Author Archives: Andi

Replace Your Hall Devices with LVDT-On-PCB

The use of solid-state devices such as magnetic sensors is very popular when necessary to sense position, velocity or directional movement. As they are non-contact and offer wear-free operation, electronics designers prefer to select them for their design. For example, the robust design of sealed Hall Effect devices make them immune to vibration, dust and water, offering a low maintenance solution for the user.

Automotive systems mainly use magnetic sensors for sensing speed, distance and position. For example, the angular position of crankshafts decides the proper firing angle of the spark plugs, air-bag control depends on position of car seats and seat belts and wheel speed detection is necessary for ABS or anti-lock braking system.

Magnetic sensors typically respond to a wide range of magnetic fields and therefore, they are used in a variety of different applications. Hall-effect sensors respond to magnetic field density around them, while generating a proportional electrical output signal. Magnetic fields show two important characteristics, the flux density and the polarity. When activated beyond a preset threshold, the hall-effect sensor develops a voltage linearly proportional to the flux density impinging upon it. However, hall-effect sensors are susceptible to external magnetic fields and/or the presence of metal objects nearby.

Replacing hall-effect sensors with LVDT or Linear Variable Differential Transformers offers superior immunity to noise and interference, while improving the sensitivity tremendously. By using inductive technology, designers avoid the use of magnets, thereby improving immunity to interferences. Now, with LVDT-on-PCB, the inductive sensor IC based on LVDT makes these sensors suitable for use in the automotive and industrial fields.

The device, LVDT-on-PCB, is suitable for several applications related to industrial automation and control systems. Among these are specific applications such as linear displacement measurement. Therefore, such sensors simplify sensing of fluid levels, gear position for transmission actuator positioning and proximity detection of brake lamp switch. Additionally, LVDT-on-PCB sensors are also useful in sensing angular motion such as in rotary controls and measuring pedal positions, rotating shaft positions and robotic arm positions.

As the LVDT senses without making contact, the reliability offered is high. For example, the associated IC LX3301A, from Microsemi, has an embedded 32-bit processing engine running on an internal oscillator of frequency range between 1 and 5 MHz, along with a 12 KB program memory. It offers two sensor input channels with integrated demodulators and two 13-bit ADCs with sample rates up to 2 KHz. The user can save their configuration in the user-programmable non-volatile configuration memory of size 16×16 bits.

The LX3301A processes signals that the inductive sensors generate. As the inductive sensors work on LVDT principles, the IC includes an integrated exciter to drive the PCB-based sensor coils of low inductance. A matched analog channel pair processes the sensor signals as a pair of sine/cosine waves, thereby rejecting the noise sources both internal to and external to the sensor assembly.

You can use the LX3301A for measuring displacement such as linear and/or angular/rotation and proximity in electromechanical systems. The resolution offered is excellent, for example, in applications involving 360-degree rotation, the device can achieve a measurement resolution up to or less than 0.5-degree. You can retain the configuration and calibrations for the sensor system in its internal EEPROM.

Protecting Pedestrians Using Ultrasound Techniques

With vehicular traffic increasing on the roads, pedestrians are shifting to the status of endangered species. Frequent news reports of pedestrians falling victims to collisions with motor vehicles bear testimony to the statement. Now, researchers want to provide a remedy. At the Frankfurt University of Applied Sciences or FRA-UAS, researchers have developed a pedestrian detection sensor that can differentiate a human being from among inanimate matter.

At FRA-UAS, Professors Andreas Pech and Peter Nauth have developed the pedestrian detection system utilizing highly sensitive and efficient ultrasonic sensors. It can discriminate a human being from an object in areas where a collision is likely. Typically, vehicles use such highly cost-effective ultrasonic sensors at their rear to help in parking. The researchers have added an algorithm for recognizing patterns from the signals coming from these sensors. The algorithm, the actual innovation from the researchers, generates a situational analysis within half of a second. This is then used to activate specific protection systems.

In a collision situation, there can be two possibilities. The first could be a vehicle-to-vehicle collision, where the system activates airbags and belt pre-tensioners as it detects an imminent collision with another vehicle. However, if the system determines that the collision situation involves a pedestrian and not a vehicle, it initiates measures that will reduce the impact. These measures could vary, such as, heightening the bonnet to mitigate the impact, providing an exterior airbag to be deployed prior to collision or even reducing the rigidity of the body of the vehicle.

