Monthly Archives: October 2017

Raspberry Pi Helps a Hexapod Robot Walk

Roland Pelayo has used the single board computer, the famous Raspberry Pi or RBPi to help a hexapod robot learn to walk. The RBPi allows the robot to run in an autonomous mode, so it walks without assistance, avoiding obstacles. Alternately, it can also operate in a manual mode, whereby a user with a smartphone can control the robot. Most interestingly, the hexapod walker follows the tripod gait, just as most six-legged insects do.

Roland prefers to use servomotors to control the gait of the hexapod robot. According to Roland, using three servomotors to control the movement of the six legs of the robot, strikes a balance between performance and price. He added another servomotor for moving the eyes of the robot.

The servomotors allow the robot to move in four directions, forward, backward, left turn, and right turn. The robot moves by tilting itself to the left or the right, and then moving the leg lifted by its tilt. Roland has drawn diagrams explaining the movements of the robot. The backward and turn right movement of the robot is basically the reverse of its forward and turn right movement respectively.

Therefore, the front and corresponding back legs of the robot are interconnected to two servomotors, one to the left pair and the other to the right. The third servomotor helps to tilt the robot.

The RBPi allows the hexapod walker to operate in two modes. The first is the autonomous mode, which allows the robot to roam around freely, avoiding obstacles in its path. For instance, if it detects an obstacle in front, the robot walker takes two steps backwards, turns right, and then moves forward again. The second mode is for allowing the user control the movements of the hexapod robot using a smartphone on the same network as the robot is.

Roland has designed the program to allow the RBPi control four servos simultaneously, while reading inputs from a sensor detecting obstacles. The RBPi also connects to a network for the remote wireless control. Using an RBPi for the project was simpler for Roland, as the RBPi features on-board wireless connectivity.

Roland uses three Tower Pro SG-5010 servomotors, two for moving the legs and the third for tilting the hexapod walker. A fourth micro servo motor, a Tower Pro SG-90, helps to move the head and the eyes. An RBPi2 fitted with a USB Wi-Fi dongle helps to control the four servomotors. While the RBPi runs on a small power bank, the servomotors have their own separate power source. An ultrasonic sensor, HC-SR04, performs the obstacle detection.

As the echo produced by the ultrasonic sensor may cross the 3.3 V levels, Roland placed a voltage divider in between to connect to the RBPi, as its GPIO pins cannot accept voltages above 3.3 V.

As Python is already installed on the RBPi, Roland used it to write the program for the Hexapod walker. However, he also needed an extra library called pigpio, mainly for controlling the servomotors. He used SSH to access the RBPi remotely and installed the extra library.

Wash Your Solar Cells

To augment the energy supply, many are installing solar energy systems or residential solar panels. In general, these are flat units, placed at an angle on the rooftop. That naturally leads to the question of keeping them clean, which people equate to cleaning the roof itself. As this cleaning is usually left to the rainwaters, the next question comes as whether we should depend on the rains for cleaning the surface of the installed solar cells as well. Moreover, some also worry about whether water is good for the cells and will not damage them.

For these skeptics, scientists have a new type of waterproof solar cell that generates electricity even when compressed, stretched, or soaked in water. This is good news for those in the wearable solar cell industry. Wearable solar cells provide power to devices for monitoring health, usually as sensors incorporated into clothing, recording heartbeats, body temperature, and other parameters, for providing early warning of medical problems.

These extremely thin and flexible organic solar cells, or photovoltaic cells as scientists call them, are a result of research in the University of Tokyo. A material, by name PNTz4T, coats both sides of the cells with a stretchable and waterproof film. The researchers then deposit the cells within an inverse architecture of a one-micrometer-thick parylene film. After this process, the researchers applied an acrylic-based elastomer coating to both sides of the cell, which prevents water infiltration.

The elastomer is transparent and allows light to enter the cell, but does not allow air and water from leaking into it. This makes the solar cells longer lasting compared to conventional photovoltaic cells. The researchers decided to test the effectiveness of the coating by immersing the coated cells in water for two hours. They found the cells’ resistance to water to be high, as its efficiency to convert from light to electricity dropped by only 5.4 percent.

Next, the researchers tested the durability of the coated cell by subjecting it to compression. They compressed the cell by half for twenty cycles while placing drops of water on it. Even after surviving this brutal test, the researchers found the cell still had more than 80% of its original efficiency still intact. The above tests confirmed the cells’ mechanical robustness, high efficiency, and great environmental stability.

Not only as wearable sensors, these new washable, stretchable, and lightweight organic photovoltaic cells will also be suitable as long-term power sources as rooftop solar panels. Most experts do not recommend washing solar cells regularly for keeping the dust and debris from collecting on the surface. Since these new solar panels have the additional feature of being waterproof, there is no danger from giving them a frequent wash.

Experts feel it is best to let the rain take care of washing the solar panel. By monitoring the system functionality such as checking the energy bills and usage on monthly basis, the user can detect changes in the electricity bill. Another check can be made by visually inspecting the surface of the panels. If cleaning is necessary, washing it with a hose of water will do the job.

