ST: Smart systems, MEMS to transform energy harvesting

While MEMS may be known now for their decades-old applications in the automotive industry and, in the consumer space, as the gyroscopes and accelerometers under the bonnets of our smartphones, in actual fact, the devices are really only at the beginning stages of development.

According to Carmelo Papa, general manager at STMicroelectronics, in 10 years time the game is going to look very different indeed. He told TechEye that MEMS will evolve into smart systems, which will become the core, together, with microcontrollers. Smart systems down the line could theoretically be equipped with electromagnetic and photovoltaic pads which can detect and harvest energy on the spot – through direct or indirect sunlight, or ambient light. Energy could be stored through flexible batteries and the calculations could all be performed with micro sensors. What is missing for this to happen, Papa says, is the transmission of the energy.

“Even in some cases,” Papa told TechEye, “you can also transmit data through the wireline of the house at 220 volts.” Because we aren’t fully aware of the effects of wireless communications, Papa said, there should be a mix between wired and wireless communications too. “In the end you share, some through the wireline and the rest you do wirelessly,” he said. New infrastructure won’t be necessary as this kind of powerline technology will operate on a normal live wire.

“MEMS will be smart systems that use both wired and wireless communications,” Papa said. “In the end, these will open up the field for new applications that are unthinkable today.”

A technology STMicro is already developing is the mixture of plastics and electronics. In a couple of years, Papa says, you will have, on the same system, completely integrated silicon and plastic. “You can increase the complexity of the devices,” he said. “One will be plastic, one will be purely silicon, and another will be silicon and plastic together. This increases the flexibility and reduces cost.” It won’t happen immediately but over the next few years.

Disposable electronics are one area where plastic electronics can have an immediate effect, according to Papa, like in healthcare devices with sensors that can detect the presence of certain viruses, and then can throw away. “3D integration, plastic, and silicon together, will increase the flexibility of smart systems,” he said. “But this will take some years.”
An example Papa cites of a real-world application where MEMS could prove useful include in firefighting. By having the correct sensors on firefighters, once they are in a building that’s on fire, it would be easier to monitor and figure out the exact danger areas. Or in areas which are at risk of mudslides, the correct kind of sensors could help predict when and how badly the mudslide would be. Or there are applications in anti-theft. With the proliferation of photovoltaic panels in emerging countries, the panels are targeted for theft. “You put MEMS on it, if they lift, the acceleration movement is detected and the signal is sent to a monitoring centre,” he said. More trivially, all you’d need is one of the tiny devices on the back of a painting in a museum and as soon as it moves, security knows. Industrial piping would benefit by monitoring gas flow – all it would need is a differential pressure sensor to detect any problems.

Of course, these kinds of technologies – from MEMS available today right the way through to data harvesting – efficient low power designs are absolutely necessary. “You really need to master the low energy consumption devices,” Papa said. “Everything is connected, so you need parallel improvement in all technologies – with data harvesting you are looking at nano-amperes in some cases, therefore you really need to master the lower consumption power technologies.”