According to the researchers, this pedestrian detection system is relatively more cost-effective in comparison to other systems available in the market. It is possible to retrofit this system even in lower priced vehicles. Moreover, such a pedestrian detection system is also useful in other areas of application. For example, in case of a building fire, where smoke detectors trigger fire alarms, the pedestrian detection system from FRA-UAS can help to locate human beings trapped inside the burning house or apartment.

Application of such a pedestrian detection system can be seen in the crosswalk flasher system installed at the Weaver Lake Elementary School in Maple Grove, Minnesota. The school added the automatic detection system to increase the safety of children who occasionally forget to push the button to activate a flashing beacon before starting to cross the road. The pedestrian detection system uses ultrasonic sensors for detecting the presence of pedestrians waiting at the curb and automatically activates a flashing beacon to alert the approaching vehicles to the presence of the pedestrian.

Ultrasonic detectors emit sound waves of frequency ranging beyond the hearing capabilities of humans. In the presence of moving pedestrians or vehicles, part of the transmitted sound waves reflects back to the receiver. The associated electronics computes the distance and speed of the object from the time and strength of the reflected signal. Ultrasonic detectors detect objects as far away as 30 feet.

The amount of sound energy reflected from the pedestrian depends on the nature of clothes the person is wearing. It also depends on the temperature, pressure, humidity and wind speed at the location.

Long Lasting Solar Aqueous Flow Battery

Yiying Wu, Professor of chemistry and biochemistry at the Ohio State University, Ohio State, and his team has combined a solar cell and a battery to form a single device. A novel solar panel on top of the battery captures energy from sunlight. The battery is able to source 20% of its energy from sunlight. Although the design is pending a patent, the researchers have published their findings in the Journal of the American Chemical Society.

Tests conducted by the researchers show that their solar flow battery produces the same output as a lithium-iodine battery does, even when the solar flow battery had a lower charge. They charged and discharged both batteries 25 times. Each time, they discharged the batteries until the terminal voltage fell to 3.3 volts. Conventional lithium-iodine batteries have high energy densities, approximately twice that of lithium-ion batteries. Hence, lithium-iodine batteries have the potential to fulfill the needs of long-driving-ranged electric vehicles.

In the experiments, lithium-iodine batteries had to be charged up to 3.6 volts, before they could be discharged down to 3.3 volts. Comparatively, solar flow batteries produced the same energy output with a charge of only up to 2.9 volts, as the solar panel made up the difference in their terminal voltage. That represents an energy saving of nearly 20 percent.

The team has made two changes to their earlier design from 2014. The solar panel, which was a mesh earlier, is now a solid sheet. Additionally, they now use a water-based electrolyte within their battery. With water circulating within the battery, the team has assigned the new design to an emerging class called the aqueous flow batteries. Yiying Wu claims their solar battery with aqueous flow is the first of its kind.

The water-based solar battery is compatible with the current battery technology and is easy to maintain. The environmentally friendly technology can be very easily integrated with existing technology.

According to Wu, the design of the solar flow battery is adaptable and can be applied to grid-scale solar energy conversion and storage. In the future, electric vehicles might also benefit from the electrolytic fuels used in the solar flow batteries.

In the earlier design, Wu and his team had designed the solar panel with a titanium mesh, which passed air to the battery. The new design using water based electrolyte does not require air to function, and hence, the solar panel is now a solid sheet.

The solar panel has a red dye so that it can tune in to a specific range of wavelengths of solar light to capture and convert to electrons. The team calls their solar panel dye-sensitized and the electrons it produces serve to supplement the energy stored within the lithium-iodine battery.

The electrolyte within the battery helps to absorb the electrons produced by the solar panel. A typical electrolyte is actually part solvent and part salt. Earlier, the researchers had used the organic solvent dimethyl sulphoxide to dissolve the salt lithium perchlorate. They have now changed over to lithium iodide salt dissolved in water, as this is more eco-friendly and offers higher energy storage capacity at lower cost.

PIR Sensor: Let Raspberry Pi Guard your Home

With a versatile platform such as the Raspberry Pi or RBPi, prototyping a project is very simple. The scale does not matter for you can start with a single blinking LED and move on to complex quad copters. If you have the necessary components, simply add a little amount of imagination, and RBPi can work wonders for you.

A practical use for the RBPi is to sense the surrounding environment. Not only is this interesting, but also gathering this data is useful in myriad ways. For example, a weather station uses different sensors to measure pressure, humidity, wind speed and temperature. The main objective in recording and manipulating such data is to predict future weather conditions. Anyone technically savvy can store this data and manipulate it to produce tables and graphs for importing into other applications or projects.