What is Optane Memory?

Optane is a revolutionary class of memory from Intel creating a bridge between dynamic RAM and storage for delivering an intelligent and amazingly responsive computing experience. For instance, Intel claims an increase of 28% in overall system performance, 14 times faster hard drive access, and two times increase in responsiveness in everyday tasks.

However, this revolution is not for everyone. It works only on the 7th generation Intel Core processor based systems that affordably maintain their capacity in mega-storage. For those using the above processor-based system, Intel promises Optane will deliver shorter boot times, faster application launching, extraordinarily fast gaming experience, and responsive browsing. However, there is a farther catch; you need to be running the latest Windows 10 operating system to take full advantage of Optane.

According to Intel, Windows 10 users on the 7th gen Intel Core processing systems can expect their computers to boot up twice as fast as earlier, with web browsers launching five times faster, and games launching up to 67% faster. Intel claims their Optane memory to be an adaptable system accelerator adjusting the tasks of the computer on which it is installed to run them more easily, smoothly, and faster. Intel provides an intelligent software for automatically learning the computing behavior and thereby accelerating frequent tasks and customizing the computer experience.

Intel’s new system acceleration solution places the new memory media module between the controller and other SATA-based storage devices that are slower. This includes SSHD, HDD, or SATA SSD. Based on 3D XPoint memory media, the module format stores commonly used programs and data close to the processor. This allows the processor to access information more quickly and thereby, improves the responsiveness of the overall system.

However, the Intel Optane memory module is not a replacement for the system Dynamic RAM. For instance, if a game requires X GB of DRAM, it cannot be divided between DRAM and Optane memory to meet the game requirements. Regular PC functioning will continue to require the necessary amount of DRAM.

For those who already have installed a solid-state disk or SSD in their computer systems can also install the Intel Optane memory for additional speed benefits. As such, the Intel Optane memory can extend acceleration to any type of SATA SSDs. However, the performance benefits are observed to be greater when the Intel Optane memory is used on slower magnetic HDDs, rather than when installed in systems with faster SSD-SATA.

Although other caching solutions exist, such as those using NAND technology, Intel’s Optane memory is entirely different. This new technology is a high performance, high endurance solution with low latency and quality of service or QoS. Optane uses the revolutionary new 3D XPoint memory media that performs well not only in low capacities, but also has the necessary endurance for withstanding multiple reading and writing cycles to the module.

In addition, Intel’s new Rapid Storage Technology driver, with its leading-edge algorithm, creates a compelling high-performance solution for a user-friendly, intuitive installation with easy to use setup process that automates the configuration to match the needs of the user.

Why do you need a Good Grounding?

Grounding is a safety measure for electrical and electronic systems whereby the user is protected from accidentally coming in contact with electrical hazards. For instance, refrigerators at home usually stand on rubber feet, even when operating from the AC outlet. Although electricity enters the refrigerator and runs through most of the electrical components within it, it has no connection to the outer metal body. Rather, the outer metal body of the refrigerator connects independently to a green grounding wire, which leads to the third pin (the thickest one) on the power plug.

If the outer metal body of the refrigerator was not grounded as above, and for some reason, electricity came in contact with the outer metal chassis such as from leakage, it would cause injury to anyone, if the person were to touch the refrigerator. Connecting the outer metal body to the grounding wire protects the person from being electrocuted, as electricity present on the metal body passes to the earth directly instead of through the person.

This is presuming the third pin on the power plug is connected to a good grounding arrangement outside the building. Typically, this arrangement is a ground rod, or a grounding electrode inserted into the soil. The arrangement works because the earth is a good conductor of electricity, and the overhead transformer that supplies power to the area, also has a grounding arrangement near it, which completes the circuit for the leakage current of the refrigerator. Therefore, a good grounding arrangement is essential for safety.

Apart from safety, most of the electronic equipment, such as computers, microwave ovens, LED lights, televisions, and more, need to be securely grounded to operate effectively. This is because most electronic equipment generate huge amounts of electrical noise that affect other equipment nearby. This can cause damage to an equipment, or cause it to work less effectively. Proper grounding helps to remove the unwanted noise, allowing all equipment to inter-operate more effectively.

Another advantage of a good grounding system is it helps protect against lightning. Lightning has high-voltage electricity with fast rise-times and causes large magnitude currents. A grounding system must present a low-resistance path for the high currents from a lightning strike to enter the earth, without causing damage to the building or equipment within.

Therefore, low resistance or low impedance of grounding is the key to protection from leakage of electricity, electrical noise, and lightning strikes. A good practice is to have all grounding connections as short and direct as possible, and connected with a heavy gauge wire, preferably made of copper. This ensures minimization of inductance and reduces the peak voltages induced.

The effectiveness of the grounding system in coupling the unwanted electricity to ground depends on a number of factors. This primarily includes the geometry of the ground electrode, the size of the conductors, the effective coupling into the soil, and the resistivity of the soil around the electrode.

Therefore, the basic requirements of any ground installation are to maximize the surface area of the electrode with the surrounding soil. This helps to lower the earth resistance and impedance.