Una radio da un millimetro cubo contro il glaucoma

I ricercatori dell'Università del Michigan hanno messo a punto un sensore di pressione intra-oculare da utilizzare per il monitoraggio preventivo dell'insorgenza di glaucoma. Un sistema computerizzato che ha le dimensioni di una lettera "N" sulla moneta da un centesimo di dollaro! Il risvolto più interessante per noi è la presenza di un sofisticato sistema di trasmissione dati FSK "near-field", con una antenna realizzata con tecniche di incisioni CMOS che ha una dimensione complessiva di 1,2 x 1,6 millimetri e risuona nella banda dei 60 GHz consumando pochi nanoWatt (e non ha bisogno di cristallo di riferimento, essendo "auto-riferita"). La batteria che alimenta il sistema, programmato per rilevare la pressione ogni 15 minuti e accumulare fino a una settimana di misurazioni, che possono essere "scaricate" eccitando la radio di bordo dall'esterno. L'ingegnerizzazione di questa picolla meraviglia apre la strada a un mondo di applicazioni

basate su reti di sensori praticamente invisibili. Quello che segue è il testo del comunicato stampa di UniMichigan, ma tre dei responsabili del progetto, David Blaauw, David Wentzloff e Dennis Sylvester, hanno pubblicato un più dettagliato articolo sulla parte RF, "Shrinking radios for millimeter-scale computers". Lo trovate su EEtimes.

Toward computers that fit on a pen tip: New technologies usher in the millimeter-scale computing era

ANN ARBOR, Mich.---A prototype implantable eye pressure monitor for glaucoma patients is believed to contain the first complete millimeter-scale computing system.

And a compact radio that needs no tuning to find the right frequency could be a key enabler to organizing millimeter-scale systems into wireless sensor networks. These networks could one day track pollution, monitor structural integrity, perform surveillance, or make virtually any object smart and trackable.

Both developments at the University of Michigan are significant milestones in the march toward millimeter-scale computing, believed to be the next electronics frontier.

Researchers present papers on each today at the International Solid-State Circuits Conference (ISSCC) in San Francisco. The work is being led by three faculty members in the U-M Department of Electrical Engineering and Computer Science: professors Dennis Sylvester and David Blaauw, and assistant professor David Wentzloff.

Bell's Law and the promise of pervasive computing

Nearly invisible millimeter-scale systems could enable ubiquitous computing, and the researchers say that's the future of the industry. They point to Bell's Law, a corollary to Moore's Law. (Moore's says that the number of transistors on an integrated circuit doubles every two years, roughly doubling processing power.)

Bell's Law says there's a new class of smaller, cheaper computers about every decade. With each new class, the volume shrinks by two orders of magnitude and the number of systems per person increases. The law has held from 1960s' mainframes through the '80s' personal computers, the '90s' notebooks and the new millennium's smart phones. "When you get smaller than hand-held devices, you turn to these monitoring devices," Blaauw said. "The next big challenge is to achieve

millimeter-scale systems, which have a host of new applications for monitoring our bodies, our environment and our buildings. Because they're so small, you could manufacture hundreds of thousands on one wafer. There could be 10s to 100s of them per person and it's this per capita increase that fuels the semiconductor industry's growth."

The first complete millimeter-scale system

Blaauw and Sylvester's new system is targeted toward medical applications. The work they present at ISSCC focuses on a pressure monitor designed to be implanted in the eye to conveniently and continuously track the progress of glaucoma, a potentially blinding disease. (The device is expected to be commercially available several years from now.)

In a package that's just over 1 cubic millimeter, the system fits an ultra low-power microprocessor, a pressure sensor, memory, a thin-film battery, a solar cell and a wireless radio with an antenna that can transmit data to an external reader device that would be held near the eye. "This is the first true millimeter-scale complete computing system," Sylvester said. "Our work is unique in the sense that we're thinking about complete systems in which all the components are low-power and fit on the chip. We can collect data, store it and transmit it. The applications for

systems of this size are endless."

