The incorporation of Internet of Things (IoT) in agriculture promises to revolutionize farming, enhance productivity, and contribute to sustainable food production. This article introduces a novel IoT framework integrating optical camera communication (OCC) and radio frequency (RF) for advanced farming. OCC emerges as an efficient technology for wireless sensor networks, particularly where low power consumption, cost-effectiveness, and noncritical transmission rates are prioritized. Our innovative design effectively combines the strengths of both OCC and RF, setting the stage for cost-effective IoT solutions in farming. Validated through extensive experiments, this hybrid network demonstrates not only efficiency and flexibility but also its capability for rapid deployment across various conditions. The system uses unidirectional communications, where sensors periodically emit data without the need for polling or network access protocols, reducing the need for complex circuits and lowering power consumption. Remarkably, it achieved robust communication over 90 m with a 94% data recovery rate in diverse conditions, indicating a reliability of over 99.83%, supported by a theoretical BER of$1.7 \times 10^{-3}$. This approach offers agile, affordable monitoring and is farmer-friendly. Notably, the flexibility of the OCC/RF combination addresses diverse farming needs. Our findings highlight the system’s capacity to accurately gather environmental data, enhancing user experience. The subpixel OCC feature supports scalability across large areas like crop fields, meeting dynamic agricultural needs. Overall, the integration of OCC and RF, bolstered by subpixel technology, marks a significant advancement in agricultural IoT applications.

This paper presents an experimental study of water-to-air optical camera communication (OCC) in the presence of wavy surface conditions. It evaluates the system performance in terms of the signal-to-noise ratio (SNR), considering various camera exposure times and regions of interest (ROI) in captured images. The results reveal a noticeable reduction in the SNR due to the presence of surface waves. However, the system performance is improved by considering the average value of several illuminated pixels produced by the point spread function as the ROI. Furthermore, the statistical characteristics of the received optical signals in the presence of surface waves are assessed.

Visible Light Communications (VLC) allow new solutions and applications thanks to the advantages of optical wireless communications. It can be used on any mobile phone device, since these already bear the required hardware component (LED in the mobile screen), and as a result inmediate application is possible. The technological principle of VLC in controlled access is based on the use of the mobile LED (screen), which can transmit codes by modulating the LED light in the sub-second domain and offered in an App, and an optical receiver in the device to be accessed, which is able to decode and verify the codes sent. Given the universal integration of mobile devices in our society, LightKey project is an intuitive and multi-purpose solution for any user, and is able to ensure a secure and personal controlled access. For industrial applications LightKey can become a middleware between users and a host. This implies that LightKey will not store any personal data, but will communicate with the host, mainly by wireless communication, and the host will be responsible for validating the codes received.

This work presents Barcolits, active LED tags that exploit the sequential acquisition of rolling-shutter cameras to materialize virtual barcodes in images. The generated barcodes have valuable properties. Compared to physically printed bar-codes, its size (in pixels) does not change with the distance to the camera. Also, its stripes are always vertically aligned in the image independently of the rotation and position of the camera. Moreover, as Barcolits are active devices, they can be scanned under low light conditions or from reflections in walls or mirrors. Furthermore, this approach reuses conventional barcode detection and decoding algorithms, allowing interoperability and backwards compatibility with current barcode scanners (image or photodiode-based). These benefits have been experimentally validated using three different barcode encoding schemes: Code 128, EAN-13 and ITF. In the experiment conducted, these barcodes are compared in terms of their minimum required size to ensure high reliability, their data density, their signal level, and their likelihood to produce flickering in the LED source. The experiment results show that Code 128 are ideal for high throughput data sharing, with the highest achievable data density of 4.92 bits per pixel and the lowest power consumption. It outperforms standard manchester codes by encoding 42% more bits using the same payload size. On the other hand, EAN -13 barcodes require the smallest size for a successful scan but produce noticeable flickering if a long stream of different barcodes is transmitted. Finally, ITF codes mitigate flickering at the cost of reducing their density. This extensive analysis provides a comparison tool to help choose the optimal barcode scheme for different applications and environments.

Optical camera communication (OCC) is an innovative set of optical wireless communication that exploits the ever-increasing availability of cameras and solid-state lighting equipment to establish low data rate optical links. This paper evaluates the feasibility of implementing OCC links between sensor nodes in a field outdoors and a camera connected to the cloud in an emulated farming environment. The power efficiency and low maintenance constraints of wireless sensor networks (WSN) are considered in the hardware design of the nodes, which include an energy harvesting system. The system is capable of transmitting 7.5 bps per node at distances of about 100 m. The proposed system is considered a cost-effective and scalable solution for WSN in precision farming.