HARDWARE · THE OVERGUARD S1

Smart PPE for every worker on every site.

The Overguard S1 is a sensor pod that clips to any EN 397 safety helmet in thirty seconds. It detects falls, impacts, zone breaches and SOS, and streams environmental conditions to your platform in real time.

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DETECTION CAPABILITIES

Seven kinds of safety event, on every helmet, all the time.

Falls and man-down
6-axis IMU fires within 200ms. On-device ML rejects the everyday motion that looks like a fall but isn’t.
Zone breaches
GNSS plus indoor BLE positioning. Geofenced exclusion zones trigger the moment a worker crosses the line.
Impact events
High-G detection logs every sudden event. Vehicle filtering keeps haul-truck rides out of the alert queue.
SOS
Deliberate 1.5-second hold of the side button. No accidental activations from a knock or a glove brush.
Lone worker check-ins
Automatic prompts when a worker has been isolated past the configured threshold. Escalates on a missed reply.
Environmental monitoring
Temperature, humidity, noise (dB-A), and air quality (PM2.5 / PM10) — sampled and streamed continuously.
BLE gas integration
Pairs with external detector brands at the worker level. Their reading lands inside the Overguard alert pipeline.
CONNECTIVITY

Always reaching the platform — even when the site can’t.

LTE-M / NB-IoT (primary)
Embedded SIM, low-power, and sub-3-second alert delivery on the LTE-M industry benchmark.
4G LTE (fallback)
Automatic failover when LTE-M is unavailable. Workers never drop off the platform.
LoRaWAN
Up to 15km range with a site gateway, for remote and underground-adjacent locations.
Bluetooth 5.2
Local mesh, indoor positioning via anchor beacons, and BLE gas sensor pairing — all from the same radio.
LIVE ON THE MAP

Every worker, every site, all the time.

  • Outdoor. u-blox M10 GNSS receiver with GPS, GLONASS and Galileo — 2–3m accuracy in clear sky, re-acquired in seconds when a worker steps out from cover.
  • Indoor. Bluetooth 5.2 mesh positioning via anchor beacons — the same workers are tracked through basements, stairwells, and steel-framed structures where GNSS won’t reach.
CERTIFICATIONS

Built for the standards your workforce already runs on.

EN 397 (helmet integration)ANSI/ISEA Z89.1IP67 (dust + water resistance)ATEX Zone 2 (explosive atmospheres)IECExCE + UKCAMIL-STD-810H (drop and shock)2-metre drop rated
POWER · PROVISIONING

10 hours of battery, 4 minutes from box to live on the map.

Power

1,800mAh LiPo cell. 10–12 hours in full-sensor mode. 14+ hours in extended mode. 80% charge in 45 minutes via the magnetic pogo-pin dock — a single overnight charge takes a pod through a full shift the next day.

Provisioning
  1. 01Clip the S1 to the rear band of any EN 397 helmet.
  2. 02Scan the QR code on the back of the pod.
  3. 03Assign the pod to a named worker in the Overguard app.
  4. 04The worker appears on the live site map.
Total: under 4 minutes per device.
INTELLIGENT FILTERING

False alerts erode trust. We engineer them out.

Vehicle detection

When GPS speed crosses 15 km/h, the IMU is reweighted and high-G events are tagged as vehicular. No fall alert when a worker takes the haul road.

Helmet removal detection

IMU plus on-device ML recognises when a helmet has been set down. The alert pipeline flags the worker as off-helmet rather than firing a man-down.

Graduated alert pipeline

Detection, confirmation, worker check-in, then alert. Every event passes through the same four gates before it reaches a supervisor.

Site learning. The platform learns site-specific patterns after two weeks. False positives approach near-zero by week four.

SPECIFICATIONS

The full breakdown.

Dimensions
85 × 55 × 28 mm
Weight
165 g
Helmet attachment
Clip system, EN 397 compatible
Application processor
ARM Cortex-A
Safety processor
ARM Cortex-M4 (always-on)
Operating system
FreeRTOS safety core
Local storage
72 hours rolling buffer
Operating range
−20°C to +60°C
Status indicators
3-LED strip + haptic
Inputs
SOS button, NFC tag, USB-C
Charging
Magnetic pogo-pin dock + USB-C

Bring the S1 to your next site.

Request pilot access→Book a walkthrough