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- Varshney, Ambuj
(författare)
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Position : Wearable Polymorphic Light Sensors
- 2019
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Ingår i: WEARSYS'19. - New York, NY, USA : Association for Computing Machinery (ACM). ; , s. 37-38
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Konferensbidrag (refereegranskat)abstract
- Light is an emerging medium to enable sensing for wearable devices. Sensing light enables new scenarios, such as controlling devices with gestures. However, a limitation of most existing systems is that they sense only a small part of the spectrum. In this position paper, we argue that the ability to detect a broad light spectrum significantly enhances light sensing systems. We introduce the concept of polymorphic light sensing~(PLS), which enables the tracking of different parts of the light spectrum (colours, infrared, and ultraviolet light). We design a backscatter enabled light sensor using the PLS mechanism and devise mechanisms to allow operation in diverse light conditions.
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| 2. |
- Varshney, Ambuj, et al.
(författare)
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TunnelScatter : Low Power Communication for Sensor Tags using Tunnel Diodes
- 2019
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Ingår i: MOBICOM'19. - New York, NY, USA : ACM.
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Konferensbidrag (refereegranskat)abstract
- Due to extremely low power consumption, backscatter has become the transmission mechanism of choice for battery-free devices that operate on harvested energy. However, a limitation of recent backscatter systems is that the communication range scales with the strength of the ambient carrier signal (ACS). This means that to achieve a long range, a backscatter tag needs to reflect a strong ACS, which in practice means that it needs to be close to an ACS emitter. We present TunnelScatter, a mechanism that overcomes this limitation. TunnelScatter uses a tunnel diode-based radio frequency oscillator to enable transmissions when there is no ACS, and the same oscillator as a reflection amplifier to support backscatter transmissions when the ACS is weak. Our results show that even without an ACS, TunnelScatter is able to transmit through several walls covering a distance of 18m while consuming a peak biasing power of 57 mu W. Based on TunnelScatter, we design battery-free sensor tags, called TunnelTags, that can sense physical phenomena and transmit them using the TunnelScatter mechanism.
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