Jellyfish biologging remains challenging due to the animals’ fragile morphology, weak buoyancy, and the absence of dedicated tracking devices. This work presents the Jellyfish float tracker, an open-source floating electronic tag and associated data infrastructure designed for jellyfish tracking and recovery. The system combines a lightweight 3D-printed waterproof float, a low-power GNSS receiver, a LoRaWAN communication transceiver, and an end-to-end data processing pipeline based on The Things Network, MQTT, Node-RED, and InfluxDB. The tag periodically acquires and transmits surface positions while storing GNSS data locally. The position transmission enables to recover the animal and the tag, while the position storage in the tag memory is used to avoid data loss due to temporary unavailable radio coverage. All hardware design files, firmware, and software resources are released under open-source licenses to enable reproduction and customization. The complete platform was validated during field deployments in a coastal lagoon, where up to 12 tags were operated simultaneously through a dedicated LoRaWAN infrastructure. Deployment durations ranging from 1 h to 96 h were demonstrated, enabling live monitoring, trajectory reconstruction, and tagged animal recovery. This open hardware platform provides a reusable solution for jellyfish biologging applications and can be adapted to other lightweight floating animal-tracking scenarios.
Portable elemental analysis requires compact, low-cost plasma excitation sources that, unlike Atomic Absorption Spectroscopy and Inductively Coupled Plasma–Optical Emission Spectroscopy, can operate outside the laboratory. This article presents PenPlasma, a point-discharge microplasma source integrating a commercial high-voltage flyback module, an 18,650 lithium-ion battery, and pen-tip electrodes in a 3D-printed holder. The system delivers 4.9 ± 0.4 kV peak-to-peak (mean ± SD, n = 5) at 58 ± 3 kHz, costs US$6.03, and draws 3.4 ± 0.3 W during discharge, sustaining 1.4–1.75 h of continuous discharge per battery charge. Among electrode gaps of 0.5–2.5 mm, a 1.5 mm gap gave the longest discharge duration (163.4 ± 18.4 s) and the lowest trial-to-trial variation (CV = 11.3 %, n = 5) while retaining 85.4 % of the emission intensity at the shortest gap. Optical emission spectra (185–878 nm) show N2 and N2+ bands in air and resolve Ar I atomic lines when argon is fed through the hollow electrode, confirming that the source excites neutral atoms. PenPlasma is intended as the excitation stage of future point-of-care elemental detection; no analyte was introduced in this work. All design files are openly available.
The rising global incidence of stroke necessitates accessible and effective upper-limb rehabilitation solutions. However, the widespread adoption of commercial rehabilitation robots is often hindered by prohibitive costs, complex setups, exposed wiring hazards, and the financial burden of requiring dedicated left- or right-arm systems. This paper presents ARM-01, a cost-effective, open-source, 2-degree-of-freedom (DOF) rehabilitation robot engineered for passive range-of-motion and predefined trajectory tracking of the shoulder and elbow joints. Built using highly accessible off-the-shelf (OTS) components, 3D-printed parts, standard aluminum profiles, and SUS304 stainless steel, the hardware is specifically designed for straightforward replication. To maximize economic viability and clinical adaptability, the ARM-01 features a tool-free reversible mechanism, allowing a single unit to seamlessly alternate between left- and right-side upper-limb rehabilitation. Furthermore, the system incorporates a hollow-shaft internal cable-routing strategy that reduces exposed wiring and associated entanglement risks. Biomechanical alignment between the robot and the user’s glenohumeral joint is facilitated through a combination of a mobile base and a motorized lifting column, enabling convenient adjustment of the robot’s position relative to the user. The system’s hierarchical control architecture integrates a ROS2-based backend with an intuitive Unity 3D human–machine interface (HMI), facilitating tailored trajectory execution, real-time spatial monitoring, and multi-layered safety protocols. Comprehensive kinematic modeling, workspace simulation, and static load analyses theoretically evaluate the system’s actuator torque adequacy and safety boundaries. Successful operational testing in a controlled laboratory setting demonstrates the prototype’s basic operational feasibility under non-clinical conditions, offering the research community an adaptable and reproducible platform for further development of upper-limb rehabilitation technologies.
Simple three-axis gantry-based robots are widely used in laboratory automation due to their low cost, ease of implementation and flexibility. However, solid sample manipulation tasks that are intuitive for human operators, such as positioning and reorientation, often require motion capabilities beyond those of standard gantry systems, limiting the implementation of more advanced, uninterrupted automated experiments. Dexterous movements can be achieved using robotic arms or advanced motor systems, but with substantially increased system integration complexity and cost. This work presents a low-cost substrate handling and rotation module that enables passive degree-of-freedom augmentation in existing three-axis gantry-based automated workflows, addressing a key manual handling bottleneck. The modular pick-and-place hardware leverages the existing linear motion of an Opentrons OT-2 gantry to drive a rack-and-pinion mechanism, thereby enabling repeatable 180° rotational motion about a horizontal axis without the need for additional motors, electronics, or an external robotic system. We demonstrate this module in the automated manipulation of contact lens hydrogels for wettability characterization assays, though this platform can be used in broader laboratory automation applications including sample repositioning for microscopy or coating formation.
Incubation of biological samples in the field, far away from a laboratory, requires a portable, rugged, battery-powered incubator. The Moonrat II is a $225 open-source software and open-source hardware incubator constructed from a stainless steel vacuum flask and a microcontroller that can be powered by widely used external lithium-ion battery packs. It can be manufactured with modest skills and readily available tools. A three-button interface and an OLED display provide configurability and an ongoing graph of temperature to provide confidence in the incubation. A complete one-minute-resolution history of the internal temperature during an experiment can be downloaded via the serial port after the experiment. Measurements of the spatial consistency of the temperature are provided, as well as temperature stability over 48 h. A formula for battery life is provided based on power consumption measurements at room temperature and at refrigeration temperature. A statistical comparison with a commercial desktop incubator using 3M E. coli Petrifilms™ was performed, demonstrating a mean ratio of 1.076 between the two incubators. Due to the high variability of the measurements, this was statistically insufficient to establish equivalence or a difference between the incubators.