Using a PIR or Passive Infra-Red sensor with an RBPi can be an effective guard for your home. These inexpensive sensors are used with motion activated air fresheners from which, you can easily harvest a couple for building this project. The PIR and RBPi combination can act as an effective burglar alarm in homes and offices.

The PIR sensor effectively sends out a beam of infrared light into the area that it is monitoring. As long as there is no movement in the area, the beam remains undisturbed. However, the slightest movement causes the beam to change, which the PIR sensor can sense. The PIR sensor, when connected to the RBPi, sends it a signal once it detects movement. The RBPi responds to this signal in a manner defined by its program.

For this project, the PIR sensor is set up to watch over an area for any movement. As soon as it detects movement, it triggers the RBPi, which responds by capturing a picture of the event on its camera, including recording a 10-second video at a resolution of 640 x 480 pixels.

Additionally, the RBPi will send out a text message to the owner’s phone, thereby alerting the user of an intruder or whatever that triggered the event. The text message includes the picture and the video. After sending the text, the RBPi will wait for 30 seconds before resuming its watchful stance.

Apart from being an effective burglar alarm, you can use this combination of PIR sensor and RBPi with its camera in many innovative ways. For example, those who like to study birds and their habitat, can set it up near the nest to record the coming and goings of the parent birds.

Using a text message to alert the user is effective, as all phones are capable of receiving SMS. Other methods using emails or tweets usually rely on 3G or Wi-Fi coverage and may not be always useable. Additionally, you can use several alerts from the project simultaneously. The RBPi stores the pictures and video it captures in its memory. You can retrieve them later via any means convenient.

To set up, install the OS in the RBPi, enable the camera via raspi-config and test its working. Use the command “raspistill -o test.jpg” for testing. This produces an image file by the name test.jpg.

Why Do ICs Need Bypass Capacitors?

Any electronic design engineer will vouch for the necessity of supplementing integrated circuits on their PCB with bypass capacitors, although they may not understand the reason to do so very well. As a rule of thumb, engineers provide every IC with a 0.1µF ceramic capacitor next to its power pins in each circuit board they design. Along with proper PCB layout techniques, adding a bypass capacitor improves circuit performance and maximizes the efficacy of the ICs.

The trouble lies with transition currents. Circuits handling digital signals produce rapid transitions when their signals switch states. When digital circuits output a high state, the signal voltage is very close to the supply voltage. When they output a low state, the signal voltage reaches very near the ground voltage. When transiting from a low to high or a high to low, the voltage swing from supply to ground or from ground to supply, causes a transient current to be drawn from the supply.

Usually, power to an electronic circuit on a PCB is fed at a single point and traces on the PCB carry this power to each IC. Traces on the PCB have their own parasitic inductance, which, when coupled with the source impedance of the power supply, react to transient currents by creating voltage transients.

The trouble aggravates when ICs have to drive low-resistance or high-capacitance loads. The low-resistance demands high currents when the digital state changes from low to high. Again, when the digital state changes from high to low, there is a demand for the load current to reduce suddenly. However, according to Lenz’s Law, an induced current will flow such as to oppose the change that produced it.

The net effect of transient currents and the parasitic inductance of PCB traces and wires are to create high-magnitude voltage transients, ringing or severe oscillations in the power lines. This can lead to suboptimal circuit performance or even to system failure. Engineers at Texas Instruments have demonstrated an improperly bypassed line driver IC switching at 33MHz can induce ringing amplitude of the order of 2V peak-to-peak on a 5V power rail.

Placing a 0.1µF ceramic capacitor close to the IC power pins improves the situation, because capacitors store charge. Placing the bypass capacitor close to the IC allows low resistance and series inductance. The bypass capacitor is therefore in a better situation to supply or absorb the transients on the PCB traces, which have a comparatively larger resistance and series inductance.

Although engineers refer to such components as both bypass and decoupling capacitors, there is a subtle distinction between the two terms. Decoupling refers to the amount by which one part of the circuit influences another. Bypassing provides a low-impedance path allowing noise to pass by an IC on its way to ground. A capacitor, placed close to the IC supply pins, accomplishes both decoupling and bypassing. However, a decoupling capacitor has an additional task. It blocks the DC component of a signal and prevents it from traveling through to the next part of the circuit, while allowing the AC component little or no resistance at all.

