A Low-Cost Automatic Free Space Optical Link Alignment System

In this paper, we present a prototype of a low-cost short-distance Free-space Optical link auto-alignment system using Arduino Uno R3 and a stepper motor controlled using a precise controller. The proposed alignment system uses a low- cost wireless transceiver with a 2.4 GHz antenna, enabling it to communicate over 100m in free space. A 500mW 520 nm green laser and a 1.5V solar photo-voltaic module have been used in the system for transmitting and receiving data, respectively, for demonstration purposes. The prototype is tested up to a distance of 78 meters with a clear line-of-sight and beam spreading is measured up to a distance of 48 meters. The prototype may find applications in setting up optical links for shorter distances where laying and maintaining optical fibers may be challenging and costly. The methodology proposed can also be scaled up for longer distances using more sophisticated components.