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Certiter
Cericom: engineering the next-generation gait sensor electronics for Ceriter's Stride One platform
Voxdale partnered with Ceriter to design and develop the next-generation Cericom — the embedded electronics and firmware core of the Stride One gait improvement platform — engineering a miniaturised, IP68-rated device that streams precise gait data from 8 pressure sensors and a 6-axis IMU to a smartphone via BLE 5.0.
Executive Summary
Ceriter's Stride One platform helps people with gait disorders recover through real-time biofeedback. The intelligence of the system lives in a small module — Cericom — that sits on the insole, reads eight pressure sensors and an IMU, and streams precise gait data to a smartphone.
The first-generation Cericom worked. The brief for the next generation was to rebuild it: smaller, more capable, certifiable, and designed to last a full day on a single charge.
Voxdale owned the full embedded engineering stack — PCB design, BLE 5.0 firmware, sensor integration, housing, prototyping, and certification support. The constraints were non-negotiable and could not be solved in sequence: clinical measurement accuracy, a 24-hour battery, a coin-sized IP68 housing, and rock-solid BLE connectivity across every major smartphone chipset.
The result is a device engineered to carry Stride One into clinical and commercial scale.
Client Context
Ceriter is the company behind Stride One, a gait improvement platform designed for people recovering from neurological or musculoskeletal conditions that affect the way they walk. The system combines an instrumented insole, a connected electronics module (Cericom), a smartphone application, and a web portal for clinicians.
Stride One works by collecting high-frequency pressure and motion data from the insole during a patient's gait cycle and using that data to provide real-time biofeedback. The goal is to give both patient and clinician an objective, continuous picture of gait quality — and to use that picture to accelerate recovery.
When Voxdale joined the Cericom development, the first-generation device was already proven in clinical use. Ceriter needed a next-generation module that could be manufactured reliably, certified for the markets they were targeting, and extended with new capabilities — without disrupting the clinical workflow that clinicians and patients had come to depend on.
The Brief
The technical brief.
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Replace the existing Cericom electronics and firmware with a next-generation device
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Maintain full backward compatibility with the Stride One insole and smartphone application
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Extend capability: higher sampling rate, improved sensor accuracy, larger FSR sensor array, more reliable BLE streaming
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Design the housing for IP68 sealing and clinical durability
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Support CE and FCC pre-compliance processes
The harder, less obvious part.
The brief carried a set of constraints that all pulled against each other and could not be solved in sequence:
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Form factor. The device had to fit within 3.5 × 3.5 × 1 cm — a space that leaves almost no room for compromise in component selection, PCB layout, or battery sizing.
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Battery life. Twenty-four hours of continuous data transmission from a battery that had to live inside that centimetre of depth and recharge in under eight hours.
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Measurement accuracy. The IMU had to deliver factory- or software-calibrated outputs for step length, step height, velocity, and joint angles — the clinical metrics Ceriter's software and clinicians depend on. Any drift or noise directly affects patient outcomes.
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Connectivity reliability. BLE streaming had to be stable across Qualcomm, Exynos, MediaTek, Google and Apple smartphone chipsets — the full range of what patients and clinicians actually use.
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IP68 sealing. The device lives on a foot. It gets wet, compressed, and dropped. The sealing approach had to be integrated from the start, not added at the end.
Ceriter needed a partner that could hold all five constraints together from the first PCB layout — not hand off electronics to one subcontractor, firmware to another, and housing to a third.
What Voxdale Delivered
Voxdale owned the full embedded engineering stack from architecture to functional prototype.
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PCB design. A custom PCB designed from scratch — component selection, layout, and routing driven by form factor, power budget, and clinical accuracy requirements simultaneously. The design supports 8-channel FSR sensor readout, a 6-axis IMU (accelerometer + gyroscope, with optional magnetometer), BLE 5.0, USB-C charging, micro-SD local storage, and a multi-colour LED array — all within the target footprint.
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Embedded firmware. Full firmware development including BLE communication stack, sensor sampling and data packaging, streaming and local storage modes, battery management, LED state logic, and remote OTA (over-the-air) firmware update via BLE. Sampling rate is configurable between 25 Hz and 100 Hz; packet size adjustable between 1 and 5 samples. Fully backwards-compatible with the existing Stride One BLE communication protocol.
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Sensor integration and calibration. Integration of the IMU with factory and software calibration to deliver reliable gait metrics — step length, step height, velocity, and limb and joint angles — across the full range of patient gaits and walking conditions.