Raspberry Pi Rover to Mine Water on Mars

Water is an essential chemical for sustaining any sort of life on the planet Earth. From what knowledge space explorations have provided us so far, this is true for life elsewhere in the universe as well, but there are deviations. Mars being our closest neighboring planet, it is only natural for us to try to locate water there. Additionally, with the human population on our home planet close to its saturation point, it is essential we plan to distribute the excess populace on nearby planets. For this, we need to make sure of the presence of water there or at least, the possibility of generating it simply and easily.

Collaboration between the Gilmour Space Technologies, Australia and the Singapore University of Technology and Design is exploring the Mars Aqua Retrieval System or MARS. This is a prototype for harvesting water from the soil of the Red Planet. The team has built the prospecting rover for less than $10,000. Based on the famous Single Board Computer, the Raspberry Pi and an Arduino unit, the rover uses microwaves to heat up and release the frozen water present in the Martian soil.

Although designed to work on Earth, the proof of the concept takes its basic idea from the discoveries made so far by Curiosity and the Phoenix Mars Lander. These extraordinary rovers have indicated the presence of water on the Red Planet. This water either is in non-liquid forms such as ice or buried in its soil. Engineers have designed the rover MARS to extract water from the Martial soil, collect and store it. With NASA recently declaring the presence of running water on Mars, project MARS has taken on an even greater importance.

Detailed documentation of the project indicates scientists considered various methods for each step of the process. The final concept involved separating and collecting water using microwaves and a cold trap. According to tests conducted by the team, they claim to have collected four grams of water from frozen soil in four minutes.

The process of water collection involves cycles of locating the MARS system using its two powered wheels to move to the target area, lowering a microwave unit over the ground and then heating the area for about 20 minutes. This releases steam from the Red soil and it enters a collection pipe leading to a condenser bag, where the steam condenses into water that finally drips into a collection box. The entire process is similar to distillation in any chemistry laboratory.

Although NASA provided only a meager budget of $10,000, the team has managed to create a prototype that presently functions satisfactorily on Earth. The two SBCs the Arduino and the Raspberry Pi in MARS control the locomotion and timing, the arm movements and the on/off switching of the microwave. The prototype is able to withstand 30% of the pressure and temperature conditions present on Mars.

According to Adam Gilmour, CEO of Gilmour Space, the US space agency has reacted favorably to the details of the MARS design sent to NASA. Although, in its present form, the prototype is unlikely to leave Earth’s atmosphere, MARS will be available for public view at the Gilmour Space Museum, north of Australia’s Gold Coast.

Keep Your Fish Happy with a Raspberry Pi

People who keep fish in aquariums at home know it is important to feed them timely and to keep their habitat clean. Trouble starts when the owner has to leave home for a few days and cannot find a knowledgeable caretaker to take care of the pets. Cabe Atwell tried to solve the problem he faced in an ingenious way – by using the power of the Internet.

Cabe had an automatic fish feeder, but he also enlisted the services of a friend to keep an eye on her goldfish, the friend was not sure of what was required and the automatic fish feeder broke down. Fortunately, the losses were not fatal, but Goldie the goldfish grew to double her size because of overfeeding. This led Cabe to work on a system to allow watching and feeding the pet over the Internet.

Cabe wanted a system that would allow seeing the fish in real time, anytime, by moving a camera around the tank. The next requirement was sensing the tank water temperature and cutting off the power to the tank bubbler and air filters, if necessary. It was also necessary to feed the fish manually, and above all, to do this through a network and ultimately, via the Internet.

Cabe’s research led to the conclusion that a Single Board Computer such as the Raspberry Pi or RBPi and a Pi camera would be most suitable for seeing the fish via the internet. For the other features, an Arduino Uno was more appropriate.

Accordingly, Cabe selected two small Nema 17 mount stepper motors, available on Adafruit, for the driver components. The motor controls came from an Arduino Motor Shield, which made it simpler to drive the motors. Cabe designated one motor for allowing movements in two directions, while the other rotated the food container to dump fish food into the water.

The fish feeder was a modification of the original malfunctioning feeder. It consisted of a drum to hold the fish food. When rotated completely around, a simple trap door opens briefly to let a small amount of feed.

To keep the camera motor traveling too far, Cabe incorporated limit switches in both directions. The limit switches were placed in position using rare-earth magnets, which allowed easy adjustments for the movement range. A surplus belt driven motion platform provided an affordable arrangement for viewing the entire length of the tank.

