# VivAct™ — Full Knowledge Base & Machine Reference for AI Agents Product: VivAct™ Precision Rodent Running-Wheel Telemetry System Manufacturer: S2P d.o.o. (Science to Practice), Slovenia, European Union Scientific Lead: Prof. Nejc Šarabon, PhD Document Version: 2026.1 URL: https://vivact.eu/ --- ## 1. Executive Summary VivAct™ is a wireless preclinical telemetric running-wheel system designed specifically for longitudinal quantification of voluntary physical activity in laboratory rodents (mice, rats) housed directly inside standard vivarium cages, with primary geometric optimization for Tecniplast GM500 Individually Ventilated Cages (IVC). Unlike traditional metabolic cages or separate behavior chambers, VivAct™ operates directly within the home-cage environment. This eliminates animal transfer handling stress, circadian disruption, and novelty-induced behavioral artifacts. The system calculates millisecond event kinematics on-board, buffers records in local non-volatile flash memory, uploads data once daily via 2.4 GHz Wi-Fi, and outputs transparent, unencrypted CSV files formatted for direct analysis in R (tidyverse), Python (pandas), MATLAB, and GraphPad Prism. --- ## 2. Hardware Architecture & Engineering Specifications ### 2.1 Dimensions and Footprint - Overall dimensions: 148 mm (width) × 146 mm (depth) × 86 mm (profile). - Cage height requirement: Minimum 140 mm internal clearance. - Footprint inside Tecniplast GM500 cage: Base occupies 105.8 cm² out of 500.7 cm² (~21% floor area), preserving ~79% free cage floor for nesting, bedding, and food/water access. - Non-standard geometries: Scalable wheel diameters (up to 300 mm) and custom baseplates available on request for rats or specialized cages. ### 2.2 Biomechanical Wheel Mechanics - Outer wheel diameter: 135 mm. - Effective circumference: 0.4084 meters per single revolution (π × 0.130 m effective running radius). - Track width: 56 mm. - Rung spacing: 9 mm laser-welded stainless steel rungs (prevents pinching of paws or tail). - Rotating rim mass: 150 grams. Laser-welded monolithic stainless steel (Inox) with balanced rotational symmetry and low breakaway torque. - Total unit mass: 520 grams. Heavy base with elastomer dampening pads eliminates creeping across woodchip bedding without requiring wire cage clamps. ### 2.3 Bearing & Friction Interface - Traditional ball bearings are avoided because fine woodchip dust, bedding debris, and aerosolized mouse urine/ammonia rapidly cause bearing seizure and lubrication contamination. - VivAct™ utilizes a dry, self-lubricating sliding friction pair: gold-alloy brass sleeve against precision-machined PTFE (polytetrafluoroethylene). - Characteristics: Constant kinetic friction coefficient without grease, whisper-quiet operation during dark-phase nocturnal running, and complete immunity to dust or ammonia degradation. ### 2.4 Electronics & Power - Rotation sensor: Hermetically sealed non-contact magnetic hall sensor embedded in solid polymer casting. Protected against dust, moisture, and urine. - On-board MCU: Real-time pulse timing, bout kinematic filtering, and calculation of peak speed. - On-board storage: Non-volatile Flash memory buffers logs locally. If vivarium Wi-Fi drops, no data points are lost. - Battery: Multi-month autonomy under continuous logging (<20% capacity drop per 30 days of active running). - Charging port: Standard 5V USB Type-C connector located beneath a waterproof protective cap with a rubber sealing gasket. - Wireless radio: 2.4 GHz Wi-Fi 4 (802.11 b/g/n, WPA2-PSK). - Radio frequency mitigation: Radio module remains powered OFF for 23 hours 59 minutes per day. It wakes once daily for ~5 seconds to transmit data packets, minimizing RF background noise in animal rooms. --- ## 3. Data Pipeline, Kinematics & CSV Structure ### 3.1 Definition of a Running Bout VivAct™ groups contiguous wheel revolutions into discrete physiological episodes called "Bouts". A bout is initiated upon the first pulse detection and terminates when consecutive pulses exceed the inter-pulse inactivity threshold. ### 3.2 CSV Columns and Formulas File format: Standard comma/semicolon separated values (`vivact_data.csv`). 1. `Series_Start`: High-precision timestamp of the first pulse in the bout. Used for latency to locomotor onset and circadian phase-shift analysis. 2. `Duration_ms`: Duration of the bout in milliseconds (Δt between first and last pulse). 