Charles D. Ramey

2nd Floor TSRB

85 5th St NW

Atlanta, GA 30308

Hello there! My name is Charles Ramey. I am a PhD student at the Georgia Institute of Technology studying Computer Science with an emphasis on Intelligent Systems. My research interests include pattern recognition, low-power embedded systems, capacitive sensing, robotics, wearable computing, animal computer interaction, and rapid prototyping.

In my free time I enjoy building combat robots, hifi speakers, playing guitar, and cooking.

Here you’ll find a blog page which is host to brief thoughts or short project updates. I also have a dedicated projects page which has information on some of my completed past projects.

If you have any questions please feel free to shoot me an email! Cheers!

selected publications

Duco: Autonomous Large-Scale Direct-Circuit-Writing (DCW) on Vertical Everyday Surfaces Using A Scalable Hanging Plotter

Cheng, Tingyu, Li, Bu, Zhang, Yang, Li, Yunzhi, Ramey, Charles , Jung, Eui Min, Cui, Yepu, Swaminathan, Sai Ganesh, Do, Youngwook, Tentzeris, Manos, Abowd, Gregory D., and Oh, HyunJoo

Proc. ACM Interact. Mob. Wearable Ubiquitous Technol. 2021

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Human environments are filled with large open spaces that are separated by structures like walls, facades, glass windows, etc. Most often, these structures are largely passive offering little to no interactivity. In this paper, we present Duco, a large-scale electronics fabrication robot that enables room-scale & building-scale circuitry to add interactivity to vertical everyday surfaces. Duco negates the need for any human intervention by leveraging a hanging robotic system that automatically sketches multi-layered circuity to enable novel large-scale interfaces. The key idea behind Duco is that it achieves single-layer or multi-layer circuit fabrication on 2D surfaces as well as 2D cutouts that can be assembled into 3D objects by loading various functional inks (e.g., conductive, dielectric, or cleaning) to the wall-hanging drawing robot, as well as employing an optional laser cutting head as a cutting tool. Our technical evaluation shows that Duco’s mechanical system works reliably on various surface materials with a wide range of roughness and surface morphologies. The system achieves superior mechanical tolerances (0.1mm XY axis resolution and 1mm smallest feature size). We demonstrate our system with five application examples, including an interactive piano, an IoT coffee maker controller, an FM energy-harvester printed on a large glass window, a human-scale touch sensor and a 3D interactive lamp.
MARS: Nano-Power Battery-Free Wireless Interfaces for Touch, Swipe and Speech Input

Arora, Nivedita, Mirzazadeh, Ali, Moon, Injoo, Ramey, Charles , Zhao, Yuhui, Rodriguez, Daniela C., Abowd, Gregory D., and Starner, Thad

In The 34th Annual ACM Symposium on User Interface Software and Technology 2021

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Augmenting everyday surfaces with interaction sensing capability that is maintenance-free, low-cost (∼ $1), and in an appropriate form factor is a challenge with current technologies. MARS (Multi-channel Ambiently-powered Realtime Sensing) enables battery-free sensing and wireless communication of touch, swipe, and speech interactions by combining a nanowatt programmable oscillator with frequency-shifted analog backscatter communication. A zero-threshold voltage field-effect transistor (FET) is used to create an oscillator with a low startup voltage (∼ 500 mV) and current (< 2uA), whose frequency can be affected through changes in inductance or capacitance from the user interactions. Multiple MARS systems can operate in the same environment by tuning each oscillator circuit to a different frequency range. The nanowatt power budget allows the system to be powered directly through ambient energy sources like photodiodes or thermoelectric generators. We differentiate MARS from previous systems based on power requirements, cost, and part count and explore different interaction and activity sensing scenarios suitable for indoor environments.
Ice Topography Reconstruction and Panoramic Stitching using Forward Looking Sonar Images

Spears, Anthony, Meister, Matthew, Ramey, Charles , Lawrence, Justin, Dichek, Daniel, Washam, Peter, and Schmidt, Britney E.

In Global Oceans 2020: Singapore – U.S. Gulf Coast 2020
Wear-a-CUDA: a GPU based dolphin whistle recognizer for underwater wearable computers

Ramey, Charles , Gilliliand, Scott, Kolhsdorf, Daniel, and Starner, Thad

In Proceedings of the 2018 ACM International Symposium on Wearable Computers 2018

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Modular Controls and Instrumentation Software for Icefin ROV

Ramey, Charles , Meister, Matthew, Spears, Anthony, Lutz, Josh, Dichek, Daniel, Hurwitz, Ben, Lawrence, Justin, Lawrence, Jade, Philleo, Margaret, and Schmidt, Britney E

In OCEANS 2018 MTS/IEEE Charleston 2018

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Icefin: Redesign and 2017 Antarctic Field Deployment

Meister, Matthew, Dichek, Daniel, Spears, Anthony, Hurwitz, Ben, Ramey, Charles , Lawrence, Justin, Philleo, Kit, Lutz, Josh, Lawrence, Jade, and Schmidt, Britney E

In OCEANS 2018 MTS/IEEE Charleston 2018

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