For sensing the water temperature, a waterproof digital temperature sensor was the most suitable – DS18B20. Although fresh-water fishes are more tolerant of water temperature variations, loss of air-conditioning or heating arrangement can lead to the tank water becoming too hot or cold for the comfort of its occupants.

For the video stream, Cabe settled on VLC since it was easier to use. VLC offered the maximum resolution of 640×480 pixels at 15 frames per second, which Cabe found adequate for keeping a tab on the fish. A simple AC relay took care of feeding power to the air filters and bubbler.

For the future, Cabe wants a better AC control and more sensors for measuring the pH, ammonia and nitrate levels in the water.

How Does Switching Affect Semiconductors?

Even though ICs rule the world of electronics, the transistor does all the work. Within each IC are millions upon millions of transistors perpetually switching on and off so that the IC can carry out its intended functions. Even if one of the multitudes of transistors were to stop switching, the IC could lose part or all of its functionality.

Circuits handling digital signals most often use transistors to switch from a high state to a low state and vice versa. It is usual to call a circuit point as being in a high state if the voltage at that point is close to the supply voltage. If the circuit point is closer to the ground or zero voltage, we generally call it as being at a low state. The time taken for the transistor to switch from a high to a low state or vice versa is its switching rate. While the transistor does not expend much energy when at either the low or the high state, the same cannot be said for the time when it is actually switching.

Under ideal conditions, a transistor should switch instantaneously. That means the transistor should take zero seconds to change its state. However, ideal conditions do not happen in reality and the transistor takes a finite time, however small, to actually switch over.

Transistors are made of semiconductor material and each junction has a finite capacitance and resistance. Junction capacitances store energy and the combination of resistance and capacitance acts to slow down switching – the capacitance must fill up or empty itself before the transistor can flip. The rate at which the capacitance fills up or empties itself depends on the junction resistance.

The situation gets worse as the switching frequency goes up. As the transistor is driven to toggle faster and faster, the junction capacitance may not get enough time to discharge or charge up fully. That defines the maximum switching rate the transistor can achieve.

Semiconductor manufacturers use various methods to reduce junction capacitances and resistances to induce these special semiconductors switch faster. Although modern semiconductors (transistors and diodes) are capable of switching at MHz or GHz scales, the cumulative effect of the tiny switching losses add up to increase the junction temperature.

Power is the product of voltage and current. When a semiconductor is in a high state, although the voltage is high, the current is negligible and consequently, the power drawn from the supply is negligible. When the semiconductor is a low state, its voltage is close to the ground level and the product of current and voltage is again negligible.

However, during switching, when the voltage is somewhere in-between the supply and ground levels, the current drawn also increases. That makes the product of voltage and current have a significant value and the semiconductor generates heat because of the power consumption. With higher frequencies, this happens more frequently and the heat accumulates to produce higher junction temperature.

If the natural process of heat dissipation can remove the accumulated heat, the semiconductor soon reaches a steady temperature. Else, heatsinks and or forced cooling methods are necessary to remove the heat accumulated.

A New 6 Axis Motion Sensor

Except for professional photographers using tripods, most people now use the camera within their smartphones to capture images of their surroundings. More often, unless your hands are exceptionally steady, the captured image is somewhat blurred. The act of holding the smartphone, aiming it properly to frame the image and touching the capture icon induces tremors and shakes that prevent the camera from capturing a steady picture.

To counter the lack of stabilization when capturing images on a hand-held gadget, manufacturers are incorporating mobiles with motion-sensors. These detect the tiniest of hand movements and cancel out the effects by making suitable corrections to the camera. Most motion-sensor devices are MEMS or Micro-Electro-Mechanical Systems based solid-state devices.

A global semiconductor leader, STMicroelectronics is a manufacturer and supplier of MEMS devices for consumer and mobile applications. ST is now offering the most advanced six-axis motion-sensing MEMS device that fully supports image stabilization for smartphones, tablets and Digital Still Cameras.

The iNEMOTH is the new range of inertial motion sensors from ST and includes the 6-axis motion-sensing IC, the LSM5D53H, which combines a 3-axis gyroscope and a 3-axis accelerometer. LSM5D53H is a System-in-Package solution offering its users the smallest package size with an ultra-low-power processing circuit that makes it the industry’s lowest power consuming IC.

