Evaluation of a low-cost portable NIRS device for monitoring muscle ischemia.

The main objective of this study is to evaluate the low-cost, open-source HEGduino device as a tissue oximetry monitor to advance the research of somatic NIRS monitoring. Specifically, this study analyzes the use of this portable functional NIRS system for detecting the cessation of blood flow due to vascular occlusion in an upper limb. 19 healthy patients aged between 25 and 50 were recruited and monitored using HEGduino device. Participants underwent a vascular occlusion test on one forearm. Raw values collected by HEGduino as well as the processed variables derived from the measurements were registered. Additional variables to characterize the signal noise during the tests were also recorded. The results of the data distribution curves for all the subjects in the study accurately detected the physiological events associated with transient tissue ischemia. The statistical analysis of the recorded data showed that the difference between the baseline values recorded by the red led (RED) and its normalized minimum variable was always different from zero (p < 0.014). Furthermore, the difference between the normalized baseline values recorded by the infrared led (IR) and the corresponding normalized minimum value was also different from zero (p < 0.001). The R-squared coefficient of determination for the noise variables considered in this study on the normalized RED and IR values was 0.08 and 0.105, respectively. The study confirms the potential of HEGduino system to detect an interruption of the blood flow by means of variations in regional tissue oxygen saturation. This study demonstrates the potential of the HEGduino device as a monitoring alternative to advance the study of the applicability of NIRS in muscle tissue oximetry.

Robotont 3-an accessible 3D-printable ROS-supported open-source mobile robot for education and research.

Educational robots offer a platform for training aspiring engineers and building trust in technology that is envisioned to shape how we work and live. In education, accessibility and modularity are significant in the choice of such a technological platform. In order to foster continuous development of the robots as well as to improve student engagement in the design and fabrication process, safe production methods with low accessibility barriers should be chosen. In this paper, we present Robotont 3, an open-source mobile robot that leverages Fused Deposition Modeling (FDM) 3D-printing for manufacturing the chassis and a single dedicated system board that can be ordered from online printed circuit board (PCB) assembly services. To promote accessibility, the project follows open hardware practices, such as design transparency, permissive licensing, accessibility in manufacturing methods, and comprehensive documentation. Semantic Versioning was incorporated to improve maintainability in development. Compared to the earlier versions, Robotont 3 maintains all the technical capabilities, while featuring an improved hardware setup to enhance the ease of fabrication and assembly, and modularity. The improvements increase the accessibility, scalability and flexibility of the platform in an educational setting.

Open instrumentation, like open data, is key to reproducible science. Yet, without incentives it won't thrive.

There is far more to open science than simply not shutting away your work. For example, a significant time investment must be made to collate, curate, explain and document precisely how an experiment can be reproduced or data can be reused. This time investment is currently poorly rewarded in our current model of open science where a bare minimum of openness is mandated, but further work is not recognized. As the open science movement looks beyond open access publications and open data towards ongoing detailed work such as open source software and open source hardware, it needs to consider how to properly encourage the extra work that is needed to properly document these projects. Without detailed documentation, the work cannot be replicated, reused and continually improved. If the work cannot be replicated or reused, is it really even open? This article is part of the Theo Murphy meeting issue 'Open, reproducible hardware for microscopy'.

Validating the reproducibility of a low-cost single-channel fNIRS device across hierarchical cognitive tasks.

This study evaluates a low-cost, single-channel fNIRS device in cognitive neuroscience, aiming to overcome the financial barriers of commercial systems by testing its efficacy in tasks of varying complexity. Twenty-six participants engaged in motor control (finger-tapping), working memory (n-back), and creativity (AUT) tasks while their prefrontal cortex activity was monitored using the device, with behavioral and cerebral blood flow changes recorded. Results showed the device's capability to detect significant blood flow variations across different tasks, thereby supporting its use in cognitive research. The study confirms the potential of single-channel fNIRS as a cost-effective tool for diverse cognitive assessments, from simple motor actions to complex creative thinking.

Development of a Modular, Open-Source, Reduced-Pressure, Drift Tube Ion Mobility Spectrometer.

