Jenga—that game that needs careful use of agile and deft fingers, as well as careful consideration of which block can be removed without toppling the tower. Yup, that game! A robot can play that game.
Engineers at the Massachusetts Institute of Technology developed a self-learning robot with a soft-pronged gripper, a force-sensing wrist cuff, and an external camera, which it uses to see and feel the structure of the Jenga tower and its individual blocks. The details of the Jenga-playing smart machine were published in the journal Science Robotics.
The machine-learning approach of the Jenga-playing robot could help robots in assembling small parts in a manufacturing line like mobile phones
The Jenga-playing Robot
With the information it receives from its camera, the robot can analyze and compare this information to the moves it has previously made. It considers the outcomes of those moves to make a calculation about which individual piece could be moved and how much force is needed to be used to remove the piece successfully. The robot “learns” in real-time about the best moves for different situations in the game.
Alberto Rodriguez, assistant professor in the Department of Mechanical Engineering at MIT, said the Jenga-playing smart machine achieved something that cannot be done by previous smart systems:
“Unlike in more purely cognitive tasks or games such as chess or Go, playing the game of Jenga also requires mastery of physical skills such as probing, pushing, pulling, placing, and aligning pieces. It requires interactive perception and manipulation, where you have to go and touch the tower to learn how and when to move blocks. This is very difficult to simulate, so the robot has to learn in the real world, by interacting with the real Jenga tower. The key challenge is to learn from a relatively small number of experiments by exploiting common sense about objects and physics.”
How the Jenga-playing Robot learned to Play
For a robot to learn how to play Jenga, it would need at least tens of thousands of block-extraction attempts as initial data. The self-learning robot, however only needed about 300. The researchers used a more data-efficient way to let the robot to learn how to play Jenga. It is inspired by human cognition, the way we ourselves learn and approach the game.
The team used a customized industry-standard ABB IRB 120 robotic arm. It was first trained with 300 random extraction attempts on the Jenga tower. With each attempt, a computer would record the associated visual and force measurements of the move and mark each of them with a success or failure.
It clusters one attempt with many similar measurements and outcomes to represent one behavior to increase efficiency. This is the same way in which humans cluster similar behavior.
“The robot builds clusters and then learns models for each of these clusters, instead of learning a model that captures absolutely everything that could happen,” said Nima Fazeli, MIT graduate student and lead author of the paper.
Beyond Playing Jenga
This robot is not just a playing companion for those who cannot find someone to play Jenga with. The researchers highlighted that its ability to quickly learn the best way to carry out a task, not just from visual cues but from real situations, could be applied to creating robots that can do tasks that need careful physical interaction.
“In a cellphone assembly line, in almost every single step, the feeling of a snap-fit, or a threaded screw, is coming from force and touch rather than vision,” Rodriguez said. “Learning models for those actions is prime real-estate for this kind of technology.”
The day when mobile phones, laptops, and other gadgets won’t need their batteries anymore is near. Scientists created a new technology that could convert WiFi signals to electricity that could power electronics.
The new device called ‘rectenna’ could tap into nearby WiFi signals or other AC electromagnetic waves and supply power to electronics in a large area. Additionally, it is made from flexible and inexpensive materials which can easily be fabricated.
The Science Behind the ‘Rectenna’
In a paper published in the journal Nature, researchers at the Massachusetts Institute of Technology described how the rectennas work. It uses a flexible radio-frequency (RF) antenna which captures electromagnetic waves, including WiFi signals.
So where did the “rec-“ came from? To convert AC signal to electricity, the rectenna relies on a component known as a “rectifier,” which are typically made of either silicon or gallium arsenide. However, they are not flexible. And although they are not too expensive, they are inefficient in large areas.
The researchers created a novel two-dimensional semiconductor device made from molybdenum disulfide (MoS2). The device is just about three atoms thick, making it one of the world’s thinnest semiconductors.
“By engineering MoS2 into a 2-D semiconducting-metallic phase junction, we built an atomically thin, ultrafast Schottky diode that simultaneously minimizes the series resistance and parasitic capacitance,” said Xu Zhang, first author of the study. Parasitic capacitance is the condition in which certain materials store some electrical charge in electronics, slowing down the circuit. This is very common in all electronic devices
The antenna is connected to the semiconductor. As the AC signal travels to in it, it is converted into DC electricity which could be used to provide power to electronic circuits or recharge batteries. This way the rectenna could passively gather and transform the omnipresent Wi-Fi signals into much useful DC power.
Powering the ‘Electronic Systems of the Future’
After several experiments, the researchers found that when the device is exposed to Wi-Fi signals with typical power levels, which is around 150 microwatts, it can produce about 40 microwatts of power. This is enough to support a simple mobile display or silicon chips.
The innovation would be useful in supplying power to flexible and miniature electronics and wearables, which are too small for bulky and weighty batteries. It can also be used to certain medical devices, such as those which are implanted inside the body like a pacemaker. If these implantable medical devices leak lithium inside the body, it would be a great danger to patients.
The researchers also highlighted that the rectenna can be useful to future technological advances. Tomás Palacios co-author of the study and director of the MIT/MTL Center for Graphene Devices and 2D Systems in the Microsystems Technology Laboratories explained:
“What if we could develop electronic systems that we wrap around a bridge or cover an entire highway, or the walls of our office and bring electronic intelligence to everything around us? How do you provide energy for those electronics? We have come up with a new way to power the electronics systems of the future — by harvesting Wi-Fi energy in a way that’s easily integrated into large areas — to bring intelligence to every object around us.”