The processor in the eye pressure monitor is the third generation of the researchers' Phoenix chip, which uses a unique power gating architecture and an extreme sleep mode to achieve ultra-low power consumption. The newest system wakes every 15 minutes to take measurements and consumes an average of 5.3 nanowatts. To keep the battery charged, it requires exposure to 10 hours of indoor light each day or 1.5 hours of sunlight. It can store up to a week's worth of information. While this system is miniscule and complete, its radio doesn't equip it to talk to other devices like it. That's an important feature for any system targeted toward wireless sensor networks.

A unique compact radio to enable wireless sensor networks

Wentzloff and doctoral student Kuo-Ken Huang have taken a step toward enabling such node-to-node communication. They've developed a consolidated radio with an on-chip antenna that doesn't need the bulky external crystal that engineers rely on today when two isolated devices need to talk to each other. The crystal reference keeps time and selects a radio frequency band. Integrating the antenna and eliminating this crystal significantly shrinks the radio system. Wentzloff's is less than 1 cubic millimeter in size.

He and Huang's key innovation is to engineer the new antenna to keep time on its own and serve as its own reference. By integrating the antenna through an advanced CMOS process, they can precisely control its shape and size and therefore how it oscillates in response to electrical signals.

"Antennas have a natural resonant frequency for electrical signals that is defined by their geometry, much like a pure audio tone on a tuning fork," Wentzloff said. "By designing a circuit to monitor the signal on the antenna and measure how close it is to the antenna's natural resonance, we can lock the transmitted signal to the antenna's resonant frequency."

"This is the first integrated antenna that also serves as its own reference. The radio on our chip doesn't need external tuning. Once you deploy a network of these, they'll automatically align at the same frequency." The researchers are now working on lowering the radio's power consumption so that it's compatible with millimeter-scale batteries.

Greg Chen, a doctoral student in the Department of Electrical Engineering and Computer Science, presents "A Cubic-Millimeter Energy-Autonomous Wireless Intraocular Pressure Monitor." The researchers are collaborating with Ken Wise, the William Gould Dow Distinguished University Professor of Electrical Engineering and Computer Science on the packaging of the sensor, and with Paul Lichter, chair of the Department of Ophthalmology and Visual Sciences at the U-M Medical School, for the implantation studies. Huang presents "A 60GHz Antenna-Referenced Frequency-Locked Loop in 0.13μm CMOS for Wireless Sensor Networks." This research is funded by the National Science Foundation. The university is pursuing patent protection for the intellectual property, and is seeking commercialization partners to help bring the technology to market.

Telescopi neutrinici o microfoni per balene?

Straordinario questo esempio di multidisciplinarietà in una realtà scientifica che si fa sempre più complessa e specializzata, ma anche densa di vere e proprie connessioni neuronali tra le varie discipline. Generando un fascino a mio parere davvero "epico" all'altezza delle grandi narrative che hanno connotato nei secoli l'umanesimo, tenendolo paradossalmente lontano da una scienza "fredda" e senza cuore.

Nelle profondità del Mediterraneo gli "astrofisici particellari" dispongono i loro telescopi per indagare interazioni tra neutrini e materia, mutuate attraverso la luce di Cherenkov (progetto KM3NeT con un interessante documento sui "telescopi neutrinici"). Poi ci si accorge che le lunghezze d'onda in gioco sono le stesse che consentirebbero il monitoraggio delle attività dei cetacei in profondità e la rete di sensori dispiegata per osservare muoni e adroni viene adattata, con l'aggiunta di sensori bioacustici, per ascoltare le balene. Da qui nasce il sito di LIDO, Listening to the Deep Ocean environment, che offre la rara opportunità di entrare in contatto uditivo con la lenta variabilità degli abissi marini (dalla Sicilia sudorientale partecipa la torre del progetto NEMO).