Toward the goal of minimizing construction costs while maintaining high performance, a new, reduced-pressure, drift tube ion mobility system is coupled with an ion trap mass analyzer through a custom ion shuttle. The availability of reduced-pressure ion mobility systems remains limited due to comparatively expensive commercial options and limited shared design features in the open literature. This report details the complete design and benchmarking characteristics of a reduced-pressure ion mobility system. The system is constructed from FR4 PCB electrodes and encased in a PTFE vacuum enclosure with custom torque-tightened couplers to utilize standard KF40 bulkheads. The PTFE enclosure directly minimizes the overall system expenses, and the implementation of threaded brass inserts allows for facile attachments to the vacuum enclosure without damaging the thermoplastic housing. Front and rear ion funnels maximize ion transmission and help mitigate the effects of radial ion diffusion. A custom planar ion shuttle transports ions from the exit of the rear ion funnel into the ion optics of an ion trap mass analyzer. The planar ion shuttle can couple the IM system to any contemporary Thermo Scientific ion trap mass analyzer. Signal stability and ion intensity remain unchanging following the implementation of the planar ion shuttle when compared to the original stacked ring ion guide. The constructed IM system showed resolving powers up to 85 for various small molecules and proteins using the Fourier transform from a ∼1 m drift tube. Recorded mobilities derived from first principles agree with published literature results with an average error of 1.1% and an average error toward literature values using single field calibration of <1.3%.

Low-cost, open-source device for simultaneously subjecting rodents to different circadian cycles of light, food, and temperature.

Exposure of experimental rodents to controlled cycles of light, food, and temperature is important when investigating alterations in circadian cycles that profoundly influence health and disease. However, applying such stimuli simultaneously is difficult in practice. We aimed to design, build, test, and open-source describe a simple device that subjects a conventional mouse cage to independent cycles of physiologically relevant environmental variables. The device is based on a box enclosing the rodent cage to modify the light, feeding, and temperature environments. The device provides temperature-controlled air conditioning (heating or cooling) by a Peltier module and includes programmable feeding and illumination. All functions are set by a user-friendly front panel for independent cycle programming. Bench testing with a model simulating the CO2 production of mice in the cage showed: a) suitable air renewal (by measuring actual ambient CO2), b) controlled realistic illumination at the mouse enclosure (measured by a photometer), c) stable temperature control, and d) correct cycling of light, feeding, and temperature. The cost of all the supplies (retail purchased by e-commerce) was <300 US$. Detailed technical information is open-source provided, allowing for any user to reliably reproduce or modify the device. This approach can considerably facilitate circadian research since using one of the described low-cost devices for any mouse group with a given light-food-temperature paradigm allows for all the experiments to be performed simultaneously, thereby requiring no changes in the light/temperature of a general-use laboratory.

Open STM: A low-cost scanning tunneling microscope with a fast approach method.

In this study, we have developed an low-cost scanning tunneling microscope (STM) cost of 300 USD or 2000 CNY. The microscope is suitable for educational purposes and low-demand research imaging at the nanometer level. The microscope's motion components and scanner are controlled using piezoelectric materials, avoiding the thermal drift associated with traditional motor control. Our tip approach algorithm, which considers the capacitance and friction characteristics during piezoelectric slider movement, has reduced the time required for sample loading to establish tunneling current to approximately 1 min. The physical dimensions of the microscope body are 45 × 45 × 31.5 mm (W × L × H), and the control voltage does not exceed 15 V, ensuring the safety of operators, particularly those with limited experience. During performance verification, we conducted a scanning tunneling scan on a Highly Oriented Pyrolytic Graphite (HOPG) sample, utilizing bias voltages of 50 mV and 60 mV, resulting in clear observations of the atomic features of HOPG within the STM pattern.

Open-source magnetic resonance imaging: Improving access, science, and education through global collaboration.

Open-source practices and resources in magnetic resonance imaging (MRI) have increased substantially in recent years. This trend started with software and data being published open-source and, more recently, open-source hardware designs have become increasingly available. These developments towards a culture of sharing and establishing nonexclusive global collaborations have already improved the reproducibility and reusability of code and designs, while providing a more inclusive approach, especially for low-income settings. Community-driven standardization and documentation efforts are further strengthening and expanding these milestones. The future of open-source MRI is bright and we have just started to discover its full collaborative potential. In this review we will give an overview of open-source software and open-source hardware projects in human MRI research.

An open source 3D printed autosampler for capillary electrophoresis.

