Probing Liquids Using Miniaturized NIRS


Keywords: Liquid sensing, NIRS, Prototyping.

Near-Infrared Spectroscopy (NIRS) is a non-invasive sensing technique which can be used to acquire information on an object's chemical composition. Although NIRS is conventionally used in dedicated laboratories, the recent introduction of miniaturized NIRS scanners has greatly expanded the use cases of this technology. Previous work shows that miniaturized NIRS can be successfully adapted to identify medical pills and alcohol concentration. We further extend this technology to identify sugar (sucrose) contents in everyday drinks. We developed a standalone mobile device which includes inter alia a NIRS scanner and a 3D printed clamp. The clamp can be attached to a straw-like tube to sense a liquid's sucrose content. Through a series of studies, we show that our technique can accurately measure sucrose levels in both lab-made samples and commercially available drinks, as well as classify commercial drinks. Furthermore, we show that our method is robust to variations in the ambient temperature and lighting conditions, as well as other liquids including milk, perfume and alcohols. Our method contributes to the development of everyday "food scanners" consumers.

[pdf] [src]

Wi-Fi Backscattering Platform


Keywords: Wireless communication, Backscattering, Ultra low power, Prototyping.

We designed and implemented an ultra low power Wi-Fi backscattering development platform using the Texas Instrumental (TI) MSP432 solution. The development board includes GPIO ports for connecting data source devices such as sensors, microphones, and cameras. We also integrated an RF front-end using analog switches for data modulation and reflecting Wi-Fi signals. The size of the PCB board was similar to a credit card of 84 x 56 mm with 0.8 mm thickness, which can be further miniaturized using smaller parts. In addition, we also implemented a GNU Radio software for SDR hardwares for receiver-side development.

Wirelessly Powered Robotic Caterpillar


Keywords: Wireless power transfer, Soft robot, Prototyping.

Wireless power transfer (WPT) has the significant potential for soft-bodied continuum robots to extend the operational time limitlessly and reduce weight. However, rigid power receiver coils, widely used in WPT, hinder the continuum deformation of the robot, and as a result, the function realization using the continuum deformation (e.g., locomotion) is impaired. Therefore, we introduce that a soft-bodied continuum robot can be designed by using thin film receiver coils and an inductively coupled wireless powering solution without sacrificing the continuum deformation and locomotion ability. A system is described for powering and controlling a soft robotic caterpillar consisting of nothing more than its continuum structure, actuators, and thin/flexible power receiving coils.


Wirelessly Powered Smart Rings


Keywords: Wireless power, Smart ring, Wearable.

Smart ring is one of the emerging wearables. It provides magnitudes of higher efficiency for input tasks, such as text input and gesture recognition. However, most smart rings suffer from large size due to the need of batteries, which deteriorates their wearability.

In this study, we present a truly wearable wirelessly powered smart rings that is thin, lightweight, and can work freely without battery life concerns. For achieving this functionality, our system aims at delivering power from a wristband to the smart rings wirelessly, utilizing the magnetic resonant coupling technique.

Power Allocation for Asymmetric Wireless Sensor Networks


Keywords: Optimization, Information Theory, Wireless Communication, Algorithm, WSN.

In this study, we investigate the power allocation problem for an asymmetric wireless senor network, where multiple sensors observe a common binary source and transmit their corrupted observations to a data fusion node. We propose a power allocation scheme by maximizing the weighted channel capacity subject to the sum power constraint and show that this problem is convex. The simulation results verify that the proposed power allocation scheme outperforms the uniform power allocation method. Furthermore, a scheduling scheme for binary data gathering is proposed by determining the sensors that dominate the bit error rate performance.


Pulse: Magnetic Wireless Communication for Smartphones


Keywords: Wireless Communication, Prototyping, Smartphone.

We present Pulse, a wireless magnetic communication protocol for smartphones. Pulse is designed for off-the-shelf Android smartphones with magnetometers, and encodes data in magnetic fields. We present the design and evaluation of Pulse in various conditions (e.g., different voltages, number of transfer channels). The system provides security due to its short range (~1 cm), it can reach a speed of up to 44 bits per second, and it is possible to run it on most mobile phones with a magnetometer. We present our evaluation and discuss practical use cases where Pulse can be used today.

[pdf] [video] [src]

UAV Sensor Network


Keywords: UAV, Quadcopter, Control, Kalman filter, Web development (full-stack).

We present a collaboration system of ground based robot and UAVs forming a sensor network. The ground based robot can control multi UAVs with predefined scripts simultaneously. It can acquire environmental condition information (temperature, magnetism, and barometric pressure) and images from the UAVs and upload the data to a cloud server. A website is developed to provide interactive data visualization functions.

We also studied on Inertial Navigation System for the UAVs, the experimental results showed that the errors of Inertial Navigation System are very huge, thus future work for navigation and positioning is required by combining onboard vision.


Random codings

Some random codings.

An object tracking tool using PyQt and OpenCV.

A linux task manager based on PyQt4 and Qwt5.

A python filesystem emulator using iNode.

My customizable 2048 game using Vue.

Contributions to Google Maps

I somethings upload photos to Google Maps, here is the most popular one (more than 2 million views).


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