Photosynthetically active radiation (PAR) is crucial for plant growth, influencing photosynthesis efficiency and crop yield. The increasing adoption of controlled-environment agriculture (CEA) necessitates precise PAR monitoring. The high cost of commercial PAR sensors, however, limits their accessibility and widespread use, creating a growing need for a low-cost alternative capable of reliable deployment in diverse agricultural environments. Building on recent advancements in PAR sensing using multi-channel spectral sensors such as the AS7341 and AS7265, this study develops the electronics for an AS7341-based, open-source, cost-effective (~USD 50) PAR sensor validated across a broad PPFD range and conditions, ensuring reliability and ease of replication. It uses a relatively simple multi-linear regression that offers real-time applications without energy intensive machine learning. The developed sensor is calibrated against the industry-standard Apogee SQ-500SS PAR sensor in four distinct farming environments: (i) horizontal grow lights, (ii) vertical agrotunnel lighting, (iii) agrivoltaics, and (iv) in greenhouses. A mean error ranging from 1 to 5% indicates its suitability for controlled environment farming and continuous data logging. The open-source hardware design and systematic installation guidelines enable users to replicate, calibrate, and integrate the sensor with minimal background in electronics and optics.

Initially the concept of a DC nanogrid was focused on supplying power to individual homes. Techno-economic advances in photovoltaic (PV) technology have enabled solar PV stand-alone nanogrids to power individual devices using device-specific architectures. To reduce costs and increase accessibility for a wider range of people, a modular open-source system is needed to cover all applications at once. This article introduces a modular PV-powered nanogrid system, consisting of a do it yourself (DIY) PV system with batteries to allow for off-grid power. The resultant open-source modular DC nanogrid can deliver DC power to loads of different voltage levels, which is possible because of the efficient and parametric energy management system (EMS) that selects modes of operation for the grid based on DC bus voltage and state of charge of batteries. Simulation results verify the coordination between the EMS and the PV-battery system under varying PV power generation and load conditions. This EMS has potential to enable easy personalization of a vast area of applications and expand appropriate technology for isolated communities. A thorough stability analysis has been conducted, leading to the development of an LQR (Linear Quadratic Regulator) controller as a replacement for the conventional PI (Proportional - Integral) controllers for better transient stability of the system.

Ball milling is used for comminution by rotating a drum to grind materials using balls with specific diameters. Ball milling advantages include the potential for high capacity, predicted fineness in a specific amount of time, reliability, safety, and simplicity, but has disadvantages of high weight, energy consumption and costs, which limit accessibility. To overcome these limitations this study applies the free and open source hardware approach coupled to distributed digital manufacturing to fabricate a ball mill with a simple, customizable design that can be used in a wide range of scientific applications and circumstances including those without access to reliable grid electricity. The highly-customizable design reduces the cost to <US$130 for an AC powered version and <US$315 for a switchable power that enables off-grid operation with a solar module and battery. Using a solar photovoltaic energy source not only improves the power reliability, but also makes it easier to move the ball mill for use in field environments. The open source ball mill is capable of reducing silicon particle sizes from the millimeter scale down to the nanometer scale.

Non thermal plasmas created by dielectric barrier discharge can break down methane directly to constituent elements without carbon dioxide emissions to produce a high-purity hydrogen and byproduct of solid carbon. To fulfill the environmental promise of plasma generators they must be powered with sustainable energy sources such as solar photovoltaic (PV) systems. There is a need to overcome the limitations of past approaches to power plasma systems to develop a completely open source solar PV system design capable of providing the necessary high-quality power. To overcome this research gap, this article provides a customizable open-source PV-powered design for plasma generators, which allows off-grid operation. This design facilitates the modification of existing lab-grade plasma generator setups into portable solar-powered systems. The open source inverter provides for AC loads at both 120 V and 230 V and has an acceptable total harmonic distortion of 3.58 %. The system was successfully able to power plasma generation and produce high quality plasmas with methane. Plasma generators are highly sensitive to any input voltage variation and power oscillation and the open source system provided higher power applied to the plasma reactor, which resulted in increased CH₄ conversion by 60.5 % and H₂ production 44.7 % compared to grid supply.

Harnessing solar energy offers a sustainable alternative for powering electrolysis for green hydrogen production as well as wastewater treatment. The high costs and logistical challenges of electrolysis have resulted in limited widespread investigation and implementation of electrochemical technologies on an industrial scale. To overcome these challenges, this study designs and tests a new approach to chemical experiments and wastewater treatment research using a portable standalone open-source solar photovoltaic (PV)-powered station that can be located onsite at a wastewater treatment plant with unreliable electrical power. The experimental system is equipped with an energy monitoring data acquisition system. In addition, sensors enable real-time monitoring of gases—CO, CO₂, CH₄, H₂, H₂S, and NH₃—along with temperature, humidity, and volatile organic compounds, enhancing safety during electrochemical experiments on wastewater, which may release hazardous gases. SAMA software was used to evaluate energy-sharing scenarios under different grid-connected conditions, and the system can operate off the power grid for 98% of the year in Ontario, Canada. The complete system was tested utilizing a laboratory-scale electrolyzer (electrodes of SS316L, Duplex 2205, titanium grade II and graphite) with electrolyte solutions of potassium hydroxide, sulfuric acid, and secondary wastewater effluent. The electrolytic cell specifically developed for testing electrode materials and wastewater showed a Faraday efficiency up to 95% and an energy efficiency of 55% at STP, demonstrating the potential for use of this technology in future work.