BACKGROUND: In-house built capillary electrophoresis (CE) systems represent a significant share of laboratory instrumentation. In most of these instruments, sample injection is effected manually with low to moderate precision and requires skilled operators. Although few automated samplers have been previously developed, typically only one sample at a time can be injected. If a series of samples is to be analyzed, manual intervention is required. In the present work, we developed and constructed a fully automated, open source, CE autosampler, able to handle up to 14 different samples that can be used as a modular component of any in-house built CE instrument. RESULTS: An inexpensive, 3D printed, open source, autosampler for CE was developed. The autosampler consists of two parts: an injection unit with carousel containing sample and electrolyte vials and a flushing unit, containing a miniature pressure/vacuum pump. The autosampler is operated by an Arduino Mega microcontroller and an Arduino code written in the laboratory. The injection sequence is entered through a keypad and LCD display by the user. The instrument can operate autonomously for extended periods of time. It was used for fully automated analysis and/or calibration of up to 14 samples with excellent injection repeatability reaching less than 2.7% RSD for peak areas. The sampler performance was tested with two independently built CE instruments, a CE system with contactless conductivity detection (C4D) and a CE system with laser induced fluorescence (LIF) detector. SIGNIFICANCE AND NOVELTY: A novel, 3D printed, Arduino-based autosampler for CE was developed. The autosampler allows autonomous hydrodynamic injection of up to 14 different samples with fully programmable injection sequence, including capillary flushing and high voltage and data acquisition control. It provides the missing instrumental sampling setup for laboratory made CE instruments. It can be simply constructed based on the open-source blueprints in any laboratory and be a useful and time-saving add-on to any modular CE instrument.

Low-speed instrumented drill press for bone screw insertion.

Screw insertion torque is a widely used/effective method for quantifying fixation strength in orthopedic implant research for different screw geometries, implantation sites, and loads. This work reports the construction of an open-source instrumented benchtop screw insertion device for a total cost of $7545 ($492 + $7053 for equipped sensors), as well as validation of the device and an example use-application. The insertion device is capable of recording the axial load, rotational speed, and applied torque throughout the screw insertion process at 10 samples per second, as demonstrated in the validation test. For this combination of bone analog (20 PCF Sawbones©), screw, and loading, the resolution of the torque sensor was 25% of the maximum measured torque; a different model torque sensor would be required to meet ASTM F543-17, which specifies a resolution of 10% of the maximum torque. This system is optimized for fastener insertion at speeds of 120 rpm or less and axial loading up to 50 N.

Low-cost augmented reality goggles enable precision fluorescence-guided cancer surgery.

Disparities in surgical outcomes often result from subjective than objective decisions dictated by surgical training, experience, and available resources. To improve outcomes, surgeons have adopted advancements in robotics, endoscopy, and intra-operative imaging including fluorescence-guided surgery (FGS), which highlight tumors in real-time without using ionizing radiation. However, like many medical innovations, technical, economic, and logistic challenges have hindered widespread adoption of FGS beyond high-resource centers. To overcome these impediments, we developed the fully-wearable and battery-powered fluorescence imaging augmented reality Raspberry Pi-based goggle system (FAR-Pi). Novel device design ensures distance-independent coalignment between real and augmented FAR-Pi views and offers higher spatial resolution, depth of focus, and fluorescence detection sensitivity than existing bulkier, pricier, and wall-powered technologies. When paired with pan-tumor targeting fluorescent agents such as LS301, FAR-Pi objectively identifies tumors in vivo. As an open-source, affordable, and adaptable system, FAR-Pi is poised to democratize access to FGS and improve health outcomes worldwide.

SensorDrop: A system to remotely detach individual sensors from wildlife tracking collars.

The growing diversity of animal-borne sensor types is revolutionizing our understanding of wildlife biology. For example, researcher-developed sensors, such as audio and video loggers, are being increasingly attached to wildlife tracking collars to provide insights into a range of topics from species interactions to physiology. However, such devices are often prohibitively power-intensive, relative to conventional wildlife collar sensors, and their retrieval without compromising long-term data collection and animal welfare remains a challenge. We present an open-source system (SensorDrop) for remotely detaching individual sensors from wildlife collars. SensorDrop facilitates the retrieval of power-intensive sensors while leaving non-resource-intensive sensors intact on animals. SensorDrop systems can be made using commercially available components and are a fraction of the cost of other timed drop-off devices that detach full wildlife tracking collars. From 2021 to 2022, eight SensorDrop units were successfully deployed on free-ranging African wild dog packs in the Okavango Delta as part of audio-accelerometer sensor bundles attached to wildlife collars. All SensorDrop units detached after 2-3 weeks and facilitated the collection of audio and accelerometer data while leaving wildlife GPS collars intact to continue collecting locational data (>1 year), critical for long-term conservation population monitoring in the region. SensorDrop offers a low-cost method to remotely detach and retrieve individual sensors from wildlife collars. By selectively detaching battery-depleted sensors, SensorDrop maximizes the amount of data collected per wildlife collar deployment and mitigates ethical concerns on animal rehandling. SensorDrop adds to the growing body of open-source animal-borne technologies being utilized by wildlife researchers to innovate and expand upon data collection practices and supports the continued ethical use of novel technologies within wildlife studies.