One of the problems of many parents nowadays is their children’s screen time. Persuading kids to take time off from their gadgets often does not end nicely. But here’s another reason to limit your children’s screen time—it is linked to their future development.
In a paper published in the journal JAMA Pediatrics, researchers found that toddlers 2-3 years old who spend a lot of time staring at screens have poorer performance on their developmental screening tests at 3-5 years old.
Critical Stage of Development
The development of children unfolds rapidly in the first 5 years of life, which is a critical period of growth and maturation. The researchers highlighted that too much screen time can negatively affect children’s natural development ability. This can also affect their readiness for school entry.
By spending too much time on screens, children might miss important opportunities to practice their motor, communication, and interpersonal skills. The researchers explained:
“For example, when children are observing screens without an interactive or physical component, they are more sedentary and, therefore, not practicing gross motor skills, such as walking and running, which in turn may delay development in this area. Screens can also disrupt interactions with caregivers by limiting opportunities for verbal and nonverbal social exchanges, which are essential for fostering optimal growth and development.”
Screen Time and Child Development
The researchers gathered data from 2,441 mothers and children in Canada. The mothers were given questionnaires on how much time children spent using electronics on a typical weekday and weekend. They were also asked questions related to the child’s performance on developmental tests at ages 24, 36 and 60 months. The developmental test can assess children’s growth in motor skills, problem-solving and communication, personal social skills.
Results revealed that longer screen time at 24 months was linked to poorer performance on developmental screening tests at 36 months. On the other hand, longer screen time at 36 months was linked with lower scores on developmental screening tests at 60 months.
“Excessive screen time can impinge on children’s ability to develop optimally; it is recommended that pediatricians and health care practitioners guide parents on appropriate amounts of screen exposure and discuss potential consequences of excessive screen use,” the researchers wrote.
Recommended Screen Time Limit
“On average, the children in our study were viewing screens two to three hours per day. This means that the majority of the children in our sample are exceeding the pediatric guidelines of no more than one hour of high-quality programming per day,” said Sheri Madigan, first author of the study from the University of Calgary.
According to the American Academy of Pediatrics, the recommended limit of screen time in children 2-5 years old is just one hour a day. Sheri likened screen time to junk food, “In small doses, it’s OK, but in excess, it has consequences.”
This screen time includes watching television programs, movies, videos, or stories on a VCR or DVD player. As well as using a computer, gaming system, mobile phone, laptop or other screen-based devices.
Wearable tech is a very popular trend. There are those which can monitor heart rate, blood pressure, and other health biosensors. There are also those which can monitor physical activity and calorie intake to help you stay fit. These gadgets are designed to be smaller; however, they require a lot of energy and thus, a larger battery.
Now, wearable tech is taking another leap with this new scientific invention—a fabric that could harness energy from body heat.
To tackle this problem of “heavy and bulky” power sources, researchers at the University of Massachusetts Amherst took advantage of the so-called “thermoelectric” effect. This theory explains how body heat can produce energy by moving electrical charge from a warm region toward a cooler one.
Previously, there were also some studies which investigated the idea to create energy-harnessing fabrics. However, the results were not safe and cost-effective. They either need very expensive, toxic materials or inefficient, harvesting only small amounts of power even after an eight-hour workday.
In a paper published in the online edition of Advanced Materials Technologies, researchers created and tested knitted bands of thermoelectric fabric. When worn on the hand, this material could generate thermo-voltages more than 20 milliVolts.
Wool and Cotton
The thermoelectric fabric was made of very inexpensive and abundant materials—wool and cotton. Not only they are flexible and lightweight, but the researchers also revealed they used wool and cotton to take advantage of their naturally low heat transport properties.
They explained that this is to maintain the “thermopile,” or the temperature gradient across an electronic device. This will make sure the material can convert heat to electrical energy even after “long periods of continuous wear,” making it “mechanically and thermally stable.”
“Essentially, we capitalized on the basic insulating property of fabrics to solve a long-standing problem in the device community. We believe this work will be interesting to device engineers who seek to explore new energy sources for wearable electronics and designers interested in creating smart garments,” the researchers wrote.
Assessing Durability and Conductivity
Digging deeper, the all-fabric thermopile was made by “vapor-printing” a polymer known as persistently p-doped poly(3,4-ethylenedioxythiophene) (PEDOT-Cl). They then integrated this weaves of fabric into a wearable band specially designed to generate thermo-voltages of more than 20 milliVolts.
To test its durability, the researchers soaked and rubbed the finished material in warm water and assessed their performance through electron micrograph scans. The result revealed that the material “did not crack, delaminate or mechanically wash away upon being laundered or abraded, confirming the mechanical ruggedness of the vapor-printed PEDOT-CI.”
They also tested its electrical conductivity using a custom-built probe on volunteers. They found that those with looser weave have higher conductivity. Additionally, the conductivity does not change even after rubbing and laundering
The researchers also highlighted that the wrist, palm, and upper arms are the most efficient areas to wear the fabrics as these areas produce most heat. The thermovoltage output of the material is also increased by perspiration. The researchers noted this is not surprising as cotton conducts heat better when damp.