricity used to date can be added and displayed easily.

arduino-energy-meter-high-consumption

Electronics you need to build this project:

  • Arduino Uno
  • LCD Shield / LCD Screen
  • CT – Talema AC1030
  • 56Ω Burden Resistor
  • 10µF Capacitor
  • 2 x 100K Divider Resistors

If you are not familiar with Arduino or LCDs you can check these articles by The DIY Life to learn more: getting started with Arduino, connect an LCD screen

First you have to build the current sensor by connecting the CT to the Arduino and setting a right voltage reference due to the Arduino 0-5V input range. As shown below, this is the way you should connect the CT to the Arduino.

energy-meter-wiring-diagram

This code should be uploaded to your Arduino to run the project. It already has a scaling factor that can be adjusted due to the components you choose in your circuit.If you don’t want to use or don’t have an LCD screen, you can also modify the sketch to output to the Arduino IDE’s serial window as described in this code.

For more information on how to choose different components, how to calibrate them, and to learn more details about wiring and coding, you should check this tutorial out.

The first number displayed is the instantaneous current followed by the instantaneous power. On the bottom line, the kilowatt hours used since reset and then the maximum recorded power since reset. Check the meter in action:

30A, PCB-level supply monitor has integrated 300 µΩ sense resistor

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>Designed to simplify board-level energy measurements, the LTC2947 power and energy monitor for 0V to 15V DC supply rails eliminates the need for an external sense resistor to measure current. by Graham Prophet @ edn-europe.com

Choosing a sense resistor, Linear says, is not an easy task, especially when dealing with high currents, where available sense resistors can dissipate too much power, occupy a lot of board space or have a large impact on measurement accuracy. The LTC2947 integrates a 300 µΩ temperature-compensated sense resistor to alleviate these concerns, providing users with a simple 24 mm² solution that provides up to 1.2% accurate energy readings at up to ±30A.

30A, PCB-level supply monitor has integrated 300 µΩ sense resistor – [Link]

Not a battery or a supercap, but a ‘thin laminate energy device’

160720edne-murata-umal_pr
Murata’s UMAL is a low-profile high capacity energy device. Designed to meet the demand for a slim high capacity energy source with a maintenance-free extended life cycle in wireless sensor nodes, the UMAL has charge/discharge and life-cycle characteristics superior to conventional secondary batteries. By Graham Prophet

The UMAL has a nominal voltage of 2.3 VDC, can supply 12 mAh with a maximum discharge current of 120 mA and is able to withstand load fluctuations. It has a low internal resistance of 200 mOhm and can operate over the temperature range of – 20C to + 70C.

Not a battery or a supercap, but a ‘thin laminate energy device’ – [Link]

Maximize the Energy from Long-Life Batteries

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by digikey.com:

Battery lifetime is a key consideration for the development of the wireless sensor nodes that will populate the Industrial Internet of Things (IIoT). In many applications, the sensor nodes will need to be installed in locations that are difficult to reach let alone service. The sensor nodes need to be autonomous in terms of energy because it is too costly and difficult to run power lines to them or to have maintenance workers replace batteries regularly.

Maximize the Energy from Long-Life Batteries – [Link]

ESP8266 mains energy monitor

pcb-in-case-600x306

Brian Dorey has designed a mains energy monitor based on ESP8266 that have sensors for the mains current, electric meter and gas meter.

As the new solar logger did not have this functionality we decided to design a new data-logger that would measure not only the mains current usage but also keep track of the electric meter and gas meter so we can easily see how much energy we are using in the house.
The new mains energy monitor was designed to be a standalone box that would be powered from the mains and have sensors for the mains current, electric meter and gas meter. As we didn’t want to run any more wires around the house we also decided to make it wireless connecting to our network over Wi-Fi.

ESP8266 mains energy monitor – [Link]

Nixie Tube Energy Meter

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John Whittington decided to build a Nixie tube energy meter to measure his house power consumption.

 An Arduino would be the microcontroller but I wanted the meter to provide some form of data stream for a web based energy history. To make it an IoT, I a paired ESP8266 with it. I used both together because the Arduino ADC has a better resolution and has been tried and tested.

Nixie Tube Energy Meter – [Link]