LSM5D53H uses two techniques for minimizing image blurring that usually happens because of camera motion while capturing a snapshot. The first technique is the EIS or Electronic Image Stabilization, while the other is the OIS or Optical Image Stabilization. Although these techniques were initially meant for use on professional cameras, they are increasingly being deployed in tablets and smartphones. They are helpful in reducing image blurring that is likely to occur when the user is taking a snapshot with an outstretched arm.

ST has the necessary expertise and designs high-end gyroscopes for OIS. The company also plays a pioneering role in providing dual-core gyroscopes. These are capable of handling user motion and gesture recognition simultaneously while providing camera image stabilization. The LSM5D53H builds on this expertise.

Within the LSM5D53H is a tiny, ultra-low-power MEMS module. The IC allows equipment manufacturers to minimize the size, cost, system complexity and extending battery life for mobile devices with imaging applications. While systems employing two single-function gyroscopes consume 5mA, LSM5D53H does the same work while consuming less than 1mA and 1.1mA in its high-performance mode.

Offering an optimal motion experience and always-on low-power features for the consumer, the LSM5D53H system-in-package offers a 3D digital accelerometer and a 3D digital gyroscope performing up to 1.6 KHz ODR. Manufacturers can connect the device to the camera module via a dedicated auxiliary SP interface, while the primary interface is available via I2C or SPI.

ST manufactures the various sensing elements using their specialized micro-machining processes. They develop the IC interfaces using CMOS technology as this allows them to design a dedicated circuitry. The ST manufacturing process then trims the circuitry to match the characteristics of the sensing element in the best possible manner. The acceleration range of the LSM5D53H is +/- 16 g, while it has an angular rate ranging +/- 2000 dps.

What is Micro-porous Copper Foam Technology?

Apart from Aluminum, Copper is the most widely used material for making heat sinks, because properties of copper make it suitable for the purpose. Chief among them is its superior thermal conductivity and malleability. That means copper conducts heat better than most other materials and it is easy to form into different shapes that a heat sink necessitates. However, latest research has revealed another form of copper that promises still better thermal conductivities.

In today’s high-density electronics, thermal management plays a significant role. Reducing heat generation and removing heat from tight spaces is a constant challenge for electronics engineers designing smartphones, laptops, tablets and other space-constrained gadgets.

Engineers manage the heat generated in such high-density electronic designs by deploying optimized heat sinks. Versarien, a materials specialist, has found that using a micro-porous structure of copper maximizes its surface area enabling the heat sink become more effective in dissipating heat.

Micro-porous copper or copper foam has pores that vary in size from 300 to 600µm. The pores also make it lighter than solid copper, with a relative density of around 37%. Most importantly, the pores increase the surface area much more than that in traditional copper foam. A lost carbonate sintering process is responsible for generating the micro-pores.

Metallurgists compact and sinter a mixture of pure copper powder with a carbonate powder. This makes a matrix of copper ligaments, with the carbonate powder sandwiched in between. Once the mixture cools, water dissolves the carbonate, which is then recovered for recycling. The remaining copper forms a regular and uniform structure, which is highly rigid, porous and permeable and whose density per unit volume the manufacturer can easily control.

At present, Versarien makes heat sinks in form factors ranging from 10x10x2 to 40x40x5 mm. The company anticipates micro-porous copper foam heat sink usage in VOIP equipment, broadband routers, cable modems, flat panel displays, set top boxes and Gigabyte Passive Optical Network communication infrastructure.

Micro-porous copper foam is like an open cell structure, with an extraordinarily large number of interconnected pores distributed uniformly throughout the base copper material. To enhance its radiant properties, the manufacturer deposits a thin but exceedingly hard copper oxide coating at a high temperature. That gives the copper its high emissivity so desirable in a heat sink. Overall, you can have a significant height reduction in a passive heat sink footprint, without any compromise on its capacity to remove heat.

Testing provides evidence of its superior efficiency in heat removal. Micro-porous copper foam heat sinks outperform traditional solutions by more than 6°C/W. That means for every Watt of heat removed by a micro-porous copper foam heat sink, there is an additional temperature drop of about 6°C above what is offered by traditional heat sinks. For example, the thermal resistance of a 40x40x5 mm micro-porous copper foam heat sink is 17.4°C/W for an applied load of 5W. For a 20x20x5 mm heat sink, the thermal resistance is 35.8°C/W for an applied load of 2W.

Conventional heat sinks require special appendages such as pins, fins or micro-channels to increase their surface area. That increases the space taken up by the heat sink and makes it less efficient. When available space is limited, it is more practicable to use micro-porous copper foam heat sinks.