ITcon Vol. 24, pg. 1-13, http://www.itcon.org/2019/1

Rapid Internet of Things (IoT) prototype for accurate people counting towards energy efficient buildings

submitted:March 2018
revised:December 2018
published:February 2019
editor(s):Amor R.
authors:Qian Huang, Assistant Professor
School of Architecture, Southern Illinois University Carbondale, IL, USA;
qhuang@siu.edu

Kane Rodriguez, Undergraduate Student
Department of Electrical and Computer Engineering, Southern Illinois University Carbondale, IL, USA;
kaustez@siu.edu

Nicholas Whetstone, Undergraduate Student
Department of Electrical and Computer Engineering, Southern Illinois University Carbondale, IL, USA; nickwhestone@siu.edu

Steven Habel, Undergraduate Student
Department of Electrical and Computer Engineering, Southern Illinois University Carbondale, IL, USA;
habels@siu.edu
summary:According to the U.S. Department of Energy, a significant portion of energy used in buildings is wasted. If the occupancy quantity in a pre-determined thermal zone is aware, a building automation system (BAS) is able to intelligently adjust the building operation to provide “just-enough” heating, cooling, and ventilation capacities to building users. Therefore, an occupancy counting device that can be widely deployed at low prices with low failure rate, small form-factor, good usability, and conserved user privacy is highly desirable. Existing occupancy detection or recognition sensors (e.g., passive infrared, camera, acoustic, RFID, CO2) cannot meet all these above system requirements. In this work, we present an IoT (Internet of Things) prototype that collects room occupancy information to assist in the operation of energy-efficient buildings. The proposed IoT prototype consists of Lattice iCE40-HX1K stick FPGA boards and Raspberry Pi modules. Two pairs of our prototypes are installed at a door frame. When a person walks through this door frame, blocking of active infrared streams between both pairs of IoT prototypes is detected. The direction of human movement is obtained through comparing occurrence time instances of two obstructive events. Thus, the change in occupancy quantity of a thermal zone is calculated and updated. Besides, an open-source application user interface is developed to allow anonymous users or building automation systems to easily acquire room occupancy information. We carry out a three-month random test of human entry and exit of a thermal zone, and find that the occupancy counting accuracy is 97%. The proposed design is completely made of off-the-shelf electronic components and the estimated cost is less than $160. To investigate the impact on building energy savings, we conduct a building energy simulation using EnergyPlus and find the payback period is approximately 4 months. In summary, the proposed design is miniature, non-intrusive, ease of use, low failure rate, and cost-effective for smart buildings.
keywords:Smart Building, Occupancy Counting, Internet of Things (IoT), Active Infrared FPGA, Accuracy
full text: (PDF file, 1.029 MB)
citation:Huang Q, Rodriguez K, Whetstone N, Habel S (2019). Rapid Internet of Things (IoT) prototype for accurate people counting towards energy efficient buildings, ITcon Vol. 24, pg. 1-13, https://www.itcon.org/2019/1