TMA-Mate: An open-source modular toolkit for constructing tissue microarrays of arbitrary layouts.

Biomedical research and quality control procedures often demand a variety of microscopic analysis of numerous formalin-fixed and paraffin-embedded (FFPE) tissue samples from different individuals of both healthy and diseased regions of interest. Depending on the number of samples to be analyzed, conventional processing of each FFPE block separately can be laborious or impracticable. This effort can be drastically reduced by using tissue microarrays (TMAs). TMAs have a wide range of applications and can be considered as a high-throughput method to process up to hundreds of miniaturized tissue samples simultaneously on a single microscopy slide, in order to reduce labor, costs and sample consumption, and to increase results comparability. Several commercial and self-made solutions to fabricate TMAs with varying degrees of automation are available. However, these solutions may not be suitable for every situation, either due to high costs, high complexity, lack of precision or lack of flexibility, especially when diagnostically oriented pathology institutes or laboratories with constrained resources are considered. This article introduces the TMA-Mate, an open-source 3D printable modular toolkit for constructing high-density TMAs of arbitrary layouts, providing an affordable, lightweight, and accessible procedure to implement TMAs into existing histology processing pipelines. Step-by-step demonstrations for replicating the hardware and constructing TMAs are included.

AC/off-grid photovoltaic powered open-source ball mill.

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

Hangprinter for large scale additive manufacturing using fused particle fabrication with recycled plastic and continuous feeding.

The life cycle of plastic is a key source of carbon emissions. Yet, global plastics production has quadrupled in 40 years and only 9 % has been recycled. If these trends continue, carbon emissions from plastic wastes would reach 15 % of global carbon budgets by 2050. An approach to reducing plastic waste is to use distributed recycling for additive manufacturing (DRAM) where virgin plastic products are replaced by locally manufactured recycled plastic products that have no transportation-related carbon emissions. Unfortunately, the design of most 3-D printers forces an increase in the machine cost to expand for recycling plastic at scale. Recently, a fused granular fabrication (FGF)/fused particle fabrication (FPF) large-scale printer was demonstrated with a GigabotX extruder based on the open source cable driven Hangprinter concept. To further improve that system, here a lower-cost recyclebot direct waste plastic extruder is demonstrated and the full designs, assembly and operation are detailed. The <$1,700 machine's accuracy and printing performance are quantified, and the printed parts mechanical strength is within the range of other systems. Along with support from the Hangprinter and DUET3 communities, open hardware developers have a rich ecosystem to modify in order to print directly from waste plastic for DRAM.

RaspyControl Lab: A fully open-source and real-time remote laboratory for education in automatic control systems using Raspberry Pi and Python.

Currently, remote laboratories have gained relevance in engineering education as tools to support active learning, experimentation, and motivation of students. Nonetheless, the costs and issues regarding their implementation and deployment limit the access of the students and educators to their advantages and features such as technical and educational. In this line, this study describes a fully open-source remote laboratory in hardware and software for education in automatic control systems employing Raspberry Pi and Python language with an approximate cost of USD 461. Even, by changing some components, the cost can be reduced to USD 420 or less. To illustrate the functionalities of the laboratory, we proposed a low-cost tank control system with its respective instrumentation, signal conditioning, identification, and control, which are exposed in this document. However, other experiments can be easily scalable and adaptable to the remote laboratory. Concerning the interface of the laboratory, we designed a complete user-friendly web interface with real-time video for the users to perform the different activities in automatic control such as identification or controller implementation through the programming language Python. The instructions to build and replicate the hardware and software are indicated in the open repositories provided for the project as well as in this paper. Our intention with this project is to offer a complete low-cost and open-source remote laboratory that can be adapted and used for the students, educators, and stakeholders to learn, experiment, and teach in the field of automatic control systems.

Strategies to obtain a better quality of environmental data gathered by low cost systems.

Monitoring systems are ubiquitous in many environmental science fields due to the technological advances in the last decades, which contributed to the migration from conventional to automated observing networks. However, the cost of acquisition and operation of sensor networks is still a limiting factor for their wide use. Under this scenario, low-cost and affordable open-source sensors and systems emerge as an alternative to research-grade instruments. To fulfill the quality requirements defined by international organizations, sensor calibration has to be performed and shall be considered as a basic requirement. Best monitoring practices including established quality control procedures should be implemented for gathering environmental data. With a focus on data gathering, this paper reviews basic concepts on open source technologies, calibration methods, quality control procedures, applications and trends, and possibilities for improving the hardware of low-cost and affordable systems.