Ecco il comunicato del CERN sul progetto CLOUD (uno studio tra la possibile interazione tra raggi cosmici e formazione delle nuvole) che mi ha rivelato tutte queste meraviglie.

Listening to whales with neutrino telescopes

Whales sing at the same wavelength as the neutrinos emitted by stars. This happy coincidence gave physicists the idea to share their undersea telescopes with marine biologists. By helping the development of a bioaccoustics network to monitor the deep sea environment, they have already enabled the discovery of the unexpected presence of sperm whales in the Mediterranean Sea. It is even possible to listen to the song of whales live from home with a personal computer connected to the web, thanks to the LIDO platform (Listen to the Deep Ocean) : http://listentothedeep.com/

European astroparticle physicists are developing together KM3NeT, a large undersea neutrino telescope in the Mediterranean, dedicated to tracking neutrinos from astronomical sources. The deployment of deep sea neutrino detection lines for current experiments such as Antarès in France, Nemo in Italy and Nestor in Greece has opened up the possibility of also installing monitoring devices for the permanent study of the deep sea environment: studies of ocean currents, of bioluminescence, of fauna and of seismic activity.

Astroparticle physics is a new field mixing both particle physics and astrophysics and offering many new opportunities for environmental disciplines such as oceanography, climate science and studies of the atmosphere, geology…

The ASPERA European network for astroparticle physics and CNRS/IN2P3 invite the media to participate in the workshop « From the Geosphere to the Cosmos » on 1st and 2nd December at the Palais de la Découverte in Paris, where the new synergies and challenges of environmental sciences and astroparticle physics will be presented.

Journalists are very welcome to attend the whole event. A press briefing will be held on the 1st December 16:15 at the Palais de la Découverte in Paris, where the following projects will be presented:

LIDO - for listening to the deep sea environment from home over the internet,

The CLOUD experiment at CERN, which studies the impact of cosmic rays on clouds and climate,

3D-radiography projects for volcanoes, using particle detectors

Probing new territories

Astroparticle physics is an excellent example of interdisciplinarity, combining the research and technologies of both particle physics and astrophysics. Over the last few years, new methods for observing the Universe have been devised. With astroparticle physics, it is no longer a question of simply studying the light that comes from the stars. Rather, the very particles emitted by cosmic bodies can be detected and analysed. Cosmic rays and neutrinos have a whole new story to tell about the violent processes underway in black holes and supernovae. Be it tracking dark matter particles in underground laboratories, or fishing for neutrinos in the ocean’s depths, today’s physicists can appear almost as characters from Jules Verne, modern-day explorers of the wonders of our Universe.

By deploying large infrastructures in unusual places, astroparticle physics offers new opportunities for other scientific disciplines for studying the atmosphere, the ocean, biology in extreme conditions…

Developing new technologies

Astroparticle physics also offers a perspective of extremely promising technologies to come. Just as it is possible to image the human body with X-rays, particle physics detectors should soon be able to make three dimensional images of volcanoes and thus help in better understanding their mechanisms and indeed risk prevention. As they interact very weakly with ordinary matter, some particles such as neutrinos and muons cross huge thicknesses of rock, revealing the densities of the different layers they go through. In addition, geoneutrinos could allow for studies of the Earth’s core.

Better understanding of the atmosphere and climate

Cosmic rays are charged particles that bombard the Earth's atmosphere from outer space. The deployment of large cosmic ray experiments such as the Pierre Auger Observatory in Argentina, or indeed satellite-based experiments, helps to continuously and precisely monitor the atmosphere on a large scale. Such experiments offer the possibility to study the role that cosmic rays could play in triggering lightning in thunderstorms. Moreover, studies suggest that cosmic rays might even have an influence on the amount of cloud cover through the formation of aerosols. CLOUD is an experiment at CERN in Geneva that uses a cloud chamber to study the possible link between cosmic rays and cloud formation. The results could greatly modify our understanding of clouds and climate.