Dual-axis sun tracker sensor based on tetrahedron geometry Yuwaldi Away a , M. Ikhsan b, ⁎ a Graduate Program of Electrical and Computer Engineering, Syiah Kuala University, Indonesia b Electrical Engineering Education, Ar-Raniry State Islamic University, Indonesia abstract article info Article history: Received 3 July 2016 Received in revised form 19 September 2016 Accepted 27 October 2016 Available online xxxx This paper describes a new concept for solar detection sensor implementation in photovoltaic dual-axis sun tracker systems. The sensor uses only three units of identical light-dependent-resistors arranged in a tetrahedron and is able to track the source position of the sun or the strongest intensity of visible light. The prototype has been built and tested, resulting in a wide Field of View (289.4°) and minimum error. When this design is compared to other previous types of sun tracking sensors, it has great advantages in terms of sensor quantity, accuracy, effec- tiveness, and Field of View. © 2016 Elsevier B.V. All rights reserved. Keywords: Tetrahedron Pyramid shape Sun tracker LDR Dual-axis Photovoltaic 1. Introduction The increase in world energy demand and the strong intervention goals of the Kyoto protocol [1,2] have made renewable energy sources one of the best options in the world. It has been found that renewable energy has the fastest growing rate compared to other sources of energy [3]. Solar energy is a renewable energy that is also the major source of energy for other life forms on earth. This energy's abundance makes it highly desirable to exploit. However, due to the current limitations of human technology, only a fraction of the energy can be extracted. In solar panel applications, the highest theoretical effi- ciency is approximately 55% [4] although it can be considerably lower in practice. In general, there are two methods that maximize electrical energy output from solar panels: electrical and mechanical methods. The elec- trical methods are usually applied to control the power converter such that the energy output from the solar panel becomes maximal; the most common practice is the usage of Maximum Power Point Tracking (MPPT) systems. The mechanical method is also commonly used, where solar panels are periodically adjusted to remain perpendicular to the light source. Thus, the energy input received by the solar panels will increase. This method is known as a sun tracker system or a solar tracker. These two methods can be performed simultaneously [5] or separately. However, this paper only focuses on the second method, which is a sun tracker system. This paper presents a new concept for a light sensor, which can be applied to the sun tracker system. By integrating three light-depen- dent-resistors (LDR) in a tetrahedral arrangement, the device can be used as a dual-axis sun tracker sensor, which has an optimal control al- gorithm. The first section of the paper reviews prior research on the de- velopment of sun-tracker sensors. The next section presents the explanation of the proposed sensor in terms of structure and algorithm. Sensor testing, comparison, and a discussion are presented at the end of the paper. 2. Trend of sun tracker sensor A sun tracker is a device used to maximize the energy received by solar panels by maintaining its position perpendicular to the light source. It has been demonstrated both mathematically and experimentally that a sun tracker can increase the amount of energy received by solar panels by up to 60% [6,7,8], depending on the installation location. For example, Fig. 1 is the comparison result between the amounts of energy received by two solar panel systems at Banda Aceh, Indonesia. Both systems have the same electrical equipment, but they differ in mounting system. It was found that the system implementing a sun tracker can extract 54% more energy than the fixed mounting system (tracker energy consumption not included). Various sun tracker systems have been developed by many re- searchers, either using a special algorithms or different types of sensors. Automation in Construction xxx (2016) xxx–xxx ⁎ Corresponding author. E-mail addresses: yuwaldi@unsyiah.ac.id (Y. Away), m.ikhsan@ar-raniry.ac.id (M. Ikhsan). AUTCON-02166; No of Pages 9 http://dx.doi.org/10.1016/j.autcon.2016.10.009 0926-5805/© 2016 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Automation in Construction journal homepage: www.elsevier.com/locate/autcon Please cite this article as: Y. Away, M. Ikhsan, Dual-axis sun tracker sensor based on tetrahedron geometry, Automation in Construction (2016), http://dx.doi.org/10.1016/j.autcon.2016.10.009