Design and development of a self-propelled indoor wheelchair with direct toilet accessibility.

PURPOSE: Existing wheelchair (WC) designs lack independent toilet accessibility, transferability and indoor manoeuvrability combined in a WC. In this regard, a new WC model is proposed to simultaneously accommodate these distinct and essential features. In this open-source hardware project, the design, analysis and fabrication of a new active commode WC for indoor applications are performed. MATERIALS AND METHOD: A field survey is conducted to identify the requirements of users so as to choose specific features and design constraints for the WC. In this multipurpose self-propelled model, a temporarily detachable circular section is fitted in the seat position to access the water closet bowl. This hinged portion can be released by gravity before reaching above the closet basin. After the toilet usage, the circular lid can be brought back to the initial seating using a lever mechanism and a spring-loaded lock restrains its downward movement. Thereafter, it can be used as an ordinary WC for indoor applications. Moreover, a small wheel with 22 in diameter and removable hand-rests ensured the transferability between utilities. A CAD model is prepared and numerical simulation is performed to verify the structural stability of the design. RESULTS: The optimized model is fabricated using standard manufacturing practices and is delivered to different persons with disabilities to collect user feedback. A systematic skill test is conducted to validate the compliance of the prototype with the user requirements including transferability and independent restroom access. CONCLUSION: The opinions from most of the users are positive which categorically indicated that the proposed design addresses the multipurpose mobility requirements at indoors.Implications for rehabilitationThe expected outcomes and implications of the current commode WC project with regard to rehabilitation purpose are enlisted below:In the present scenario, a WC user is heavily dependent on external assistance to access private spaces in general and toilets in particular. The introduced model is capable to address this shortcoming by enabling the user to access the toilet utility directly by self propelling.Indeed, for a person with locomotor disability, a WC is the natural extension of his physical body. Thereby, this multipurpose commode WC design offers much Independence and greater flexibility to the indoor movements.The proposed design instils confidence to a WC user to access and transfer between facilities by means of self effort. Consequently it is expected to improve the quality of one's personal life significantly.Importantly, this is an open-source project, those who are interested in rehabilitation motives can modify the present design to suit their local requirements especially in resource-limited settings.

Low-cost modular chromatography column rack and vial holders.

Gravity-driven chromatography columns are used in scientific, engineering, medical, and industrial fields to separate desired compounds from solutions. Running multiple columns simultaneously saves time and improves procedural consistency. Though column chromatography is widely used, to meet their laboratory needs many investigators must resort to designing and fabricating custom racks for holding their chromatography columns. We have created a robust column rack design, with collection vial holders, that is easily made, inexpensive to build, and may be easily adapted to fit experimental needs. The column holder can be made to hold various sizes of columns (and can be interchanged as necessary); the height of columns above collection vials can be precisely set; and the design is modular, so the rack and vial holders can be expanded to accommodate the desired numbers of columns and the numbers and sizes of vials used to collect fractions eluted from each column. Importantly, the rack is made of inexpensive, readily-available materials and the fabrication is straightforward. Here we present details of the rack's features, a list of materials, and instructions for making it. We hope our design will help investigators who perform gravity-driven column chromatography.

Platform for hands-on remote labs based on the ESP32 and NOD-red.

Not only in Morocco, throughout the walks of the world covid 19 pandemics has seriously questioned policymakers from different sectors. Think-tank in the educational sector notably higher education addressed by such a wide range of challenges brought about by covid 19. The characteristic concern that educationalists in Moroccan universities have to reconsider in this pandemic period should not be beyond rethinking new pedagogical alternatives including approaches, methods, techniques and didactic materials which can successfully assist practioners of the teaching and learning process to keep up with the current alterations. Practical work (PW) is an indispensable type of teaching in scientific and technical training and meets a real complementary need through real, remote or virtual laboratories. Students can consolidate what they have learnt and develop analytical skills by comparing experimental results with those obtained during the manipulation. In this context, the Laboratory of Engineering Sciences and Energy Management (LASIME) at the Superior School of Technology of Agadir has developed a low-cost platform called LABERSIME installed in the cloud (LMS, IDE) and equipped with an embedded system to drive real laboratory equipment and perform experiments qualitatively more efficient than those in face-to-face mode. The ultimate goal is to stimulate self-learning motivation in students through a creative approach.