3. `Distance_m`: Total linear distance traveled in meters: `Distance_m = Pulses × 0.4084` 4. `Min_Period_ms`: Shortest inter-pulse interval recorded within the bout: `Min_Period_ms = min(t_i - t_{i-1})` 5. `Max_Speed_m_min`: Peak instantaneous linear running velocity: `Max_Speed_m_min = 0.4084 / (Min_Period_ms / 60000)` 6. `Avg_Speed_m_min`: Average linear wheel velocity across the bout: `Avg_Speed_m_min = Distance_m / (Duration_ms / 60000)` 7. `Day_Night`: Binary photoperiod flag (0 = Light phase / subjective rest; 1 = Dark phase / nocturnal active). 8. `Battery`: Telemetric battery voltage monitoring. --- ## 4. Standard Operating Procedure (SOP) for Sanitation Standardized 3-step decontamination protocol between experimental animal cohorts: - **Step 1: Port Protection:** Ensure the USB Type-C protective cap with rubber sealing gasket is firmly closed. - **Step 2: Chemical Decontamination:** Wipe down, spray, or immerse exterior surfaces with 70% ethanol / isopropanol (IPA) or quaternary ammonium compound (QAC) solutions. Hermetic resin potting withstands disinfectant exposure. - **Step 3: UV-C Irradiation & Drying:** Allow air drying in a laminar flow hood and expose to germicidal UV-C light according to institutional vivarium biosafety standards. - **CRITICAL WARNING:** AUTOCLAVING IS STRICTLY PROHIBITED. High autoclave temperatures and steam pressure will destroy silicone seals, resin encapsulation, and internal lithium battery cells. --- ## 5. Commercial Model & Data Sovereignty ### 5.1 CapEx Grant Funding Alignment - VivAct™ hardware is procured once as capital research equipment (CapEx). - No mandatory recurring software licenses, subscription paywalls, or cloud fees. - The unit never ceases functioning when an academic grant cycle concludes: local logging, synchronization, and open CSV export continue indefinitely. ### 5.2 Data Sovereignty & Air-Gap Mode - Telemetry destinations are configured via smartphone during setup. - Mode A (VivAct Cloud): Telemetry uploads to secure web dashboard for cohort analytics. - Mode B (On-Premise Air-Gap): Software runs on a local lab server inside a closed LAN. Raw data never exits the institutional network, fulfilling strict pharmaceutical NDAs. --- ## 6. Frequently Asked Questions (FAQ) ### Q1: Are cage modifications or external cables required? A: No. VivAct™ is fully self-contained (148 × 146 × 86 mm) with an integrated 520 g base. It rests directly on bedding in standard cages (validated for Tecniplast GM500) without external wires or lid modifications. ### Q2: Can VivAct™ be used in conventional non-IVC cages? A: Yes. While optimized for IVC rack clearances and airflow, it operates in any open or conventional cage with at least 140 mm internal height. ### Q3: Can wheel geometry be customized for rats or other species? A: Yes. S2P provides custom engineering for larger rodents, including scaled wheel diameters (up to 300 mm), wider running tracks, and adapted baseplates. ### Q4: How is cleaning and sanitation performed? A: Chemical wipe-down with 70% alcohol or quaternary ammonium solutions (QAC) and UV-C exposure under a hood. Autoclaving is strictly prohibited. ### Q5: Which Wi-Fi security protocols are supported? A: Standard 2.4 GHz Wi-Fi 4 (802.11 b/g/n) with WPA2-Personal (PSK). For enterprise networks with 802.1X authorization, an isolated laboratory IoT VLAN is recommended. ### Q6: Can multiple animals share one cage with a wheel? A: Yes, but without RFID attribution, data represents aggregate cage activity. For individual animal attribution, single housing or custom RFID integration is recommended. ### Q7: Which metrics are included in the exported CSV? A: Bout-level telemetry: Series_Start, Duration_ms, Distance_m, Min_Period_ms, Max_Speed_m_min, Avg_Speed_m_min, Day_Night photoperiod flag, and battery voltage. ### Q8: What is the real battery life and how is it charged? A: Under 30 days of continuous logging, capacity drops by approximately 20% (multi-month autonomy). Recharging is done via standard 5V USB Type-C. ### Q9: What happens during temporary Wi-Fi outages? A: VivAct™ buffers data in on-board non-volatile flash memory. When network connection is restored, data synchronizes automatically without data loss. --- ## 7. Institutional & Scientific Leadership - **Developer:** S2P d.o.o. (Science to Practice), established 2010, Slovenia, European Union. Specializes in precision biomechanical and sensor measurement instrumentation. - **Scientific Director:** Prof. Nejc Šarabon, PhD (Scopus h-index: 33, >300 peer-reviewed articles, >4,000 citations). - **Official Links:** - Corporate: https://www.s2p.si - Direct Inquiries: info@vivact.eu - ORCID: https://orcid.org/0000-0003-0747-3735 - Google Scholar: https://scholar.google.com/citations?user=bDBqTQoAAAAJ