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FSR sensor interface. An 8-channel force-sensitive resistor interface designed to maintain consistent, battery-voltage-independent readout from the insole's pressure sensors throughout the full charge cycle.
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Power management. A power architecture sized for a minimum 24-hour continuous operation target from a USB-C-charged battery, with accurate real-time battery monitoring reported via BLE.
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Housing and mechanical integration. Design of the housing and mechanical interface between Cericom and the insole — including connector approach (USB-C or bayonet-style), sealing for IP68 compliance, and form-factor constraints. Prototyped and iterated in Voxdale's in-house workshop.
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Prototype production. Functional prototypes produced and assembled using Voxdale's in-house PCB prototyping equipment, including PCB proto milling machine, reflow oven, and electronics workshop.
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Certification support. Support for CE marking and FCC compliance, including pre-compliance test preparation and the documentation and traceability infrastructure required for regulatory submission — with firmware and hardware revision information accessible via BLE characteristic.
How We Worked
A focused team of senior embedded engineers, working close together, with the prototype lab in the same building.
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Product navigator — overall direction, technical decision-making, primary point of contact for Ceriter.
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Electronics engineer — PCB architecture, component selection, layout, and power management.
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Firmware engineer — BLE stack, sensor drivers, data handling, OTA update, and clinical protocol alignment.
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Mechanical engineer — housing design, sealing strategy, connector approach, and insole integration.
The team held weekly remote alignment meetings with the Ceriter team and ran fast PCB-assemble-test loops in-house. Prototyping materials and first-article boards came off Voxdale's own equipment before any external manufacturer was involved. That speed is what made it possible to discover and resolve the interaction between form factor, power budget, and BLE reliability early — rather than after the architecture was committed to.
The Hardest Challenge — and How We Solved It
The challenge.
Fitting clinical-grade gait measurement, 24-hour battery life, IP68 sealing, and BLE connectivity for all major smartphone chipsets into 3.5 × 3.5 × 1 cm — and keeping all four constraints in balance at the same time.
Why it was difficult.
Each constraint normally pushes the design in a different direction. A larger battery requires more space and a different housing strategy. More accurate sensors require more processing and more power. IP68 sealing requires specific connector and housing interface approaches that affect the mechanical envelope. BLE reliability requires antenna placement that PCB layout and housing material selection can disrupt. These dependencies are real — resolve one naively and you compromise another.
What would not work.
Standard development sequencing — electronics, then housing, then firmware, then certification — would have produced a device that hit some of the constraints and revealed the others too late to fix without a full redesign.
What we changed:
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Co-design of PCB and housing from the first concept. Electronics layout and mechanical envelope were developed together, so the constraints on each informed the other from the start. The connector approach, sealing strategy, and battery geometry were part of the PCB architecture conversation, not a downstream integration problem.
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Power budget as a first-class design input. The 24-hour target was used as a constraint on component selection and sampling logic from the first component choices — not estimated after the architecture was set.
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BLE stack testing across chipset families early. Connectivity reliability across Android and iOS chipset variants was tested on early firmware builds, before streaming protocol decisions were locked in.
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In-house prototyping for fast iteration. Boards were milled, assembled, and tested in Voxdale's own electronics workshop. Issues at the intersection of PCB layout, firmware, and power behaviour were found and resolved in days rather than weeks.
Outcome
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Next-generation Cericom PCB and firmware designed and prototyped.
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8-channel FSR sensor readout and 6-axis IMU integrated with clinical gait metric calibration.
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BLE 5.0 data streaming at a configurable 25–100 Hz sampling rate, with local micro-SD storage fallback.
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24-hour battery life, USB-C charging, IP68 sealing, and 3.5 × 3.5 × 1 cm form factor achieved.
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Remote OTA firmware update and full BLE-accessible traceability implemented.
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CE/FCC pre-compliance process initiated.
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All IP — design files, firmware, and source code — owned fully by Ceriter.
What This Proves for Similar Teams
Cericom is relevant for founders and product owners in MedTech, digital health, or wearable sensing who are rebuilding or scaling a first-generation embedded device — where clinical accuracy, regulatory certification, miniaturisation, and battery life all have to be solved together, and where the engineering has to stay compatible with an existing clinical workflow and user base.
This case shows how Voxdale runs that kind of project: electronics, firmware, and mechanical integration inside one team; in-house prototyping fast enough to resolve cross-domain trade-offs before the architecture is locked; and a product navigator who stays close to both the clinical brief and the engineering constraints throughout.
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